Active compression device, method of assembly and method of use

文档序号：1159795 发布日期：2020-09-15 浏览：6次中文

阅读说明：本技术 主动压缩装置，组装方法和使用方法 (Active compression device, method of assembly and method of use ) 是由 A·彼得森 D·S·萨维奇 P·J·欣德里希斯 A·K·帕默 M·P·布伦策尔 W·F·奥于 2018-12-04 设计创作，主要内容包括：用于连接组织的压缩装置及其使用和制造方法。(Compression devices for joining tissue and methods of use and manufacture thereof.)

1. An apparatus for producing active compression of a bone segment, comprising:

a distal bone engaging portion;

a proximal bone engaging portion;

a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by perforating a sidewall of the device; and

a plurality of radial deformation-limiting features formed along a length of the helical strut, each radial deformation-limiting feature of the plurality of radial deformation-limiting features being formed by an asymmetrically-shaped receiving portion and a corresponding asymmetrically-shaped protruding portion defined by opposing sides of the helical strut;

the first linear side of the receiving portion and the corresponding first linear side of the protruding portion and the second linear side of the receiving portion and the corresponding second linear side of the protruding portion are opposite the first linear side of the receiving portion and the protruding portion, are inclined in the same direction with respect to a longitudinal center axis of the device and are not parallel to each other.

2. The device of claim 1, wherein the distal bone engaging portion comprises threads.

3. The device of claim 1, wherein an outer diameter of the proximal bone engaging portion is greater than an outer diameter of the helical strut.

4. The device of claim 1, wherein the perforations are formed through a sidewall of the device, perpendicular to a longitudinal central axis of the device and parallel to a radius of the longitudinal central axis.

5. The device of claim 1, wherein the perforations comprise a non-uniform width between a distal end and a proximal end of the perforations when the device is in a relaxed, undeformed state.

6. The device of claim 1, wherein the helical strut comprises a superelastic alloy.

7. The apparatus of claim 1, wherein each radial deformation limiting feature of the plurality of radial deformation limiting features has only three linear sides.

8. The apparatus of claim 1, wherein each radial deformation limiting feature of the plurality of radial deformation limiting features has 4 to 9 linear sides.

9. The apparatus of claim 1, wherein a first linear side of the receiving portion of a first radial deformation limiting feature of the plurality of radial deformation limiting features comprises a longitudinal length limiting protrusion that engages a respective longitudinal length limiting protrusion of a respective first linear side of a respective protruding portion of the first radial deformation limiting feature.

10. The device of claim 9, wherein a dimension between the longitudinal length limiting projection of the first linear side of the receiving portion and the longitudinal length limiting projection of the first linear side of the protruding portion is in a range of 0.010 to 0.100 inches.

11. The device of claim 1, wherein the distal bone engaging portion includes threads wound in a direction opposite to a direction in which the helical strut is wound.

12. A device for creating an actively compressed bone segment, comprising:

a distal bone engaging portion;

a proximal bone engaging portion;

a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by perforation of a side wall of the device; and

a plurality of radial deformation limiting features formed along a length of the helical strut, each radial deformation limiting feature of the plurality of radial deformation limiting features formed by an asymmetrically-shaped receiving portion and an asymmetrically-shaped protruding portion defined by opposing sides of the helical strut, the receiving portion having a shape that is different from a shape of the protruding portion.

13. The device of claim 12, wherein the distal bone engaging portion comprises threads.

14. The device of claim 12, wherein an outer diameter of the proximal bone engaging portion is greater than an outer diameter of the helical strut.

15. The device of claim 12, wherein the perforations are formed through a sidewall of the device, perpendicular to a longitudinal central axis of the device and parallel to a radius of the longitudinal central axis.

16. The apparatus of claim 12, wherein the helical strut comprises an alloy having a nickel content in excess of 50%.

17. The device of claim 12, wherein the first linear side of the receiving portion of a first radial deformation limiting feature of the plurality of radial deformation limiting features comprises a longitudinal length limiting protrusion that engages with a respective longitudinal length limiting protrusion of the respective first linear side of the respective protruding portion of the first radial deformation limiting feature.

18. The device of claim 17, wherein a dimension between the longitudinal length limiting projection of the first linear side of the receiving portion and the longitudinal length limiting projection of the first linear side of the protruding portion is in a range of 0.010 to 0.200 inches.

19. The apparatus of claim 17, wherein the second linear side of the receiving portion of a first radial deformation limiting feature of the plurality of radial deformation limiting features includes a longitudinal length limiting protrusion that engages a corresponding longitudinal length limiting protrusion of a corresponding second linear side of a corresponding protruding portion of a second radial deformation limiting feature.

20. An apparatus for producing active compression of a bone segment, comprising:

a distal bone engaging portion;

a proximal bone engaging portion;

a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by perforation of a side wall of the device, the helical structure allowing longitudinal deformation of the device in the range of 1 to 10 mm; and

the resulting tension between the distal bone engaging portion and the proximal bone engaging portion is in the range of 10 to 1000 newtons when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed, substantially relaxed state.

21. The device of claim 20, wherein the device is subjected to a torsional force in the range of 0.1 to 6 newton meters.

Technical Field

The present invention relates generally to general surgical and orthopaedic implants and more particularly, but not exclusively, to implanting devices for assisting bone fusion and repair. The present invention relates to a compression device for connecting two bone fragments, and to an associated device for implanting such a device, to a method for compressing and/or fixing bone fragments over a prolonged period of time, and to the manufacture of such a device.

Background

Fractures and other bone diseases are commonly treated by fusion. Currently, bone is fused together with the aid of implants, such as pins, rods, plates, and screws, which are designed to hold the bone or bone fragments in place as healing occurs and the bone or bone pieces are fused together. The compression may serve to join or stabilize two bone fragments and to aid in the healing of the bone fragments. Examples of compression bone screws are known in the art, each having a different degree of efficacy.

The goal of arthrodesis is to create a stable bond between the intended fusion surfaces. Although the pressure from standard screw placement is dynamic during application, once the screw is tightened, it acts as a static device and cannot hold the compressive load while the bone remodels. Maintaining a compressive load across the fusion surface and reducing stress shielding can aid healing. The stability of screw compression may also be affected by several factors, such as bone density, bone resorption and fixation direction. It may be desirable to have a device that delivers effective or prolonged dynamic compression at the desired fusion site to promote healing. Bottlang, Michael PhD; tsai, Stanley MS; bliven, Emily K.BS; von Rechenberg, Brigitte DVM; kindt, Philipp DVM; augat, Peter PhD; henschel, Julia BS; fitzpatrick, Daniel c.md; md, details of these benefits are further described in Journal of orthopaedic Trauma, volume 31, phase 2, pages 71-77, 2017, the entire contents of which are incorporated herein by reference.

There is the concept of an active compression screw. The term "active" is defined as having some ability to stretch axially over the length of the member. However, these concepts have complicated surgical procedures. Current active compression screw concepts are limited in their ability to change length according to the ratio of the screw lengths, and limited in the amount of axial force according to the ratio of the screw lengths. Current active compression screws do not have the ability to adjust compression or do not have adjustable compression over time. Current active compression screw concepts do not have a simple construction, making manufacture complex and expensive, and finally, current platforms cannot be scaled down to the treatment diameter for ossicles. Accordingly, there is a need for improved devices and methods for fusing bones together.

Disclosure of Invention

The present invention is directed to methods and devices for matter herein that surround a novel compression device, system and method for compressing suitable materials. In certain embodiments, the present invention relates to devices and methods for providing active compression to bone segments having a single continuous structural configuration. The phrase "single continuous structure" is defined as a structure formed from one material and only the material is removed to create the final construction, and no separate components or elements need be connected to create the final construction.

The phrase "active compression" is defined as continuous axial tension over a given change in length of a member, such as an axial spring. The ability to vary the length may be in the range of 1% -20% of the length of the member. In contrast, a standard screw cannot provide axial tension or compression when the change in length exceeds a configured elastic limit, which is typically a small deformation of 1%, defined herein as "passive compression".

In certain embodiments of the present invention, a device for providing active compression of a bone segment comprised of two or more members is provided. In certain embodiments, these devices have screw-like features. The deployment or surgical method for inserting the device of the present invention is similar to the method of driving a screw-like body into a bone segment, similar to a conventional non-active compression screw. Because the entire inventive device may vary in length, in some embodiments the device may provide an effective therapeutic range or distance of active compressive force exceeding 6mm to include different levels of bone resorption. The amount of force required to promote bonding will vary depending on the anatomical feature being fused. The method and apparatus of the present invention may be scaled to accommodate a range of compressive axial forces of 0-200N, and possibly larger, depending on the diameter of the apparatus.

It is known that the desired force is applied for a period of time until the bones fuse. In certain embodiments of the present invention, an apparatus and method are provided wherein the apparatus provides active compression to a bone segment for a time period exceeding that of current compression screws until the time of bone healing or fusion. Over time, the amount of force required to promote bone healing may vary. However, the present invention allows for adjustment of the structural variables such that the device of the present invention transmits axial compressive forces in different amounts over time and length of extension. In addition, such structural variables may be adjusted to deliver consistent force over a given distance or time. The device of the present invention has the ability to be scaled down to an effective diameter for use with the ossicles of the hand and foot, which may be less than 2mm in diameter.

Activation of axial tension according to the present invention may be before, during, or after deployment of the device to the desired anatomy, allowing different surgical procedures to be developed and optimized for clinical benefit. To facilitate a common surgical approach that first deploys a guide pin or K-wire and then performs delivery of the device over the component, the device of the present invention may be cannulated. Alternatively, the device of the present invention may be non-hollow or solid. The present invention may incorporate all other known prior features that promote tissue interaction and compression generation.

The axial tension of the present invention is generated in several ways. One way that may be employed is by utilizing piercing or cutting features in and along the body of the device. These characteristics may be varied to provide the best criteria for axial tension, torsional stiffness, and bending stiffness for a given application. The force can be loaded into the axial tension member of the present invention in several ways. One of these is to create axial tension in the screw-like body threads that loads the members to provide initial compression and stabilization as the body is inserted into the bone segment. Alternatively, a delivery mechanism may be employed to load the axial force into the device. The force may also be preloaded by a retention mechanism on the exterior, interior, or entire device, such as by using an absorbable material. As noted above, there are many ways of generating, maintaining, and releasing axial pressure, thereby facilitating the performance of many procedural variations for delivering the therapeutic energy of the present invention.

In the present invention, devices and methods are provided in which a device constructed of a shape memory alloy SMA, such as Nitinol, provides customized axial, torsional, bending, radial, shear and/or compressive forces to a bone segment. The present invention relates to a device, system and method that initially compresses and/or tensions a suitable material, particularly bone fragments, at the time of implantation and for a period of time after implantation.

The present invention further relates to engagement members, such as movable bone screws and methods of use thereof, for securing portions of tissue and/or bone while providing a particular amount of desired flexion or elasticity to promote stronger healing of a fracture or fusion, such as to increase the torsional strength of the fracture or fusion after healing. The present invention also relates to an engagement member, such as a movable rod and/or plate, and methods of use thereof, for immobilizing a portion of tissue and/or bone while providing a certain amount of desired flexion or elasticity to promote stronger healing of a fracture or fusion, such as to increase the torsional strength of the fracture or fusion after healing.

The described invention may be used with or without orthopedic wound plates and/or intramedullary nails and/or pins, rods and/or external fixation devices. The described invention may be used with solid screws, cannulated screws, headed and/or headless screws, rods, nails, plates, nails, suture anchors, and soft tissue anchors. Threads are generally depicted in this disclosure as tissue anchoring mechanisms. However, it is within the scope of the present invention to include all alternative anchoring mechanisms on one or more ends of the device providing the anchoring, including, but not limited to, expansion mechanisms, cross-linking members, cements, adhesives, sutures, and other components commonly found in orthopedic surgery.

The present invention further relates to engagement members, such as bone screws and methods of use thereof, for securing a bone shaft and/or plate to a portion of tissue and/or bone while providing a certain amount of desired flexion or elasticity to promote stronger healing of a fracture or fusion, such as to increase the torsional strength of the healed fracture or fusion. In certain embodiments, such rods and/or plates are inactive rods and/or plates, and the active engagement members of the present invention provide active force or deflection to the system. In certain embodiments, such rods and/or plates are active rods and/or plates, and the active rods and/or plates and active connecting members of the present invention both provide active force or deflection to the system.

Certain embodiments of the present invention provide an apparatus for generating active compression, the apparatus comprising: a distal bone engaging portion; and a proximal bone engaging portion having an outer diameter greater than an outer diameter of the distal bone engaging portion; a central portion is interposed between the proximal and distal bone engaging portions, the central portion having a perforation formed therethrough that facilitates changing the size of the device. Wherein the device has an integral continuous structure. Wherein the device is hollow. Wherein the proximal bone engaging portion includes threads having a pitch different from a pitch of the distal bone engaging portion. Wherein the distal bone engaging portion includes threads. Wherein the perforations comprise a non-uniform shape. Wherein the perforations comprise a spiral form. Wherein the change in device size comprises a change in length. Wherein the change in device size comprises a shortening of the device length. Wherein the change in device size comprises a change in device size over a period of greater than 12 hours.

Certain embodiments of the present invention provide an apparatus for generating active compression, the apparatus comprising: a hollow body having a compressive preload feature; a plurality of perforations formed through a sidewall of the perforated body; and a dimension that changes when the plurality of perforations are deformed by activating the compressive preload feature. Wherein the exterior of the sidewall of the hollow body comprises threads. Wherein the dimension comprises the length of the device. Wherein the compressive preload feature comprises a plurality of threads having different pitches formed on the exterior of the sidewall of the hollow body. Wherein the activation comprises a rotation of the device.

Certain embodiments of the present invention provide a method of actively compressing a bone segment, the method comprising: applying a longitudinal tensile stress to the hollow body by deformation of perforations formed through a sidewall of the hollow body; inserting a cannula body into the first bone segment and the second bone segment; and releasing the tensile stress over a period of time; the first and second bone segments are compressed by releasing the tensile stress. Wherein a longitudinal tensile stress is applied to the cannula body by deforming the perforations formed through the side wall of the cannula body, and the cannula body is inserted simultaneously into the first bone segment and the second bone segment. Wherein applying a longitudinal tensile stress to the hollow body through deformation of perforations formed through a sidewall of the hollow body comprises rotating a plurality of threads having different pitches formed on an exterior of the sidewall of the hollow body. Wherein applying a longitudinal tensile stress to the hollow body through deformation of perforations formed through a sidewall of the hollow body comprises elongating the hollow body.

Certain embodiments of the present invention provide an apparatus for generating active compression, the apparatus comprising: a proximal anchoring portion; a distal anchoring portion; a plurality of struts formed of a superelastic material are inserted between the proximal and distal anchor portions. A first state having an axial elastic potential energy generated by deformation of at least one strut of the plurality of struts; a second state in which the axial elastic potential energy is released non-linearly with respect to the displacement of the proximal anchoring portion with respect to the distal anchoring portion. Wherein the axial elastic potential energy comprises axial tensile elastic potential energy. Wherein the axial elastic potential energy comprises axial compression elastic potential energy. Wherein the transition from the first state to the second state comprises a transition of at least one strut of the plurality of struts from a high energy state to a low energy state. Wherein the transition from the first state to the second state comprises a transition of at least one strut of the plurality of struts from a deformed state to an undeformed state.

Certain embodiments of the present invention provide an apparatus for creating actively compressed bone segments, the apparatus comprising: a distal bone engaging portion; a proximal bone engaging portion; a central portion that facilitates changing a size of a device inserted between the proximal and distal bone engaging portions, the central portion having a perforation formed through a sidewall of the central portion; and a limiting feature formed by opposing sides of the perforation that limits the variation in the size of the device facilitated by the perforation. Wherein the device has a single continuous structure; the device is hollow; the proximal bone engaging portion includes threads having a pitch different from the pitch of the distal bone engaging portion. The distal bone engaging portion includes threads; the limiting feature limits the variation in length of the device; the limiting feature limits the variation of the circumference of the device; the perforations comprise a helical form defining a continuous helical strut. The confinement feature has a stepped shape; the perforations are formed by radii of the sidewalls perpendicular to the longitudinal central axis of the device and parallel to the longitudinal central axis; and/or the change in device size comprises a change in device size over a period of greater than 12 hours.

Certain embodiments of the present invention provide an apparatus for producing active compression of a bone segment, the apparatus comprising: a hollow body having a compressive preload feature; perforations formed through the sidewall of the hollow body; and a dimension that changes when the perforation deforms by activating the compressive preload feature, the changed dimension being limited by corresponding change limiting features formed on opposite sides of the perforation. Wherein the exterior of the sidewall of the hollow body comprises threads; the dimension that changes when the perforation is deformed includes the length of the device. The compressive preload feature comprises a plurality of threads having different pitches formed on the exterior of the sidewall of the hollow body. And/or activation of the compressive preload feature comprises rotation of the device.

Certain embodiments of the present invention provide a method of actively compressing a bone segment, comprising: inserting cannulated screws into the first and second bone segments; applying a longitudinal tensile stress to the cannula body by deformation of a perforation formed through a sidewall of the cannula body; limiting deformation of the perforations by engaging corresponding deformation limiting features formed in opposing sidewalls of the perforations; releasing the tensile stress over a period of time; the first and second bone segments are compressed by releasing the tensile stress. While cannulated screws are inserted into the first and second bone segments and longitudinal tensile stress is applied to the hollow body by deformation of perforations formed through the sidewall of the hollow body. The cannulated screws are simultaneously inserted into the first and second bone segments and longitudinal tensile stress is applied to the hollow body by deformation of perforations formed through the sidewall of the hollow body. Applying a longitudinal tensile stress to the hollow body through deformation of perforations formed through a sidewall of the hollow body comprises: rotating a plurality of threads having different pitches formed on an exterior of a sidewall of a hollow body; restricting and/or limiting deformation of the perforations by engaging corresponding deformation limiting features formed in opposing sidewalls of the perforations includes limiting an increase in length or an increase in circumference of the hollow body.

Certain embodiments of the present invention provide an apparatus for creating active compression between bone segments, the apparatus comprising: a proximal anchoring portion; a distal anchoring portion; a spring formed of a superelastic material is interposed between the proximal anchor portion and the distal anchor portion. A first state having an axial elastic potential energy generated by deformation of the spring; a second state in which the axial elastic potential energy is released non-linearly with respect to the displacement of the proximal anchoring portion with respect to the distal anchoring portion. Wherein the spring includes corresponding deformation limiting features formed on opposite sides of the spring; the axial elastic potential energy comprises axial compression elastic potential energy. The transition from the first state to the second state comprises a transition of the spring from a high energy state to a low energy state; the transition from the first state to the second state comprises a transition of the spring from a deformed state to a non-deformed state; the spring is positioned on the longitudinal axis of the device, adjacent the proximal anchoring portion; the spring is helical; and/or the spring is a beveled washer.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; and a deformation limiting feature is formed on the helical strut to limit deformation of the helical strut about the longitudinal axis of the device when a torsional force is applied to the device such that both the distal and proximal ends of the device rotate at substantially the same frequency. Wherein the torsional force comprises a torsional force in a first direction or a second opposite direction; and/or deformation of the helical strut about the longitudinal axis of the device comprises radial deformation and/or longitudinal deformation.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a spring element disposed between the distal end and the proximal end. And a deformation limiting feature formed on the spring element, the deformation limiting feature limiting deformation of the device to longitudinal deformation of the device along a longitudinal axis of the device when a torsional force is applied to the device. Wherein the torsional force comprises a torsional force in a first direction or a second opposite direction; and/or deformation of the device along a longitudinal axis of the device includes an increase in the length of the device.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; the deformation limiting feature formed on the helical strut has a non-linearly increasing load curve when a linearly increasing torsional force is applied to the device.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; the deformation limiting feature formed on the helical support has a non-linearly increasing load curve when a linearly increasing axial force is applied to the device. Wherein the torsional force comprises a torsional force in a first direction or a second opposite direction.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; and a deformation-limiting feature formed on the helical strut, the deformation-limiting feature limiting deformation of adjacent portions of the helical strut relative to one another when a torsional force is applied to the device. Wherein the torsional force comprises a torsional force in a first direction or a second opposite direction; and/or the deformation of adjacent portions of the helical strut relative to each other includes radial deformation and/or longitudinal deformation.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; and a deformation limiting feature formed on the screw rod, the deformation limiting feature allowing a predetermined deformation of the screw rod when a torsional force is applied to the device and then limiting a continuous deformation of the screw rod. Wherein the torsional force comprises a torsional force in a first direction or a second opposite direction; the predetermined deformation comprises a longitudinal deformation and/or a radial deformation; and/or the predetermined deformation of the screw rod comprises a displacement of the screw rod in the range of 1 mm to 10 mm.

Certain embodiments of the present invention provide an apparatus, comprising: a distal end; a proximal end; a helical strut disposed between the distal end and the proximal end; and a deformation-limiting feature formed on the helical rod, the deformation-limiting feature limiting deformation of the helical rod in a first direction when a torsional force is applied to the device and allowing deformation of the helical rod in a second direction. Wherein the deformation of the screw rod in the first direction comprises a longitudinal deformation and the deformation of the screw rod in the second direction comprises a radial deformation; the deformation of the helical strut in the first direction comprises a radial deformation, and the deformation of the helical strut in the second direction comprises a longitudinal deformation; and/or the torsional force comprises a torsional force in a first direction or a second opposite direction.

Certain embodiments of the present invention provide an apparatus for creating actively compressed bone segments, the apparatus comprising: a distal bone engaging portion; a proximal bone engaging portion; a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by perforation of the device sidewall. A plurality of radial deformation-limiting features formed along a length of the helical strut, each radial deformation-limiting feature of the plurality of radial deformation-limiting features being formed by an asymmetrically-shaped receiving portion and a corresponding asymmetrically-shaped protruding portion defined by opposing sides of the helical strut; the first linear side of the receiving portion and the corresponding first linear side of the protruding portion and the second linear side of the receiving portion and the corresponding second linear side of the protruding portion are inclined in the same direction with respect to the longitudinal center axis of the device and are not parallel to each other, opposite to the first linear sides of the receiving portion and the protruding portion. Wherein the distal bone engagement portion comprises threads; the proximal bone engaging portion has an outer diameter greater than an outer diameter of the helical strut. Perforations are formed through the sidewall of the device at a radius perpendicular to the longitudinal central axis of the device and parallel to the longitudinal central axis. The perforation has a non-uniform width between the distal and proximal ends of the perforation when the device is in a relaxed, undeformed state; the helical strut comprises a superelastic alloy. Each radial deformation limiting feature of the plurality of radial deformation limiting features has only three linear sides. Each radial deformation limiting feature of the plurality of radial deformation limiting features has 4 to 9 linear sides. Each radial and axial deformation limiting feature of the plurality of radial deformation limiting features has 4, 5, 6, 7, 8, or 9 linear sides. Each radial and length deformation limiting feature of the plurality of radial deformation limiting features is in a radial aspect of the feature and not in an axial aspect; the first linear side of the receiving portion of a first radial deformation limiting feature of the plurality of radial deformation limiting features comprises: a longitudinal length limiting protrusion engaging a respective longitudinal length limiting protrusion of a respective first linear side of a respective projecting portion of the first radial deformation limiting feature; a dimension between the longitudinal length limiting projection of the first linear side of the receiving portion and the longitudinal length limiting projection of the first linear side of the protruding portion is in a range of 0.010 to 0.100 inches; and/or the device is hollow; the distal bone engaging portion includes threads wound in a direction opposite to the direction in which the helical strut is wound.

Certain embodiments of the present invention provide an apparatus for creating actively compressed bone segments, the apparatus comprising: a distal bone engaging portion; a proximal bone engaging portion; a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by a perforation through the sidewall of the device. A plurality of radial deformation limiting features formed along a length of the helical strut, each radial deformation limiting feature of the plurality of radial deformation limiting features being formed by an asymmetrically-shaped receiving portion and an asymmetrically-shaped projecting portion, the asymmetrically-shaped projecting portion being defined by opposing sides of the helical strut, the receiving portion being shaped differently than the projecting portion. Wherein each of these shapes facilitates translation relative to each other over a defined length and, once that length is achieved, resists or limits further movement or translation relative to each other by contacting and engaging opposing features; the distal bone engaging portion includes threads; the proximal bone engaging portion has an outer diameter greater than an outer diameter of the helical strut. Perforations are formed through the sidewall of the device at a radius perpendicular to the longitudinal central axis of the device and parallel to the longitudinal central axis. The perforations comprise a non-uniform width between the distal and proximal ends of the perforations with the device in a relaxed, undeformed state; the helical strut comprises an alloy having a nickel content in excess of 50%; the helical strut comprises a superelastic alloy. The helical strut comprises nitinol; the helical struts comprise an alloy of more than 50% nickel; the first linear side of the receiving portion of a first radial deformation limiting feature of the plurality of radial deformation limiting features comprises: a longitudinal length limiting protrusion engaging a respective longitudinal length limiting protrusion of a respective first linear side of a respective projecting portion of the first radial deformation limiting feature; a dimension between the longitudinal length limiting projection of the first linear side of the receiving portion and the longitudinal length limiting projection of the first linear side of the protruding portion is in a range of 0.010 to 0.200 inches; and/or the second linear side of the receiving portion of the first of the plurality of radial deformation limiting features comprises: a longitudinal length limiting rib engaged with a respective longitudinal length limiting rib of a respective second linear side of a respective projecting portion of the second radial deformation limiting feature.

Certain embodiments of the present invention provide an apparatus for producing active compression of a bone segment, the apparatus comprising: a distal bone engaging portion; a proximal bone engaging portion; a helical strut interposed between the proximal and distal bone engaging portions, the helical strut being formed by perforation of the device side wall, the helical structure allowing longitudinal deformation of the device in the range of 1 to 10 mm; the resulting tension between the distal and proximal bone engaging portions is in the range of 10 to 1000 newtons when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed, substantially relaxed state. The device further comprises a torsional force in the range of 0.1 to 6 newton meters generated between the distal bone engaging portion and the proximal bone engaging portion when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed substantially relaxed state and/or when the device is inserted into bone tissue. Wherein the device is subjected to a torsional force in the range of 0.1 to 6 newton meters.

Drawings

These and other aspects, features and advantages which embodiments of the present invention are capable of will become apparent and elucidated from the following description of embodiments of the invention, with reference to the accompanying drawings:

FIG. 1 is a side view of a bone fixation device inserted into two non-reducing bone segments in a non-expanded state according to an aspect of the present invention;

FIG. 2 is a side view of a bone fixation device inserted into two reduced bone segments in an expanded, tensioned state according to an aspect of the present invention;

FIG. 3 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state according to an aspect of the present invention;

FIG. 4 is a graph depicting the compressive force exerted over time by a device according to the present invention relative to a standard screw;

FIG. 5 is a side view of a bone fixation device inserted into two unreduced bone segments in an expanded state according to an aspect of the present invention;

FIG. 6 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state according to an aspect of the present invention;

FIG. 7 is an illustration of an exemplary bone in human anatomy in accordance with an aspect of the present invention in which the disclosed invention may be utilized;

FIG. 8 is an illustration of exemplary bones in the human hand anatomy in which the disclosed invention may be utilized in accordance with an aspect of the present invention;

FIG. 9 is an illustration of an exemplary bone in the human foot anatomy in accordance with an aspect of the present invention in which the disclosed invention may be utilized;

FIG. 10 is an illustration of an exemplary bone in the human foot anatomy in accordance with an aspect of the present invention in which the disclosed invention may be utilized;

FIG. 11 is an illustration of an exemplary bone in human anatomy in accordance with an aspect of the present invention in which the disclosed invention may be utilized;

fig. 12 is a side view of a bone fixation device in an expanded state according to an aspect of the present invention;

FIG. 13 is a side view of a bone fixation device in a non-expanded state according to an aspect of the present invention;

FIG. 14 is an enlarged side view of a portion of a deformable or expandable section of a bone fixation device in an expanded state according to an aspect of the present invention;

FIG. 15 is an enlarged side view of a portion of a deformable or expandable section of a bone fixation device in a non-expanded state according to an aspect of the present invention;

fig. 16 is a plan view of a bone fixation device according to an aspect of the present invention;

FIG. 17 is a side cross-sectional view of a bone fixation device in a non-expanded state according to an aspect of the present invention;

FIG. 18 is a side view of a bone fixation device in a non-expanded state according to an aspect of the present invention;

FIG. 19 is a perspective view of a bone fixation device in a non-expanded state according to an aspect of the present invention;

fig. 20 is a perspective view of a bone fixation device in an expanded state according to an aspect of the present invention;

FIG. 21 is a side view of a bone fixation device having an unthreaded expandable section in a non-expanded state according to an aspect of the present invention;

FIG. 22 is a side view of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 23 is a side view of a bone fixation device having an unthreaded expandable section in a non-expanded state according to an aspect of the present invention;

FIG. 24 is a side view of a bone fixation device having an expandable section without threads in an expanded state according to an aspect of the present invention;

FIG. 25 is a side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member in accordance with an aspect of the present invention;

FIG. 26 is a side view of a threaded central member according to an aspect of the present invention;

FIG. 27 is an enlarged side cross-sectional view of a bone fixation device having a threaded distal section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 28 is a side cross-sectional view of a bone fixation device having a threaded distal section in a non-expanded state according to an aspect of the present invention;

FIG. 29 is a perspective view of a bone fixation assembly having a threaded expandable section in an unexpanded state and internal distal threads having a threaded central member and a proximal head retaining collet mechanism in accordance with an aspect of the present invention;

FIG. 30 is a side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member and a proximal head retention collet mechanism (proximai head retention collet mechanism) in accordance with an aspect of the present invention;

FIG. 31 is a side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member and a proximal head retaining collet mechanism in accordance with an aspect of the present invention;

FIG. 32 is a perspective view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member and a proximal head retaining driver mechanism in accordance with an aspect of the present invention;

FIG. 33 is a side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member and a proximal head retaining driver mechanism in accordance with an aspect of the present invention;

FIG. 34 is an enlarged, cross-sectional, side view of a portion of a bone fixation assembly having a threaded expandable section in a non-expanded state and internal distal threads having a threaded central member and a proximal head retaining driver mechanism in accordance with an aspect of the present invention;

FIG. 35 is a side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and a distal internal thread having a threaded central member and a proximal head retaining driver mechanism and a proximal head retaining collet mechanism in accordance with an aspect of the present invention;

FIG. 36 is an enlarged, side cross-sectional view of a bone fixation assembly having a threaded expandable section in a non-expanded state and distal internal threads having a threaded central member, a proximal head retaining driver mechanism and a proximal head retaining collet mechanism in accordance with an aspect of the present invention;

FIG. 37 is a perspective view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 38 is a perspective view of a portion of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 39 is a perspective view of a portion of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 40 is a perspective view of a bone fixation assembly having a non-threaded expandable section with a central member having a distal retention feature and a proximal retention feature in an unexpanded state according to an aspect of the present invention;

FIG. 41 is a perspective view of a central member having distal and proximal retention features in accordance with an aspect of the present invention;

FIG. 42 is a side view of a bone fixation device having a non-threaded expandable section with distal and proximal retention features in a non-expanded state according to an aspect of the present invention;

FIG. 43 is a side view of a bone fixation device having a non-threaded expandable section with a central outer reinforcing member in a non-expanded state according to an aspect of the present invention;

FIG. 44 is a side cross-sectional view of a bone fixation device having a non-threaded expandable section with a central outer reinforcing member in a non-expanded state according to an aspect of the present invention;

FIG. 45 is a side view of a bone fixation device having an unthreaded expandable section with a central dissolvable member in an expanded state according to an aspect of the present invention;

FIG. 46 is a side cross-sectional view of a bone fixation device having an unthreaded expandable section with a central dissolvable member in an expanded state, according to an aspect of the present invention;

FIG. 47 is a side view of a threaded central member having a proximal head retaining mechanism in accordance with an aspect of the present invention;

FIG. 48 is a side cross-sectional view of a bone fixation assembly having a non-threaded expandable section in a non-expanded state and proximal internal threads having a threaded central member with a proximal head retaining mechanism in accordance with an aspect of the present invention;

FIG. 49 is an enlarged side cross-sectional view of a bone fixation assembly having an unthreaded expandable section in an expanded state and proximal internal threads of a threaded central cannula member having a central proximal head retaining mechanism in accordance with an aspect of the present invention;

FIG. 50 is a side cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state with a central internal reinforcing member according to an aspect of the present invention;

fig. 51 is a side view of a bone fixation multi-component device having an unthreaded expandable section with a central internal reinforcing member without a captured, but possibly freely rotatable, proximal headpiece in a non-expanded state according to an aspect of the present invention;

fig. 52 is a side cross-sectional view of a bone fixation multi-component device having an unthreaded expandable section with a central internal reinforcing member without a captured, but possibly freely rotatable, proximal head member in a non-expanded state, according to an aspect of the present invention;

FIG. 53 is a side view of a bone fixation multi-component device having an unthreaded expandable section with a central internal reinforcing member and a captured, but possibly freely rotatable, proximal headpiece in a non-expanded state according to an aspect of the present invention;

FIG. 54 is a side cross-sectional view of a bone fixation multi-component device having an unthreaded expandable section with a central internal reinforcing member and a captured, but possibly freely rotatable, proximal headpiece in a non-expanded state according to an aspect of the present invention;

FIG. 55 is a perspective view of a central internal stiffening member having threaded distal engagement features and a proximal head member according to an aspect of the present invention;

fig. 56 is a side view of a bone fixation multi-component device having an unthreaded expandable segment with a threaded distal engagement feature in an expanded state according to an aspect of the present invention;

FIG. 57 is a side cross-sectional view of a bone fixation multi-component device having an unthreaded expandable section in an expanded state having a central internal reinforcing member with a threaded distal engagement feature and a proximal head member in accordance with an aspect of the present invention;

FIG. 58 is a side cross-sectional view of a bone fixation multi-component device having an unthreaded expandable section in a non-expanded state having a central internal reinforcing member with a threaded distal engagement feature and a proximal head member in accordance with an aspect of the present invention;

FIG. 59 is a side view of a bone fixation multipart device having an unthreaded expandable section with a central internal reinforcing member having a threaded distal engagement feature and a proximal head member in a non-expanded state according to an aspect of the present invention;

FIG. 60 is a side view of a bone fixation device having a proximal head engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 61 is an enlarged side cross-sectional view of a bone fixation device having a proximal head engagement feature in a non-expanded state in accordance with an aspect of the present invention;

fig. 62 is a perspective view of a bone fixation device in a non-expanded state having a freely rotating proximal head engaging feature in accordance with an aspect of the present invention;

FIG. 63 is an enlarged cross-sectional side view of a bone fixation device having a freely rotating proximal head engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 64 is a side view of a bone fixation device having a tapered smaller diameter and variable pitch thread feature in a non-expanded state according to an aspect of the present invention;

FIG. 65 is a side cross-sectional view of a bone fixation device having a tapered smaller diameter and variable pitch thread feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 66 is a side view of a bone fixation device having variable minor and major diameters and a three lead pitch thread feature in a non-expanded state according to an aspect of the present invention;

FIG. 67 is a side cross-sectional view of a bone fixation device having variable minor and major diameters and a three lead pitch thread feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 68 is a perspective view of a bone fixation device having variable minor and major diameters and a three lead pitch thread feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 69 is a perspective view of a bone fixation device in a non-threaded, non-expanded state having variable minor and major diameters and distal triple lead pitch and proximal thread features in accordance with an aspect of the present invention;

FIG. 70 is a side cross-sectional view of a bone fixation device having variable minor and major diameters and a triple pitch thread feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 71 is a side cross-sectional view of a bone fixation device in an unthreaded, non-expanded state having variable minor and major diameters and distal triple lead pitch and proximal thread features in accordance with an aspect of the present invention;

FIG. 72 is a perspective view of a bone fixation device having a helically shaped expandable section without threads in an unexpanded state in accordance with an aspect of the present invention;

FIG. 73 is a perspective view of a bone fixation assembly having an unthreaded, helically expandable section with a helical expansion member and a driver in a non-expanded state in accordance with an aspect of the present invention;

FIG. 74 is a perspective view of a bone fixation assembly having an unthreaded, helically expandable section with a helical expansion member and a driver and central member in a non-expanded state in accordance with an aspect of the present invention;

FIG. 75 is a perspective view of a bone fixation assembly having a non-threaded helically expandable section with a helical expansion member and driver and central member in an expanded state in accordance with an aspect of the present invention;

FIG. 76 is a perspective view of a bone fixation assembly having an unthreaded, helically expandable section with a helically expandable member and a driver and central member in an expanded state in accordance with an aspect of the invention;

FIG. 77 is a perspective view of a bone fixation assembly having an unthreaded, helically expandable section with a helical expansion member and a driver in an expanded state in accordance with an aspect of the present invention;

FIG. 78 is a perspective view of a bone fixation assembly having a non-threaded helically expandable section with a helical expansion member and driver in a non-expanded state in accordance with an aspect of the present invention;

FIG. 79 is a side cross-sectional view of a bone fixation assembly having an unthreaded, helically expandable section with a helical expansion member and a driver and central member in an expanded state in accordance with an aspect of the present invention;

FIG. 80 is a perspective view of a bone fixation assembly having an unthreaded expandable section in a non-expanded state and having a trans-axial engagement member in the bone in accordance with an aspect of the present invention;

FIG. 81 is a perspective view of a bone fixation assembly having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 82 is a perspective view of a bone fixation assembly having an unthreaded expandable section in an expanded state in accordance with an aspect of the present invention;

FIG. 83 is a side cross-sectional view of a bone fixation assembly having a non-threaded expandable section with a central member in a non-expanded state in accordance with an aspect of the present invention;

FIG. 84 is a side view of a bone fixation assembly having a non-threaded expandable section with a central member in a non-expanded state in accordance with an aspect of the present invention;

FIG. 85 is a side cross-sectional view of a bone fixation assembly having a non-threaded expandable section with a central member and a retaining feature in an expanded state in accordance with an aspect of the present invention;

FIG. 86 is an end view of a bone fixation assembly having an unthreaded expandable section with a central member and a retaining feature in an expanded state according to an aspect of the present invention;

FIG. 87 is a side cross-sectional view of a bone fixation assembly having a non-threaded expandable section with a central member and a retaining feature in an expanded state in accordance with an aspect of the present invention;

FIG. 88 is a side view of a portion of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 89 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 90 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state, according to an aspect of the present invention;

FIG. 91 is a side view of a portion of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 92 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 93 is a partial side view of a portion of a cut groove pattern of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 94 is a partial side view of a portion of a cut groove pattern of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 95 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state, according to an aspect of the present invention;

FIG. 96 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 97 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 98 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 99 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 100 is a side view of a bone fixation device having a non-threaded helically expandable section in a non-expanded state according to an aspect of the present invention;

FIG. 101 is a side cross-sectional view of a bone fixation device having a non-threaded helically expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 102 is a side view of a bone fixation device having a non-threaded section in accordance with an aspect of the present invention;

FIG. 103 is a graph illustrating a material strain curve in accordance with an aspect of the present invention;

FIG. 104 is an enlarged perspective view of a bone fixation device having a three-pronged, expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 105 is a side view and an enlarged end view of a bone fixation device having a single lead thread segment in accordance with an aspect of the present invention;

FIG. 106 is a side view and an enlarged end view of a bone fixation device having a dual thread guide segment in accordance with an aspect of the present invention;

FIG. 107 is a side view and an enlarged end view of a bone fixation device having a triple lead thread segment in accordance with an aspect of the present invention;

FIG. 108 is an enlarged plan view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state, which section will be wrapped around the circumference of a body, resulting in two different modes, according to an aspect of the present invention;

FIG. 109 is an enlarged elevational view of a coupling feature of a bone fixation device having an expandable section without threads and a threaded section in an engaged state in accordance with an aspect of the present invention;

FIG. 110 is a side view of a bone fixation device having an unthreaded expandable section in a non-expanded state, the section having a diameter larger than the minor diameter of the threaded portion, according to an aspect of the present invention;

FIG. 111 is a side cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state, the section having a diameter larger than the minor diameter of the threaded portion, according to an aspect of the present invention;

FIG. 112 is a side view of a bone fixation device having a non-expandable non-threaded section in a non-expanded state, the section curved away from an axis of the threaded section, according to an aspect of the present invention;

FIG. 113 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 114 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 115 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 116 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 117 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 118 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 119 is a flow chart illustrating one embodiment of a method of manufacturing a bone fixation device according to the present invention;

FIG. 120 is a flow chart illustrating one embodiment of a method of manufacturing a bone fixation device in accordance with the present invention;

FIG. 121 is a flow chart illustrating one embodiment of a method of manufacturing a bone fixation device according to the present invention;

FIG. 122 is a flow chart illustrating one embodiment of a method of manufacturing a bone fixation device in accordance with the present invention;

FIG. 123 is a partial side view of a bone fixation device having an unthreaded expandable section with multiple expansion characteristics in a non-expanded state according to an aspect of the present invention;

FIG. 124 is a partial side view of a bone fixation device having an unthreaded expandable section having a plurality of expansion characteristics in an unexpanded state and having a deformation control feature in accordance with an aspect of the present invention;

FIG. 125 is a side view of a bone fixation device having an unthreaded expandable section having a plurality of expansion characteristics in an unexpanded state in accordance with an aspect of the present invention;

FIG. 126 is a side view of a bone fixation device having an unthreaded expandable section having radial expansion characteristics in an unexpanded state in accordance with an aspect of the present invention;

FIG. 127 is a side view of a bone fixation device having an unthreaded expandable section with radial expansion properties in a partially expanded state according to an aspect of the present invention;

FIG. 128 is a side view of a bone fixation device having an unthreaded expandable section with radial expansion properties in a fully expanded state in accordance with an aspect of the present invention;

FIG. 129 is a side cross-sectional view of a bone fixation device having a threaded distal section in a non-expanded state and a non-threaded expandable section, the expandable section having a diameter greater than the minor diameter of the threaded section, the distal section having features on an inner diameter that can engage and transmit torque and axial loads in accordance with an aspect of the present invention;

FIG. 130 is a side cross-sectional view of a bone fixation device assembly having a threaded distal section and a non-threaded expandable section in a non-expanded state, the expandable section having a diameter greater than the minor diameter of the threaded distal section, the distal section having features on an inner diameter that are engageable and capable of transmitting torque and axial loads, and having a drive mechanism engageable with the distal and proximal features of the device, in accordance with an aspect of the present invention;

FIG. 131 is a perspective view of a device assembly having a drive mechanism that engages a distal feature and a proximal end of the device in accordance with an aspect of the present invention; and

FIG. 132 is a perspective cross-sectional view of a bone fixation device assembly having a threaded distal section and a non-threaded expandable section in a non-expanded state, the expandable section having a diameter greater than the minor diameter of the threaded distal portion, the distal section having a feature on an inner diameter that can engage and transmit torque and axial loads, and a drive mechanism that can engage the distal feature and a proximal end of the device, in accordance with an aspect of the present invention;

Fig. 133 is a side view of a bone fixation device inserted into two unreduced bone segments according to an aspect of the present invention;

fig. 134 is a side view of a bone fixation device inserted into two unreduced bone segments according to an aspect of the present invention;

FIG. 135 is a side view of a bone fixation device inserted into two reduced bone segments in a flexed condition according to an aspect of the present invention;

FIG. 136 is a graph of the compressive force loaded over distance by the device according to the present invention relative to a standard screw;

FIG. 137 is a partial side view of a portion of a cutback pattern of a bone fixation device having a helically shaped expandable section in an unexpanded state, according to an aspect of the present invention;

FIG. 138 is a partial side view of a bone fixation device having an unthreaded, helically expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 139 is a partial side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 140 is a side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 141 is a side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 142 is a side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 143 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 144 is an enlarged scale detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a helically expandable section without threads in accordance with an aspect of the present invention, wherein the torsional engagement feature is in an unexpanded state;

FIG. 145 is a partial side view of a bone fixation device having an unthreaded, helically expandable section with a torsional engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 146 is a side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 147 is a side view of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 148 is a side view of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 149 is a side view of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 150 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 151 is a partial side view scaling detail of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 152 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

fig. 153 is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 154 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 155 is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 156 is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 157 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 158 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

Fig. 159 is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 160 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 161 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 162 is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 163 is a partial side view of a portion of a cut groove pattern of a bone fixation device according to the present invention having a non-threaded sinusoidally expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 164 is a partial detailed side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded sinusoidal expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 165 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section with a trapezoidal torsional engagement feature and an axial length engagement feature in an unexpanded state according to an aspect of the present invention;

FIG. 166 is a partial detailed side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section with a trapezoidal torsional engagement feature and an axial length engagement feature in an unexpanded state according to an aspect of the present invention;

FIG. 167 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 167A is a partial detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 167B is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length limiting feature in an expanded state in accordance with an aspect of the present invention;

FIG. 167C is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168A is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature in a deformed, expanded state in accordance with an aspect of the present invention;

FIG. 168B is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168C is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168D is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168E is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state in accordance with an aspect of the present invention;

FIG. 168F is a cross-sectional view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168G is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 168H is a partial side view of a portion of a cutback pattern of a bone fixation device having a fixed helically shaped expandable section with a torsional engagement feature and an axial length engagement feature in a transitional state in accordance with an aspect of the present invention;

FIG. 168I is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a deformed, expanded state in accordance with an aspect of the present invention;

FIG. 169 is a scaled detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature in an expanded state according to an aspect of the present invention;

fig. 169A is a scaled detail of a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature in a deformed, expanded state, according to an aspect of the present invention;

FIG. 169B is a partial side view scaling detail of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 169C is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length engagement feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 170 is a partial side view of a bone fixation device having an unthreaded expandable section in a non-expanded state according to an aspect of the present invention;

FIG. 171 is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 172 is a partial side view of a bone fixation device having an unthreaded axially sinusoidal expandable section in a non-expanded state in accordance with an aspect of the present invention;

Fig. 173 is a partial side view of a bone fixation device having an unthreaded, axially sinusoidal expandable section in an expanded state according to an aspect of the present invention;

FIG. 174 is a partial side view of a bone fixation device having a non-threaded axially angled expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 175 is a partial side view of a bone fixation device having an axially angled expandable section without threads in an expanded state according to an aspect of the present invention;

FIG. 176 is a partial side view of a bone fixation device having an unthreaded expandable section in a non-expanded state according to an aspect of the present invention;

FIG. 177 is an enlarged, fragmentary, detailed side view of a bone fixation device having an unthreaded expandable section in an expanded state according to an aspect of the present invention;

FIG. 178 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state in accordance with an aspect of the present invention;

FIG. 179 is a side view of a bone fixation device inserted into two reduced bone segments in accordance with an aspect of the present invention;

FIG. 180 is a side view of a bone fixation device inserted into two reduced bone segments in an expanded state according to an aspect of the present invention;

FIG. 181 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state according to an aspect of the present invention;

FIG. 182 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state according to an aspect of the present invention;

FIG. 183 is a side view of a bone fixation device inserted into two reduced bone segments in a non-expanded state according to an aspect of the present invention;

fig. 184 is a side view of a bone fixation device in an expanded state according to an aspect of the present invention;

FIG. 185 is a partial cross-sectional side view of a bone fixation device in an expanded state according to an aspect of the present invention;

fig. 186 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

FIG. 187 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

fig. 188 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

FIG. 189 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

Fig. 190 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

fig. 191 is an isometric view of a bone fixation spring element arrangement in accordance with an aspect of the present invention;

FIG. 192 is a side view of a bone fixation device reduced to practice in a non-expanded state with a non-threaded helically expandable section having a torsional engagement feature in accordance with an aspect of the present invention;

FIG. 193 is a partial side view of a bone fixation device reduced to practice in a non-expanded state with a non-threaded helically expandable section having a torsional engagement feature in accordance with an aspect of the present invention;

FIG. 194 is a graph with data from the inventive device reduced to practice compressive forces unloaded over a range of distances relative to a standard screw;

FIG. 195 is a partial perspective cross-sectional view of a bone fixation device assembly having a threaded distal end section and an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 196 is a partial side cross-sectional view of a bone fixation device having a helically expandable section without threads in an unexpanded state in accordance with an aspect of the present invention;

FIG. 197 is a partial side cross-sectional view of a bone fixation device having a non-threaded helical expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 198 is a partial side cross-sectional view of a bone fixation device having a helically expandable section without threads in an unexpanded state in accordance with an aspect of the present invention;

FIG. 199 is a partial cross-sectional view of a bone fixation device having an unthreaded expandable section in an unexpanded state according to an aspect of the present invention;

FIG. 200 is a partial cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 201 is a partial cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 202 is a partial cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 203 is a partial cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 204 is a cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 205 is a cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 206 is a cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 207 is a cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 208 is a cross-sectional view of a bone fixation device having an unthreaded expandable section in a non-expanded state in accordance with an aspect of the present invention;

FIG. 209 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 210 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 211 is a flow chart illustrating one embodiment of a method for clinical application of a bone fixation device in accordance with the present invention;

FIG. 212 is a partial side view of a cutting pattern of a known device;

FIG. 213 is a graph of the reaction force against displacement under axial and torsional loads for several embodiments of the present invention illustrated in FIGS. 214, 215, 216 and 217;

FIG. 214 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

Fig. 214A is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded helically shaped expandable section with a torsional engagement feature and an axial length limiting feature in an expanded state in accordance with an aspect of the present invention;

fig. 214B is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a laterally flexed condition according to an aspect of the present invention;

fig. 214C is a partial cross-sectional side view of a portion of a cutback pattern of a bone fixation device having an unthreaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a laterally flexed condition according to an aspect of the present invention;

FIG. 215 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

fig. 215A is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in an expanded state in accordance with an aspect of the present invention;

FIG. 216 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section having a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 216A is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in an expanded state in accordance with an aspect of the present invention;

FIG. 216B is a partial side view of a portion of a cutback pattern of a bone fixation device having an unthreaded helically expandable section with a torsional engagement feature and an axial length limiting feature in a laterally flexed condition according to an aspect of the present invention;

FIG. 216C is a partial cross-sectional side view of a portion of a cutback pattern of a bone fixation device having an unthreaded, helically-expandable section with a torsional engagement feature and an axial length limiting feature in a laterally flexed condition according to an aspect of the present invention;

FIG. 217 is a partial side view of a portion of a cut groove pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state in accordance with an aspect of the present invention;

FIG. 217A is a partial side view of a portion of a cut groove pattern of a bone fixation device having a helically shaped, non-threaded expandable section with a torsional engagement feature and an axial length limiting feature in an expanded state in accordance with an aspect of the present invention;

FIG. 218 represents a commercially available device according to ASTM F543-17 standard specifications and a test device for metallic medical bone screws based on ISO 5835, ISO 6475, and ISO 9268 with data collected according to embodiments described herein;

FIG. 219 represents data collected on the examples described herein according to ASTM F543-17 standard specification and test method for metallic medical bone screws according to ASTM F543-17, ISO 6475 and ISO 9268;

FIG. 220 represents data collected from an industrially available device according to ISO 5835, ISO based on Standard Specifications and test methods for metallic medical bone screws according to the ASTM F543-17 Standard, according to embodiments described herein;

FIG. 221 represents data collected in the examples described herein for an ASTM F543-17 standard specification and test method for metallic medical bone screws according to ISO 5835, ISO and commercially available devices;

FIG. 222 represents data collected in the examples described herein according to ISO 5835, ASTM F543-17 Standard Specification and test methods for ASTM F543-17 metallic medical bone screws according to ISO and commercially available devices;

FIG. 223 represents a commercially available device according to ASTM F543-17 standard specification and a testing device for metallic medical bone screws based on ISO 5835, ISO 6475, and ISO 9268 that collects data according to embodiments described herein;

FIG. 224 represents a commercially available device in the industry according to ASTM F543-17 standard specifications and a test device for metallic medical bone screws based on ISO 5835, ISO 6475, and ISO 9268 with data collected according to embodiments described herein;

fig. 225 represents data collected on the embodiments depicted herein according to ASTM F543-17 standard specifications and commercially available equipment and ISO 5835, ISO metallic medical bone screw design and testing methods.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Specific embodiments of the present invention will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; the present invention is not limited to the disclosed embodiments; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbering represents like elements.

Embodiments of devices and methods that provide an active compression system that compresses and secures bone segments are described herein. In one embodiment of the invention, the structure of the orthopaedic bone system is preloaded prior to insertion, or effectively loaded during insertion into the desired orthopaedic site to provide active compression over the entire fracture post-operatively, or post-operatively loaded after implantation of the device. In some embodiments, the active compression system includes an elastically expandable section. Further, the distal and proximal portions are connected to each other by an elastic, expandable portion configured to be tensioned and to provide active compression between the distal and proximal portions.

In certain embodiments, a surgical procedure is provided that employs potentially fewer steps than current active compression screws, may vary in length by at least 0-6 millimeters (mm), and is capable of providing an axial force of 0-1000 newtons (N), which may or may not be compression over time.

Furthermore, the embodiments described herein, as well as other embodiments, provide a unitary body construction, possibly manufactured by common manufacturing techniques, which may result in lower cost of goods than current active compression platforms, and possibly a reduction in design to at least 2.0 mm screws.

This application references US 8,048,134B2, filed on 6/4/2007, and international application PCT/US2015/063472, filed on 2/12/2015, which are incorporated herein by reference in their entirety.

As used herein, the terms set forth below have the following relevant definitions known to those skilled in the art. "thread pitch" is the distance from one point on a thread to the corresponding point on the next thread, measured parallel to the longitudinal axis of the screw. "pitch diameter" on a straight thread refers to the diameter of an imaginary cylinder whose surface passes through the thread such that the width of the thread and the spacing between the threads are equal. The "pitch diameter" on a tapered thread, i.e. the diameter at a given distance from a reference plane perpendicular to the imaginary cone axis, will have its surface passing through the thread at such a point that the width of the thread is equal to the width of the space cut by the cone surface.

"lead" refers to the distance a thread measures parallel to an axis when making one revolution. On a single-thread screw, the lead and pitch are the same. On a double-thread screw, the lead is twice the pitch; on a three-thread screw, the lead is three times the pitch. The "major diameter" is the maximum diameter of the external or internal thread. The "minor diameter" is the smallest diameter of the thread. The "root" is the threaded surface corresponding to the minor diameter of the external thread and the major diameter of the internal thread. Also defined as the bottom surface connecting two adjacent thread flanks. The engagement features or ends of the screws of the present invention may have any such features to help facilitate clinical treatment, such as self-cutting, self-tapping, anti-rotation and/or anti-back-out features, reverse cutting threads, and contours or features that help lock the component to the plate, rod, nail, or other screw.

Generally, disclosed herein are bone fixation or connection devices that may include a first portion, a second portion, and at least one axial tensioning portion or feature. As used herein, the terms "bone fixation device," "bone fusion device," "medical device," "connecting member," and "implant" are used interchangeably as they essentially describe the same device. As used herein, the terms "expand," "load," "force," "stretch," and "lengthen" are used interchangeably as they describe essentially the same feature or condition. As used herein, the terms "relax", "unload", "reduce", "collapse" and "shorten" may be used interchangeably as they describe essentially the same feature or condition. Likewise, the terms "active", "dynamic" and "non-passive" are used interchangeably and have the same meaning, i.e. applying a continuous force upon loading, and these terms are used interchangeably.

Furthermore, the respective insertion tool or tools may also be referred to as "tools" or "instruments," and these terms may be used interchangeably. In this detailed description and in the following claims, the terms "proximal", "distal", "front", "rear", "medial", "lateral", "upper" and "lower" are defined according to their standard usage in indicating a particular location of a bone or implant according to the relative position or reference orientation of the natural bone. For example, "proximal" refers to the portion of the implant furthest from the insertion end, while "distal" refers to the portion of the implant closest to the insertion end. With regard to directional terminology, "front" refers to a direction toward the front of the body, "rear" refers to a direction toward the rear of the body, "center" refers to a direction toward the midline of the body, "lateral" refers to a direction toward the side of the body or away from the midline of the body, "up" refers to an upward direction, and "down" refers to a direction below another object or structure.

In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the active compression orthopedic screw systems or devices and methods of the present invention. One skilled in the relevant art will recognize, however, that the present exemplary systems and methods can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures associated with orthopedic screw systems have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the present exemplary embodiments.

As used in this specification and the appended claims, the terms central member, deformable member, and expandable member should be construed to include any number of members having a square, circular, or rectangular cross-section configured to store energy. Furthermore, as used herein, the term "slidably coupled" should be broadly construed to include any coupling configuration that allows relative translation between two members, where the translation may be linear, non-linear, or rotational.

Unless the context requires otherwise, in the following description and claims, the word "comprise" and variations such as "comprises" and "comprising" are to be interpreted openly, including the inclusive meaning of "including but not limited to". Reference in the specification to "one embodiment," "certain embodiments," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment. Furthermore, the particular disclosed features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms "comprises" (and any form of comprising, such as "comprises" and "comprising)", "comprising" (and any form of possessing, such as "has" and "having)", "comprising" (and any form of containing, such as "comprises" and "containing") and "containing" (and any form of containing, such as "containing" and "containing)" are open-linked verbs. As a result, a method or apparatus that "comprises," "has," "includes" or "contains" one or more steps or elements has those one or more steps or elements, but is not limited to having only one or more steps or elements. Likewise, the terms "comprising," "having," "including," or "containing" one or more features have the features or steps of a method or apparatus, but are not limited to having only those feature or features. Further, a device or structure configured in a certain way is configured in at least this way, but may also be configured in ways not listed.

The present active compression orthopaedic engagement member or screw system will be described herein in the context of a bone screw assembly configured to stabilize bone for ease of explanation only. It will be apparent to those skilled in the art in view of the disclosure herein that the methods and structures disclosed herein are intended for use with any of a variety of bones, fractures, and fusions. For example, the bone fixation devices of the present systems and methods are suitable for use in a variety of fractures and osteotomies of the hand, such as interphalangeal and metacarpal joint fixation, transverse finger and metacarpal fracture fixation, spiral finger and metacarpal fracture fixation, oblique finger and metacarpal fracture fixation, intercondylar finger and metacarpal fracture fixation, phalangeal and metacarpal osteotomy fixation, and other methods known in the art.

Various phalangeal and metatarsal osteotomies, as well as foot fractures and fusions, may also be stabilized using the bone fixation devices of the present systems and methods. These include, inter alia, distal metaphyseal osteotomies such as those described by Austin and Reverdin-Laird, base wedge osteotomies, oblique diaphyses, finger arthrodesis, and a variety of other methods known to those skilled in the art. Fibular and tibial ankle fractures, fractures of the distal tibia, and other fractures of the leg bone may also be fixed and stabilized using the present exemplary system and method. Each of the foregoing may be treated in accordance with the present systems and methods by passing the active compression screw systems disclosed herein through a first bone component, through a bone fracture, and into a second bone component to fix the bone fracture.

One such embodiment of the apparatus and method for providing an active compression system to compress and fix bone segments has a unitary, continuous structure and generates a compressive force by driving a screw-like body into the bone segments to be fused. According to one embodiment, an orthopaedic bone fixation device for actively compressing a plurality of bone segments includes: a first segment or portion at the distal end of the device, a second segment or portion at the proximal end of the device, and an elastic segment or portion having first and second ends. The first end of the elastic segment is coupled to the first segment, and the second end of the elastic segment is coupled to the second member, elastic member, or elastic portion in an expanded state, configured to apply a force that pulls the first member and the second member or portion together. The resilient member and the distal and proximal segments or portions are constructed as a unitary continuous member or structure.

An implant for inserting and stabilizing bone material having first and second regions is disclosed. The implant includes a shaft including a longitudinal axis, a proximal end portion, an expandable central section or portion, and a distal end portion. The proximal and distal portions may have proximal and distal threads formed thereon, respectively. The proximal and distal threads have smaller and larger diameters, respectively. The short diameter of the proximal thread may or may not be equal to the long diameter of the distal thread. The shaft of the implant may have an expandable medial side portion disposed between the proximal and distal ends without threads that separate the proximal and distal end portions and that may vary in length. When the screw implant is inserted into the bone material by rotation, the proximal and distal end portions engage the first and second regions, respectively, to provide compression therebetween, which force may then elongate or may not elongate the expandable inner portion.

Advances in the state of bone fusion and bone fixation devices and implants, as well as surgical treatments associated with the clinical manifestations of damaged or fractured bone in vivo are expected to be desirable. Active compression, in addition to resisting bone resorption, also helps to eliminate angular misalignment. Certain embodiments of the present invention provide a bone fixation device or bone fusion device for treating a patient having diseased or damaged bone that includes a member having an expandable compression feature. In one aspect, the invention provides a bone fixation device that includes a member and at least one axially and/or radially deformable feature or portion positioned between a distal end and a proximal end.

According to one embodiment, the implant of the invention is a compression implant and is a bone screw. When the bone screw is screwed into the two regions of bone, the distal threaded portion and the proximal threaded portion may threadably engage each of the two regions of bone and stabilize the bone and potentially provide an axial force to elongate the central portion, respectively.

In some embodiments, the bone screw device is cannulated throughout its length to allow for use with a suitable guide wire and cannulated tool for drilling and driving. In another embodiment, to compress two spaced materials, such as bone fragments, the primary and secondary screws may be pre-drilled and a screwdriver may be used to tighten the screws through the fracture line, whether the central portion is elongated or not. Once the screw segments are in place, a separate driver may be used to further rotate or rotate the distal screw member into place and cause compression of the bone fragments and elongation of the central expandable segment.

The systems and methods of the present invention provide an orthopedic screw system configured to provide a post-operative "active" compressive force for fusion on an engaged bone segment. As used herein, the term "active" should be interpreted to refer to a system configured to provide an active compressive force. Rather than a "passive" fastener that generates compressive forces but does not itself provide dynamic compressive forces. The elongation of the device of the present invention provides continuous axial compression on the bone segments to which it is engaged until the elongation is reduced to its resting or non-expanded state. The bone tissue and device will remain in dynamic interaction with the force applied by the device until the bone then yields or remodels to a zero or reduced stress relationship between the tissue and device.

In certain embodiments, the devices of the present invention are stretched or expandable in length under sufficient axial load. Thus, the device can maintain a certain amount of compressive force at the fusion surface even with the collapse or collapse of bone at the fusion surface over time. The dynamic or axial compression of the transverse osteotomy has been shown to increase torsional stability and torque capacity at the fracture site compared to locking stiffness control.

The dynamic nature of the active compression design of the present invention allows for controlled axial compression at the fusion surface, which may result in a reduction in stress shielding. In contrast, the solid design of the known devices and the threaded screw and nail design are statically locked, thus creating a greater degree of stress shielding. This reduction in stress shielding of the present invention is beneficial for improved bone healing and fusion.

Embodiments of the elongated compression section of the present invention represent a fixation device that can provide active compression to a fixation structure over a period of time. The forces exerted on the bone may have the ability to accommodate changes that occur due to bone dehiscence, migration, and/or resorption. The elongated compression section of the device of the present invention creates a dynamic or residual compressive force at the fusion interface. The dynamic force may be adjusted over time to accommodate any potential gaps due to surface changes, osteoporosis, surgeon application, premature loading, or the presence of bone graft material.

According to another embodiment, the active compression screw system according to the present invention may also be used to attach tissues or structures to bone, for example during ligament reattachment and other soft tissue attachment procedures. The fixation device may also be used to attach sutures to bone, for example in any of a variety of tissue suspension procedures. For example, according to one embodiment, soft tissue such as a capsule, tendon or ligament may be secured to bone by using the device of the present invention.

The devices and methods of the present invention may also be used to attach synthetic materials such as mesh to bone, or allograft materials such as tensor fascia to bone. In doing so, retention of material may be achieved by the enlarged head of the active compression orthopedic screw system shown in the figures to accept sutures or other material to facilitate such attachment. The ability to actively compress the orthopedic screw of the present invention prevents the screw from loosening, thereby reducing the likelihood of premature release of the attached tissue or structure from the bone. The ability of the screw to vary in length may further protect the bone from the stresses of the applied tension, and therefore, in this example, the stresses shield the connection mechanism with the bone, better achieving better or stronger or more consistent long-term retention of the bone thread interface.

The combined features of the screw implant of the present invention may result in improved compression performance as the screw will more efficiently produce bone or tissue compression. Such screw implants are useful in many types of surgical procedures, such as osteotomies involving two separate bones of the same piece, arthrodesis to join two or more bones together, and implant fixation by screws to secure bones and other materials in place.

According to another embodiment, the length of the expandable or deformable member is increased by an axial force in a stretched, expanded, loaded or stressed state. The axial force causes deflection of struts formed in the expandable or deformable member or portion to achieve an increased separation distance between the struts, and then an overall increase in the length of the member from the original unexpanded or unstretched state. The distance or amount of axial translation may vary from small to large displacements, depending on a number of variables and desired performance characteristics.

These performance characteristic variables include, but are not limited to: the width of the expandable or deformable member or portion of the strut, the length of the strut, the radius of the end slots, the width of the slots, an outer diameter of the expandable or deformable member, an inner diameter of the expandable or deformable member, a number of slots along the expandable or deformable radius, a shape of the slots, an angle of the slots, a number of slots along an axial length of the expandable or deformable member, the number of expandable or deformable members, the number of layers of expandable or deformable members, the configuration of the plurality of members, the length of the expandable or deformable component or section along the pattern of slots, the location of the beginning and ending slots along its length, the overall length of the expandable or deformable member, the material, the surface treatment of the material forming the expandable or deformable portion or member, the surface quality, the machined profile of the expandable or deformable member, and the ratio and/or relationship of these variables to one another. The terms perforations and slits and their plural forms are used interchangeably herein.

The desired characteristics to be controlled in embodiments of the present invention may include, but are not limited to: the amount of axial force applied to restore or attain length, the amount of axial force applied to increase axial length or to stretch or load the member, the amount of length change that is variable along the axial position of the member, the ratio of the amount of force change to the length change, the radial bending stiffness of the entire member along the axis, the torsional stiffness, the separation of the individual strut members, the elastic limit of the material, engagement in bone tissue, insertion force of the component into the bone, the mobility of the component, migration of the component in/through bone tissue, resistance of the component to migration in bone tissue, the biocompatibility of the member, ease of use of the member in procedures, ease of manufacture of the member, the cost of the member, the number of elements used to construct the member, and the manufacturing process used to construct the member.

Many variables are involved in the perforation or cutting characteristics that may affect the axial tension, bending stiffness and torsional stiffness of the structure. The perforation or cutting features of the expandable or deformable portion of the device of the present invention may be arranged in an infinite number of cell designs, such as those described and including but not limited to. Diamond, wave, non-uniform shape, sinusoidal, slot, oval or circular. Illustrative examples of some of these possible embodiments can be seen at least in fig. 88-112. These perforation or slot patterns may repeat or vary lengthwise, and multiple shapes and sizes may be combined in the same configuration lengthwise or around the circumference. The size of the struts may vary along the length. The cross-section of the member may also have an infinite number of arrangements of cell designs, such as those that have been demonstrated in the prior art and known to those skilled in the art, including but not limited to: circular, square, oval, etc., which features and dimensions may vary in wall thickness and cross-section along the length of the device of the present invention.

In some embodiments, increasing strut length increases the amount of deformation under a given load condition. This is advantageous because the increased length change accommodates larger changes in bone tissue over time. The amount of force applied as compression can then be reduced, which can be a desired characteristic, depending on the desired load distribution. The radius of the end undercut affects the strain of the strut and increases or decreases the amount of recoverable deformation. The width of the perforations or slits may promote more or less construction flexibility. This width also affects the manufacturing process, making laser cutting of wider slots (e.g., machine milling) or narrow slots possible.

The outer diameter of the expandable or deformable portion or member can affect the overall stiffness and axial tension of the structure by increasing or decreasing the amount of structural material involved as well as varying the bending moment. The inner diameter of the expandable or deformable portion or member may affect the overall stiffness and axial tension of the construction by increasing or decreasing the amount of structural material involved, which may also affect the manufacturing process used to manufacture the construction. The inner diameter may also affect the assembly members or other features used to facilitate the application method of embodiments of the present invention.

The number of slots along the radius of the member also affects the axial tension generated by the member, and/or the bending stiffness of the construction. The use of more shorter length grooves or less longer length grooves or grooves that are unevenly distributed around the radius may promote the desired behavior of the construction. The shape of the perforations or slits can affect the axial tension, bending stiffness and torsional stiffness of the structure by affecting local deformation of the structure under load. The angles of the cuts relative to the axis of the member and to the radius of the construct may promote different bending behaviors. The number of slots along the axial length of the member, the density of the slots, the pattern of the slots, the location of the slots along the length, and the total length of the area covered by the slots also affect the desired performance of embodiments of the present invention. The greater the number of slots along the length, the greater the variation in length for a given design. The more slots on the circumference, the less length variation for a given design and length. Theoretically, the number of grooves formed around the circumference defines the number of spring elements parallel to the structure. Assuming a constant strut width, the greater the number or number of cells on the circumference, the higher the spring constant per spring, due to the short strut length available. More cells along the length effectively reduce the spring constant, allowing the structure to increase the stretched length.

The use of multiple expandable or deformable portions or multiple members helps achieve the desired design intent. For example, by employing nested or layered expandable or deformable portions or members, flexible and non-flexible layers may be used concentrically together to create axially flexible and flexurally rigid configurations, and vice versa. Embodiments of the invention employ a unitary member, or may be constructed of several different members, and joined together in a rigid fashion or in a manner that leaves freedom between multiple bodies. The length of these individual members can affect performance by increasing or decreasing the required behavior. The position of axially, outer or inner layered components may also be used to control the behavior of embodiments of the present invention.

Materials may also be used as variables; elastic, rigid, absorbable, biocompatible, and any other material known to those skilled in the art may be used alone or in combination with other materials to create the desired set of characteristics. Surface treatment of the material can also have an effect on the behavior of the structure. The ratio and/or relationship of these variables to each other can be varied by one of ordinary skill in the art in light of the spirit of this disclosure, and all combinations are considered to be encompassed by this disclosure.

The inventive embodiments described in further detail herein and the variables described and illustrated in any one of the figures may be used with all other examples that may be exemplary, captured in the text or known to those of skill in the art.

Another embodiment is the ability of the axial tension members to increase and/or decrease in radial diameter from the central axis. This function may also yield additional clinical benefits by increasing the ease of tissue interfacing or surgery. The ability to adjust all of these variables to produce the desired axial or longitudinal tension over a given length does not exceed the resistance of the tip retention feature in the tissue for an extended period of time, which will help promote healing.

The present invention includes embodiments of an apparatus and method that provides an active compression system that compresses and secures bone segments; has a single continuous structure; by driving a screw-like body into a bone segment; compression forces in excess of 0.5mm may be provided, and in some embodiments, bone resorption forces in excess of 6mm may be absorbed; axial compression force of 0-200N can be provided; compressive axial forces may be transmitted for more than 1 hour, and possibly up to 48 hours or more after transmission to the bone; different amounts of axial compression force can be transmitted over time; can transmit selected axial compression force; different amounts of axial compression force can be transmitted over time; the diameter may be 2-20 mm.

In certain embodiments, the inventive method includes driving a screw-like body into a bone segment and then activating an axial compression force.

In certain embodiments, the inventive method includes driving a screw-like body into a bone segment and delivering the body into the bone segment, the shaft segment having an axial force generating member that is substantially the entire length of the body.

In certain embodiments, the method of the present invention includes driving a screw-like body into a bone segment and delivering the body into the bone segment, the bone segment having an axial force generating member in a defined region of a length of the body; has a single continuous structure and is conveyed by a K line; or have an integral, one-piece, continuous structure; or has a hollow structure; or by delivering the body into a bone segment having an axial force generating member that utilizes a piercing or cutting feature to achieve axial tension.

The devices and methods of the present invention provide an active compression system that compresses and secures bone segments; has a single continuous structure; by driving a screw-like body into the bone segments. The screw-like body has an axial force generating member that utilizes a piercing or cutting feature to achieve axial tension and a threaded region of the body and engagement of the threaded region with the bone to preload the axial tension. Alternatively, the screw-like body has an axial force generating member that utilizes a piercing or cutting feature to obtain axial tension and a delivery mechanism to generate axial pretension. Alternatively, the helical body has an axial force generating member that utilizes a piercing or cutting feature to achieve axial tension and an internal member to generate axial pretension.

The devices and methods of the present invention provide an active compression system that compresses and secures bone segments in a unitary abutment structure having an axial force generating member that utilizes a piercing or cutting feature to achieve axial tension and uses an absorbable material. Alternatively, the axial force generating member utilizes a structure made of shape memory alloy SMA or other materials commonly used in the manufacture of implant devices.

The devices and methods of the present invention provide an active compression system that compresses and secures bone segments that have the ability to elastically deform along a central axis beyond the ability that a solid screw of any material may elastically deform. Such deformability allows clinical applications beyond currently available options or solutions as well as clinical applications that may benefit from a tissue fixation device that provides an axially moving configuration.

The apparatus and method of the present invention provide screws designed to bend or transmit torque around corners.

The apparatus and method of the present invention provides screws that are formed in a curved, bent or helical shape and are mounted or delivered in a straight shape.

The apparatus and method of the present invention provide screws made of PEEK or other materials.

The apparatus and method of the present invention provides a screw that is machined in an elongated state and then formed into a shortened state.

The apparatus and method of the present invention provide a locking feature on the screw head to work with the plate, rod and/or nail.

The devices and methods of the present invention provide screw design features that may or may not be used with plates, rods, and/or nails.

The devices and methods of the present invention provide screws for use in spinal applications.

The devices and methods of the present invention provide a screw formed with an expanded central portion that is larger than the distal and proximal threads.

The apparatus and methods of the present invention provide solid screws, cannulated screws, and cap screws.

The apparatus and method of the present invention provide a passive thread feature to prevent back-out, reverse cutting of the thread.

The devices and methods of the present invention provide a screw having a central portion larger than the distal end, the screw capable of applying torque at the distal end; a driver is inserted all the way through the proximal threads and the central portion into the distal socket to assist in torquing the device.

The devices and methods of the present invention provide an external or internal spring element to increase and/or store and/or maintain a pulling force that in turn creates or provides a compressive force between two or more tissue segments.

The apparatus and method of the present invention provide a hybrid screw; structures made from a variety of materials, such as but not limited to polymers plus metals, combine different alloys into the structure of the embodiments.

The devices and methods of the present invention provide a fastener that does not have a significantly enlarged proximal head and/or has a continuous thread diameter throughout the length of the screw, where the proximal and distal threads may have the same diameter.

Additionally, the present invention provides methods of assembling a bone fixation device.

In addition, the present invention provides methods of compressing bone segments using the bone fixation devices.

The devices and methods of the present invention provide the ability to continuously apply compressive forces to bone segments over the distance or length over which the embodiment is initially stretched or extended. The mechanism to provide such expansion and contraction or length change includes a continuous winding member spanning the length of the expandable section. The winding member comprises a single winding around the entire circumference. The winding member includes a plurality of winding members spanning the length of the expandable segment. The wound member is shaped and functions like a helical coil spring of rectangular cross-section. The pitch of the winding cut pattern is directly related to the spring constant of the flared portion.

The devices and methods of the present invention provide the ability to continuously apply compressive forces to bone segments over the distance or length over which the embodiment is initially stretched or extended. Mechanisms to provide such expansion and contraction or length change include continuous winding members or struts across the length of the expandable section. The wrap has been integrated into any orthopedic screw design. These screws have a standard head, a threaded head, a self-tapping and cutting thread profile, a cannulated screw, a screw of any diameter, a screw of any length, for example a screw of 2mm diameter, a screw of 12mm diameter, a screw of 20mm length, a screw of 300mm length.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. The mechanism to provide such expansion and contraction or length change includes a continuous winding member spanning the length of the expandable section. The winding portion is a continuous body having a distal threaded portion of the body and a proximal head.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. The mechanism to provide such expansion and contraction or length change includes a continuous winding member spanning the length of the expandable section. The winding portion is a continuous body having a distal threaded portion of the body and a proximal head. The winding direction is the same as the thread direction on the distal end. The winding direction is opposite to the direction of the thread on the distal end.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. The distance is limited by a limiting feature. The length limiting feature is present on the wrap or strut member. The length limiting feature is present on the rotational engagement member. The length limiting feature is present on the leading edge of the wrapping member. The length limiting feature is present on the trailing edge of the wrapping member. The length limiting feature is present on the leading edge of the rotational engagement member. The length limiting feature is present on the trailing edge of the rotating engagement member. The length limiting feature is integrated into the rotational engagement feature. The length limiting member has a mechanical engagement. The length limiting feature has a sliding engagement. The length limiting feature has a wedging engagement. The length limiting feature has a snap-fit engagement. The present invention has 1 to 100 length limiting features along the expandable section. The present invention has 1 to 100 length limiting features along the circumference of the body. The present invention has length limiting features spaced in a uniform pattern along the circumference of the body. The present invention has length limiting features spaced in various patterns along the circumference of the body.

The devices and methods of the present invention provide the ability to continuously apply compressive force to bone segments over a distance or length over which the embodiment is initially stretched or elongated. This variation in length may exceed 20% of the overall construct length. The distance of application of the force may range from 0-20% of the total length of the body and may be set by design.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. This distance is limited by design. The limiting feature allows a compressive force to be applied to the bone segments that is greater than the spring force of the expansion mechanism. This is commonly referred to as preloading. An example of this is that the spring mechanism may apply a constant or variable 50N compression force to the bone segments over a distance of 3 mm. Further engagement of the threads with the bone tissue after the screw has been extended 3mm may result in a compressive force of 200N between the bone segments. Since bone remodels or is absorbed during the healing process due to compressive loading, a force of 200N will break down in less than 1mm of bone resorption, and the resilience of the expandable mechanism will load the bone with a force of 50N until the 3mm of tension is reduced to 0mm, which may or may not occur.

The devices and methods of the present invention provide the ability to continuously apply compressive forces to bone segments over a distance or length over which the embodiment is initially stretched or stretched, the stretched length of which is limited by the interference mechanism.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length, wherein this embodiment is initially stretched or elongated, with a rotational engagement feature that limits the amount of rotation along the length of the expandable section. These rotational engagement features may enable the length of the expansion mechanism to be varied. These rotational engagement features may resist length changes of the expansion mechanism. These rotational engagement features may limit the change in rotational position of the expansion mechanism during loading.

The devices and methods of the present invention provide the ability to continuously apply compressive force to bone segments over a distance or length at which the embodiment is initially stretched or lengthened with a stress-relieved cutting pattern to allow for large deformations.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over the distance or length that the embodiment is initially compressed or shortened. This distance is limited by design. The limiting feature allows a compressive force to be applied to the bone segments that is greater than the spring force of the expansion mechanism. This is commonly referred to as preloading.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over the distance or length that the embodiment is initially compressed or shortened. This distance is limited by design. The force generating member is a compression spring. The force generating member is a compression washer. The force generating member is a compression wave spring. The spring mechanism is located on the exterior of the screw member or bone engaging member. The spring mechanism is located on the bone surface.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over the distance or length that the embodiment is initially compressed or shortened. This distance is limited by design. The force generating member is a compression spring. The force generating member is a compression washer. The force generating member is a compression wave spring.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially compressed or shortened. This distance is limited by design. The force generating member is a compression spring. The spring mechanism is located below the bone surface. The spring mechanism is located inside the holding member. The retaining member engages the bone and the spring. The spring force is transmitted through the head of the screw to the distal bone segment.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. This distance is limited by design. The spring force is transmitted through the head of the screw to the proximal bone segment. The spring force is transmitted through the distal threads of the screw to the distal bone segment.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. This distance is limited by design. The spring force is transmitted through the head of the screw to the proximal bone segment. The spring force is transmitted through the distal threads of the screw to the distal bone segment. The portion of the attachment means resists bending in the region of the bone segment interface. The portion of the screw extending through the fractured bone ends in the non-expanded portion.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. The flared portion has a pattern of kerfs. The cutting pattern has beam members angled with respect to the axis. The cut pattern beam is shorter than the perimeter of the body. The continuous body of the cut pattern has curved beams and connecting nodes. The curved beam produces a spring force to achieve a therapeutic effect. The cutting pattern of the beams is alternately inclined around the circumference of the body. As the body lengthens, the opposing beam angles diverge from one another. During axial tensile loading, the axial separation distance of the nodes at the two ends of the beam relatively increases. The beam members acting as springs are connected in series as a mechanism.

The devices and methods of the present invention provide the ability to continuously apply a compressive force to a bone segment over a distance or length over which the embodiment is initially stretched or elongated. The flared portion has a slotted pattern. The cutting pattern has beam members angled relative to the axis, similar to a sinusoidal pattern. Under axial tensile loads, the beam members deflect to a smaller angle or deform to a straight configuration. A beam member connected to the body at both ends engages the bone tissue. The beam member has a circumferential support member at the apex of the sinusoidal pattern. The diameter of the beam member decreases from its relative starting diameter. The diameter of the beam member increases from its relative starting diameter. The beam members as springs act in parallel as a mechanism.

The methods and devices of the present invention feature cutting paths that do not intersect the central axis of the body. The method and apparatus of the present invention having cutting features produce an overlap of one edge surface with respect to an adjacent edge surface in a plane or axis that is orthogonal with respect to the central axis. The method and apparatus of the present invention have a variable cutting angle or plane throughout the cutting path relative to a line or plane orthogonal to the central axis.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having a strut or spring wound member characterized by features that substantially limit rotation of the strut or spring wound member about a longitudinal central axis of the device due to torsional forces input to the device along the longitudinal central axis of the device, through or into patient tissue at both longitudinal ends of the device, e.g., bone mass, rate and frequency, substantially the same.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts with a rod or spring wound member having features that limit torsional and/or rotational displacement or deformation of the strut or spring wound member about a longitudinal central axis of the device when the features are placed under rotational and/or axial loads.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members that feature displacement of the device when axial deformation is applied to the device.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members with axial length limiting features having two different slope varying load curves.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members with axial length limiting features that may be designed to limit the amount of deformation at a given load.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having a rod with struts or spring wound members with axial length limiting features that also limit torsional displacement of adjacent struts or spring wound members.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members with features that enable axial translation or deformation up to a predetermined size of the device, such as an axial length or circumference, where the features suddenly resist such deformation.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having a strut or spring wound member characterized in that, regardless of the direction of rotational input applied to the device, the feature limits deformation or deflection of the strut or spring wound member, i.e., has a feature that allows the device to be alternately axially displaced within patient tissue without blocking or binding the device.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members with features that limit torsional rotation without applying axial loads or resistance in both axial directions of the device.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring wound members with features that limit torsional deformation or deformation and increase the overall torsional strength of the device.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having struts or spring-wound members with features that limit axial deflection or deformation and increase the overall axial strength of the device.

Certain embodiments of the present invention provide devices, such as bone fixation devices, having components of struts or spring wound members with features that limit torsional and axial deformation of the device and increase the overall torsional and axial strength of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for designed length-varying elongations of 2mm or greater without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, having features that minimize friction between adjacent features of the device during a designed length change, and having features that limit the length change to within the designed extension, and then resist further axial and torsional loading of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, and have features that limit the length changes to within the designed extension, then resist further axial loading of the device, and have minimal bending.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, then resist further axial loading of the device, and have minimal bending due to the wedge-shaped features.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, and then resist further axial loading of the device, with maximum flexion due to the engagement features being substantially parallel to the longitudinal central axis of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, and then resist further axial loading of the device, with maximum curvature due to the engagement features being substantially parallel to the longitudinal central axis of the device, and having large relief or cut pattern gaps.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, then resist further axial loading of the device, and minimize bending due to smaller ridge or cut pattern gaps.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, then resist further axial loading of the device, and minimize buckling due to small ridge or cut pattern gaps of less than 0.0015 inches.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for minimal friction between adjacent features of the device during design length changes, have features that limit the length changes to the designed extension, then resist further axial loading of the device, and have maximum flexion due to larger ridge or kerf gaps greater than 0.005 inches.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for design length variations of 1mm or greater, 2mm or greater, 3mm or greater, 4mm or greater, 5mm or greater, 6mm or greater, 7mm or greater, 8mm or greater, 9mm or greater, or 10mm or greater without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for design length variations of 2mm or greater, capable of full recovery from axial loads in excess of 1000N with a 0.118 inch shank diameter, without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices that allow for design length variations of 2mm or greater, that can fully recover from torsional loads in excess of 1.7N/m with a 0.118 inch shank diameter without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for a designed length change of 2mm or greater, are capable of full recovery from axial loads in excess of 1000N at 0.11000 inch shank diameters, and apply 20-60N force during contraction of the 2mm length change without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for a change in design length with the ability to fully recover from axial loading of a solid shaft screw equal to an equiaxed diameter and apply a design force suitable to promote optimal bone healing during contraction of the change in length without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for a change in design length with the ability to fully recover from torsional loading of a solid shaft screw equal to an equiaxed diameter and apply the design force during contraction of the change in length to promote optimal bone healing; without creating friction between adjacent features of the device.

Certain embodiments of the present invention provide features of a device, such as a bone screw or fixation device, that are characterized by allowing for variation in design length with equivalent axial and torsional loading capabilities as a solid shaft device of the same equiaxed diameter, and by applying design forces during contraction of the length variation that are adapted to facilitate optimal treatment in a manner that creates minimal friction between adjacent features of the device.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that allow for engineered length changes and are able to fully recover from axial loads that are equivalent to constant diameter solid shaft screws and apply appropriate engineered forces during contraction of the engineered length changes to promote optimal bone healing, which forces may be less than 100N, may be less than 90N, may be less than 80N, may be less than 70N, may be less than 60N, may be less than 50N, may be less than 40N, may be less than 30N, may be less than 20N or may be less than 10N without creating friction between adjacent features of the device.

Depending on the diameter, length of the cut portion, number of features along the length, wall thickness, and feature size, embodiments herein incorporating data ranges may be fully designed for other data ranges.

Certain embodiments of the present invention provide devices, such as bone screws or fixation devices, that are made of a unitary structure, can use axial compression of designed length, and can limit or control torsional, axial, and bending displacements of laser cut features having variable thickness and geometry beyond the beam thickness they produce.

Although embodiments of the present invention have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, and substitutions are possible, without departing from the scope of the invention.

Detailed description of the drawings

Fig. 1-3 depict a representation of one embodiment of the present invention in which a member 100, shown in a contracted or shortened state, is inserted into bone members 101 and 102, and then bone members 101 and 102 are brought or pulled toward each other, providing a compressive axial tension or force. Bone members 101 and 102 may represent a bone that is divided into two pieces or two bones that are to be fused together. The bone may for example be cortical or cancellous bone or both.

In operation, the engagement member 100 is driven into the bone members 101 and 102 by a mechanical instrument, mechanism or tool 103, which provides the force necessary to accomplish this action. The force may be a force that rotates member 100 and applies an axial force to facilitate threading member 100 into bone members 101 and 102. The bone members may or may not be placed in close proximity to each other prior to insertion or placement of the members 100. Bone members 101 and 102 may or may not be pre-drilled with pilot holes to facilitate placement of bone members 101 and 102.

Bone members 101 and 102 may, but need not, have member 104 inserted prior to placement of member 100, depicted here as an axial member such as K-wire. K-wire 104 may be placed to help facilitate fixation of bone members 101 and 102 relative to each other. The K-wire or member 104 may act as an axial alignment guide for the hollow member 100. Member 104 may or may not be over-drilled with a core drill bit as a pre-drilling step to a diameter that facilitates placement of member 100.

In some embodiments, as shown in FIG. 2, the axial length of the component 100 is varied, as shown for component 200. The change in length occurs over all or a portion of the deformable or expandable section 202 of the member 200. This change in length can be imparted to the contracted or shortened member 100 prior to insertion of bone members 101 and 102. Optionally, such length changes may be imparted to the contracted or shortened member 100 during insertion of bone members 101 and 102. Alternatively, such a change in length may be applied to the contracted or shortened member 100 by action or by a force exerted by the delivery mechanism 103 on the contracted or shortened member 100. Alternatively, such a change in length may be applied to the contracted or shortened member 100 by action or by a force exerted by the delivery mechanism 103 on the contracted or shortened member 100 in combination with the insertion resistance exerted by the bone members 101 and 102.

The elongated or axially elongated member 200 shown in fig. 2 exerts a compressive force on bone members 101 and 102 that pulls bone members 101 and 102 toward one another. The elongated member 200 shown in fig. 2 applies force to the bone members 101 and 102 by a mechanism, for example, wherein threads 106 formed on the exterior of the members 100, 200 engage the bone members 101 and 102 and the head 108 of the members 100, 200, and the pitch of the threads 106 act in combination to apply a compressive load or force on the two bone members 101 and 103 to help promote bone healing or fusion.

The elongated member 200 shown in fig. 2 applies a force to the bone members 101 and 102 to apply an active or continuous force over an extended period of time, such as over a period of 1 to 72 hours. The period of time may be the length of time that the force of the elongated member 200 retracts from an extended state, represented as member 200, to a retracted state, represented as member 100. The time of retraction will be controlled in part by the reaction force exerted by the bone members 101 and 102 on the engagement member or threads 106 of the members 100, 200. The time of retraction and associated forces will be further controlled in part by the nature of the bone material that is formed by the members 100, 200 through the threads 106 and, in part, by features that allow the length of the members 100, 200 to be adjusted.

Mechanisms to control the compressive force generated and associated contraction cycle may include, for example, but are not limited to, the amount of force applied to bone members 101 and 102; the amount of bone material engaged by the engagement features of the implant members 100, 200, such as by the threads 106; and the surface area of the interface between the bone members 101 and 102 and the implant members 100, 200. The extended and adjustable period of time that the continuous compressive force is applied to the bone members 101 and 102 promotes healing and/or formation of a fusion or bond 301 of the bone members 101 and 102 together.

In addition to the acute compressive loading created by the member 200, the stored energy or force of the member 200 may also exhibit continuous loading and/or absorption of bone material over time. The stored compression energy or preload force provides a compressive force through the bone elements that aids in the healing or fusion process. The preload may be applied to the splice components 100, 200 in several ways. Pretension can be imparted to members 100, 200 prior to insertion of the pretension into bone members 101 and 102. Pretension can be applied by the action of inserting members 100, 200 into bone members 101 and 102. The engagement features (e.g., threads 106) on the members 100, 200 can operate in such a manner that the tip or distal end 110 of the members 100, 200 advances at a rate that exceeds the rate of advancement of the proximal end or head 103 of the member 100, and thus, will cause an axial force to the member 100 represented by the member 200 and cause elongation thereof, the details of which will be described further herein.

Fig. 3 shows member 300, which represents a relaxed, contracted state of member 200, in which the preload dissipates over time to help promote bonding or healing between bone members 102 and 101. Such unloading may occur over an extended adjustable period of time. This unloading and contraction can occur over or through a few millimeters of bone resorption. As shown in FIG. 3, the fusion 301 between bone members 101 and 102 is greatly facilitated by the retention and sustained compressive forces during healing.

Fig. 4 is a graphical representation of some of the differences between one embodiment of the connecting member of the present invention and a standard screw. The vertical axis represents the compressive force applied to the bone segments in percent. The horizontal axis represents the time or amount of bone resorption or the change in distance of the bone segments. The device of the present invention may exhibit compressive forces over a greater length variation than standard screws or currently available compression screws. This function is directly related to the long time of transmission of compressive forces to the bone in the living tissue environment. The varying length may apply pressure for a longer period of time as the remodeling or absorption of tissue reaches a zero stress state. The figure depicts the difference between a standard screw 401 and an active compression screw 402.

This compressive load, although beneficial for healing, also produces an effect called walf's law, which considers that bone responds to load by increasing density. If the load exceeds that of the physiological specification, and at an acute or concentrated stress point, the bone will remodel in a manner that reduces the stress point to that of the surrounding bone. This happens very quickly using standard screws. The load placed on the bone by using a standard compression screw will be addressed during a brief or severe compression period, since the length of the screw does not change, and thus the amount of remodeling required to address focal length stresses is small and/or limited. The present invention is contrary to this effect in that as the bone remodels, the length of the connecting member of the present invention will continue to change, thereby creating a compressive force that will last for a longer period of time and/or a greater distance of remodeling of the bone tissue.

In general, the reaction force exerted by a spring as it extends from its rest position is approximately proportional to the change in its length. The stiffness or spring constant of the spring is approximately equal to the change in force applied by the spring divided by the change in spring deflection. That is, it is the slope or slope of the force versus deflection curve. The speed of the extension spring is expressed as force divided by distance, such as pounds per inch, lb./in or newtons per meter, N/m. A linear spring is a spring with a linear relationship between force and displacement, which means that force and displacement are directly proportional. The force versus displacement graph of a linear spring will always be a straight line with a constant slope. This phenomenon occurs with typical compression screws. The length of a typical compression screw will not change, or will change only very little. The spring characteristics of a typical compression screw and coil spring mechanism are primarily dependent upon the shear modulus of the material from which the typical compression screw or coil spring is formed.

In contrast, certain embodiments of the devices disclosed herein exhibit non-linear behavior. Non-linear springs have a non-linear relationship between force and displacement. The graph showing the nonlinear spring force versus displacement will be more complex and the slope will change. Based on the strut or beam bending and based on the material properties of the superelastic material, the properties of the spring or deformable portion of the inventive devices disclosed herein produce a force that varies non-linearly with respect to its displacement. The devices and methods of the present invention provide members that exert a compressive force on at least two tissue members through an axial tensile elastic potential energy that is released through a mechanism that utilizes beam bending and material properties of a superelastic material to generate a force that varies non-linearly with displacement.

Fig. 5 and 6 depict another representation of an embodiment of the invention in which bone elements 501 having compressed regions 502 are brought together and compressed over time with a screw member 500. In fig. 5, screw member 500 is shown with deformable portion 602 in an expanded/stretched/loaded/state 604. Fig. 6 shows the deformable portion 602 of the member 500 in a compressed/unexpanded/unloaded state 606, wherein a compressive force is applied to the compressed region 502 of the bone 501 in the direction indicated by arrow 505 as the deformable portion 602 of the screw member 500 transitions from the expanded state 604 to the final compressed state 606.

Figures 7-10 illustrate anatomical structures in which certain embodiments of the present invention may be utilized. The methods and structures disclosed herein are intended for use in any of a variety of bones and fractures. For example, the bone fixation devices of the present exemplary systems and methods may be applied to various fractures and osteotomies of the hand, such as interphalangeal and metacarpal joint fixation, transverse finger and metacarpal fracture fixation, spiral finger and metacarpal fracture fixation, oblique finger and metacarpal fracture fixation, interphalangeal finger and metacarpal fracture fixation, phalangeal and metacarpal osteotomy fixation, and other methods known in the art. Various phalangeal and metatarsal osteotomies and foot fractures may also be stabilized using the bone fixation devices of the present exemplary systems and methods.

These include, inter alia, distal metaphyseal osteotomies such as those described by Austin and Reverdin-Laird, base wedge osteotomies, oblique diaphyses, phalangeal arthrodesis, and a variety of other methods known to those skilled in the art. Fibular and tibial ankle fractures, fractures of the distal tibia, and other fractures of the leg bone may also be fixed and stabilized using the present exemplary system and method. Each of the active compression screw systems disclosed herein may be treated in accordance with the present systems and methods by passing one of the systems through a first bone component, through a fracture, and into a second bone component to fix the fracture.

Fig. 12-15 illustrate certain embodiments of the invention. More particularly, fig. 12 and 14 depict an embodiment of a member 1200 having a deformable portion 1202 in a stretched, expanded, loaded, stressed state 1204, wherein the length 1201 of the member 1200 is increased by an axial force. In contrast, fig. 13 and 15 depict member 1200 having deformable portion 1202 in a contracted, unexpanded, unloaded, unstressed state 1206, wherein length 1205 of member 1200 is reduced relative to length 1201. The axial force causes the struts 1400 to flex, as shown in FIG. 13, to achieve an increased separation distance 1401 between adjacent struts 1400, thereby increasing the length 1201 of the member 1200 relative to the length 1402 shown in FIG. 15, as shown in FIG. 14. The distance or amount of axial translation may vary from small to large displacements, depending on a number of variables and desired performance characteristics.

These performance characteristic variables include, but are not limited to: strut width, strut length, radius of the end slots making up the strut, slot width, outer diameter of the member, inner diameter of the component, number of slots along the component radius, shape of the slots, angle of the slots, number of slots along the axial length of the component, number of members, arrangement of the plurality of members of the layer of the component, slot pattern along the length direction, position of the starting and ending position in the length direction, total length of the component, material, surface treatment of the material, machined profile, ratio and/or relationship of these variables to each other.

The desired characteristics to be controlled in embodiments of the present invention may include, but are not limited to: axial force applied to restore length, axial force to increase axial length or to stretch or load the member, length change amount force change amount along member axial position change as a ratio of length change, bending stiffness of the entire member along the shaft, separation of individual strut members, elastic limit of material, participation in bone tissue, force of member insertion into bone, movability of the member, migration of the member in/through bone tissue, resistance of migration of components in bone tissue, biocompatibility of the member, ease of use of the member in procedures, ease of manufacture of the member, cost of the member, number of elements of which the member is constructed, manufacturing process of the constructed embodiments.

The diameter of the connection member 1200 of the present invention may be 1mm-20mm and the length of the member 1200 may be, for example, from 4mm to over 400 mm. The difference between distance 1201 of stretched configuration 1204 and distance 1206 of upwardly extending member 1200 is in the range of 0.2% -20% or more of the total length of member 1200. As shown in fig. 14 and 15, the variation or difference in lengths 1401 and 1402 between struts 1400 facilitates, in part, the difference between distance 1201 of extended configuration 1204 and distance 1206 of reach member 1200. The variation or difference in length 1401 and 1402 between struts 1400 may be 0.1% to over 200% of the relaxed length 1401. Dimensions are also applicable to other embodiments of the connecting member of the present invention disclosed herein.

Fig. 16-18 depict another embodiment of the present invention. Fig. 17 is a sectional view of the hollow member 1500 along the line a-a shown in fig. 18. Line a-a may also indicate a longitudinal axis through member 1500. Member 1500 is a threaded screw having a slot 1702 machined along the length of deformable portion 1701. The distal end of the screw 1500 has a cutting feature 1803, a tri-lead 1802, a transition region 1801, a single lead tapered head 1800, a driver engagement feature 1700. The drive engagement feature 1700 may employ any conventional fastener interface, such as a flat head, Philips (Philips), hex head, star head, hex lobe, or the like. In certain embodiments, the difference in pitch of the single-start tapered head 1800 and the triple-start thread 1802 may provide the axial force required to stretch the member 1500 when driving the member 1500 into bone. The cross-sectional view of fig. 17 further illustrates that the entire device is a one-piece member. The one-piece member can be manufactured on a single manufacturing machine, thereby greatly reducing the cost of the present embodiment as compared to other active compression screws.

Fig. 19 and 20 illustrate another representation of the member 1500 shown in fig. 16-18. Fig. 20 depicts a stretched configuration 2000 in which the amount of change in length is variable along the length of deformable portion 1701 of member 1500. FIG. 19 depicts a contracted configuration 1900 of deformable portion 1701 of member 1500. In certain embodiments, the deformable portion of the inventive member deforms uniformly along the length of the deformable portion. In certain embodiments, the deformation is variable along the length of the member. The amount or degree of change in length from state 1900 to state 2000 can be affected by the variables previously described herein. The expanded state 2000 may also promote integration of surrounding bone tissue into the device, which may be desirable to help stabilize bone fusion.

The expanded state 2000 may also facilitate deployment of material from the inner diameter to the surrounding bone tissue. Biologies, antibiotics, bone grafts, BMPs, bone cements, drugs, and any other materials used to help promote bone healing may be deployed through the expansion features of member 1500 or the expansion features of any of the embodiments disclosed herein.

Fig. 21, 22, 23 and 24 show additional embodiments of the invention wherein the member employs, for example, a distal threaded section having a triple lead pitch and a proximal head having a tapered single point thread. Upon implantation, the difference in pitch of the distal threaded portion and the head generates a force along the axis that can stretch the intermediate portion shown here without threads and has a cutting feature that allows the length of the screw body to be changed under axial force. In some embodiments, it may be desirable to leave the central deformable portion 2002 unthreaded so that a portion of the screw can pass through the bone without applying friction to that portion, which may facilitate the application of a compressive load between the distal threaded portion and the head of the member.

Fig. 21 and 22 show the same device 2110 in an extended and relaxed state. Fig. 23 and 24 show the same device 2120 in a stretched and relaxed state. Device 2110 employs struts having a width 2101 that are thicker than struts of device 2120 having a width 2300. For a given force, this difference may result in different deformations of deformable portion 2002. For example, device 2110 shown in fig. 21 may be extended by a distance of 2200 with respect to length 2100, but device 2120 shown in fig. 23 may be extended by a distance of 2400 with respect to length 2300 for the same load. The length change from length 2300 to 2400 is greater than the length change from length 2100 to 2200. Many variables are involved in the cut characteristics that may affect the axial tension, bending stiffness and torsional stiffness of the structure. The cutting features may be arranged in an infinite number of unit designs, such as diamonds, waves, non-uniformities, sinusoids, slots, ovals or circles. Illustrative examples of some of these embodiments can also be seen in fig. 83, 84, 87, 88, 90, 91, and 92, as well as in other figures.

These patterns may repeat or vary lengthwise, and may combine multiple shapes and sizes lengthwise or around a circumference in the same configuration or deformable portion or portions of the inventive device. The size of the struts may vary along the length of a particular strut and the length of the corresponding deformable portion. The cross-section of the member may also have an infinite number of cell design arrangements, such as those that have been demonstrated, including but not limited to circular, square, oval, symmetrical and asymmetrical. The features and dimensions may vary across the wall or material thickness as well as the cross-section.

Increasing strut length can increase the amount of deflection for a given load condition. This may be advantageous because the overall change in overall structure may be increased, and thus the change in length may accommodate larger bone tissue changes over time. The amount of force applied as compression can then be reduced, which can be a desired characteristic, depending on the desired load distribution.

The radius of the end slots may affect the strain of the struts and increase or decrease the amount of recoverable deformation. The width of the slot may facilitate more or less configuration flexibility. This width also affects the manufacturing process, making wider slots (e.g., machine milling) or narrow slot laser cutting possible.

The outer diameter of the member can affect the overall stiffness and axial tension of the construction by increasing or decreasing the amount of structural material involved and changing the bending moment. The inner diameter of the member may affect the overall stiffness and axial tension of the construction by increasing or decreasing the amount of structural material involved, and may also affect the manufacturing process used to manufacture the construction. The inner diameter may also affect the assembly components or other features used to facilitate the application method of the embodiments.

The number of slots along the radius of the member may affect the axial tension generated by the member, and/or the flexural stiffness of the construction. More shorter length grooves or less grooves of shorter length or grooves distributed unevenly around the radius may promote the desired behavior of the construction. The shape of the slot may affect the axial tension, bending stiffness, torsional stiffness of the structure by affecting local deformation of the structure under load. The angles of the cuts relative to the axis of the member and to the radius of the construct may promote different bending behaviors.

The number of grooves along the axial length of the member, the density of the grooves, the pattern of the grooves, the location of the grooves along the length, and the total length of the area covered by the grooves may also affect the desired performance of the embodiment. By having nested or layered components, multiple components can be used to facilitate desired design intent, with flexible and inflexible layers together forming axially flexible and flexurally rigid configurations. This embodiment may be formed of a unitary member, or may be composed of several different members, and joined together in a rigid fashion or in a manner that leaves degrees of freedom between the bodies. The length of these individual members can affect the performance of the member by increasing or decreasing the required behavior. Axially, the position of the outer or inner layered members may also be used to control the behavior of the embodiment.

Materials may also be used as variables; elastic, rigid, absorbable, biocompatible materials, and any other material may be used alone or in combination with other materials to create the desired set of functions. Surface treatment of the material can also have an effect on the behavior of the structure. The ratios and/or relationships of these variables to one another can be varied by one skilled in the art in light of the spirit of the present disclosure, and all combinations are considered to be encompassed by the present disclosure for the sake of brevity. The exemplary examples described in further detail herein are brief exemplary examples, and the variables in any one figure may be used with all other examples, whether examples, described in the text, or known to those of skill in the art.

Fig. 25-28 illustrate another embodiment of the invention in which distal and proximal portions of device 2800 incorporate features that assist in applying longitudinal or tensile forces to device 2800. Fig. 26 depicts the central axial member 2600 with an engagement feature depicted as threads 2601. Threads 2601 engage with complementary features, such as threads 2701 formed on the interior of device 2800, as shown in fig. 25, 27, and 28. Axial force may be applied to member 2800 by engagement of threads 2601 of central axial member 2600 with threads 2701 within device 2800.

The mechanism allows axial force to be applied in compression or tension, and this may be done after insertion of the screw into the bone, or only after insertion of the distal tip, or before insertion of the screw. It may be desirable to preload the screw implant with compressive or tensile stress prior to insertion into the bone tissue. It will then be necessary to maintain this pre-tension throughout the implantation process. There are many ways to achieve and maintain the loaded or stretched state, but this is just one possible embodiment.

Fig. 29, 30 and 31 illustrate another embodiment of the invention in which the distal end of member 2902 is internally threaded, such as described above with respect to the embodiment shown in fig. 25-28. In this embodiment, to apply an axial force, the head 3004 of the screw member 2902 is captured or retained. This illustrative method of retaining head 3004 of screw 2902 is only one possible solution. The collet 2901 is assembled on the head 3004, with the inner surfaces of the fingers of the collet 2901 formed to fit the outer profile of the head 3004. The compression sleeve 2900 is axially advanced over the collet 2901 to capture the head 3004 within the fingers of the collet 2901, as shown in fig. 30. The screw 2902 is rotated about an axis by a drive mechanism 3002 that passes through the collet 2901 and engages an engagement portion of the head 3004, such as the drive engagement feature 1700 described with respect to the embodiment shown in fig. 16.

An axial force is applied to the screw member 2902 by applying an opposing force to the threaded central member 2903, pressing the axial force against the collet member 3001 and/or the driver member 3002. These three components may cooperate to apply a tensile elongation force or a compressive contraction force along the length of the screw 2902 depending on when the axial load condition is applied during insertion of the device into the bone. The collet 2901 and/or the drive mechanism 3002 may control rotation of the screw head about the axis. Threaded central member 2903 may also be configured to control rotation of screw 2903 about the axis of screw 2902. The collet 2901 may alternatively allow the screw to rotate within the collet 2901 while applying an axial force. Drive member 3002 is an optional member shown here by way of example.

Threaded central member 2903 may be introduced into the screw before, during, or after screw 2902 is inserted into the bone. The length of each compression sleeve 2900, threaded central member 2903, collet 2901, and drive mechanism 3002 is such that control of member 2902 is desired for a given process, possibly coupled with a mechanism that allows and applies the desired forces in the proper sequence. The component 2902 is similar to that previously shown, but any given embodiment or combination disclosed herein may be used with the mechanism to achieve the desired results.

Fig. 32, 33 and 34 illustrate another embodiment of the invention in which the distal end of connecting member 3200 is internally threaded, such as described above with respect to the embodiment illustrated in fig. 25-28. This embodiment illustrates another way in which axial and rotational loads are applied to the connecting member or screw body along and about its axis. In addition to or in lieu of any other engagement feature, driver component 3201 employs threads 3204. Threads 3204 engage threads 3206 on head 3208 of screw 3200. Driver member 3201 and central threaded member 3210 may then exert an axial force in compression or tension along the length of member 3200.

Alternatively, the inner surface of the distal end of member 3200 may be reduced in diameter or reduced in diameter, and the outer surface of central threaded member 3210 may have a corresponding increased or enlarged diameter. The stepped feature interferes such that central threaded member 3210 does not axially extend beyond the stepped feature in screw 3200. This combination will allow axial tension to be applied between the screwdriver and the tip of the screw through the central member along the length of the screw over the length of the screwdriver. The same effect can be achieved by non-rotatably engaging the threads on the screw and the central member, thereby allowing the application of a unidirectional axial load.

Fig. 35 and 36 illustrate another embodiment of the invention in which the distal end of the connecting member 3500 is internally threaded. Such as described above with respect to the embodiment shown in fig. 25-28, and the collet mechanism as described with respect to the embodiment shown in fig. 29-31, in further combination with the threaded driver feature described with respect to the embodiment shown in fig. 32-34; as an illustrative example of combining any and all features disclosed herein.

Fig. 37-39 illustrate another embodiment of the invention in which device 3700 employs a deformable portion similar to deformable portion 2002 without the threads described with respect to the embodiment illustrated in fig. 21-24. The deformable portion 3702 employs a nicked feature 3704. Fig. 38 shows such a nicking feature 3704 of a deformable portion 3702 of device 3700 in a stretched or tensioned state, and fig. 39 shows such a nicking feature 3704 of the deformable portion 3702 of device 3700 in fig. 38 and in an untensioned state. Conversely, if the initial state of member 3700 is closed as the initial state of the expanded state, the reduced state requiring axial force to achieve the compressed state shown in fig. 39, the strained and relaxed states of member 3700 may be reversed. The above-described alternative configurations may be, and do apply to, all embodiments disclosed herein.

The amount of change in length of member 3700 is a result or function of the change in dimension (e.g., width) of undercut feature 3704. This is also a function of the number of nicked features 3704 employed along the length or longitudinal axis of member 3700. The configuration of the orthopedic bone screw can vary the width of each groove using many common materials, including but not limited to titanium, stainless steel, cobalt chrome, SMA (shape memory alloy), nickel titanium alloy, magnesium, plastic, PEEK, PLLA, PLGA, PGA, and other alloys. The amount of change required may range from 0 mm to over 10 mm depending on the application of the mechanism and the application of the program.

Fig. 40, 41 and 42 illustrate another embodiment of the invention in which an apparatus 4000 employs a deformable portion similar to deformable portion 2002 described with respect to the embodiment illustrated in fig. 21-24. In some applications, it may be desirable to apply an axial force to the device or screw 4000 and hold the load until such time as it is desired to release the load. The present embodiment is merely one example of a mechanism that would facilitate such an application. The member or screw body 4000 employs a receiving feature 4002, depicted as a hole or bore in fig. 40 and 42, axially positioned in the distal and proximal portions of the member 4000. The receiving feature 4002 is designed to receive a complementary feature or pin 4106 positioned through the aperture 4104 of the central member 4100.

During the time that the screw is in a loaded or tensioned state, the feature 4106 is inserted into the hole 4104 of the central member 4100 and receives the feature 4002 of the screw 4000. In certain embodiments, the features 4106 are made of biocompatible materials, but have the material properties required to maintain the loaded or tensioned state of the screw. The materials include, but are not limited to, all materials from which the screw and central member may be constructed, and in certain embodiments, are formed from any bioabsorbable material or any other material concept listed herein. In operation, driver 4008 applies an axial rotational force to expand screw 4000 into bone, and central member 4100 is assembled within screw 4000. The central member can then be removed from the screw 4000 by applying an additional force, either axially or rotationally. This force will shear off the member 4106 in the receiving feature 4002 of the screw member 4000. The central member can then be removed as desired.

Alternatively, in embodiments in which the pins 4106 are formed of a bioabsorbable material, the screw member 4000 may be implanted in a stretched state and, after a prescribed amount of time has passed after implantation, the pins are resorbed by the body and exert an axial compressive force between the bone or bone fragments to promote healing and/or fusion.

Fig. 43 and 44 illustrate another embodiment of the invention in which a screw member 4300 employs a member 4302 to provide the ability to resist radial bending or bending of the screw member 4300 relative to axis a-a. The member 4302 may be, for example, a sleeve or tube applied over the outer diameter of the deformable portion 4304 employing the slot 4308. The sleeve 4302 may be free floating or attached to the screw 4300 to allow the length of the screw member relative to the sleeve member 4300 to still change. For example, the sleeve 4302 may be attached to the screw 4300 at one point or end. The sleeve member 4302 may be applied and then welded or bonded to itself to form a continuous circumferential member around a portion of the screw member 4300. Alternatively, the sleeve member 4302 may be threaded onto a screw and then reside in an unthreaded area. The sleeve member 4302 may be made of the same material as the screw or any other material described herein. The sleeve member 4302 may further employ features that help maintain the preload of the screw member 4300.

Fig. 45 and 46 illustrate another embodiment of the invention in which a screw member 4500 employs a filler member 4502, the filler member 4502 partially occupying a space or void 4510 formed by the slot 4508, thereby limiting the ability of the screw member 4500 to change or reduce in length. In addition to occupying the space or void formed by slot 4508, member 4502 may cover an outer surface 4504 of screw member 4500 and/or fill all or a portion of an interior 4606 of screw member 4500.

The filler member 4502 is formed of a material that changes physical and/or chemical properties upon insertion into or exposure to host tissue. In certain embodiments, the filler member 4502 is formed of a dissolvable, bioabsorbable, resorbable, amorphous, degradable, soluble, flexible, meltable, and/or decomposable material. In certain embodiments, filler member 4502 is formed from a material that changes properties such that it becomes or transforms to a state of insufficient strength to resist the compressive forces exerted on the opposing struts that define the space or void 4510 formed by slot 4508. Alternatively, the filler member 4502 is formed of a material having material properties that change such that it is no longer present in the space or void 4510 formed by the slots 4508.

The rate at which the material forming the filler member 4502 allows the struts to move and apply the compressive force can be controlled by material selection and/or adjustment of the material formulation. Depending on the application, it may be desirable to apply the compressive force immediately after implantation or immediately thereafter. Materials that may promote this effect may resemble sugars, salts or other biocompatible soluble materials. The required rate of force application may last weeks or months, where absorbable materials may promote such behavior, such as polylactic-glycolic acid (PLGA); polyglycolic acid (PGA); polylactic acid (PLA); polycaprolactone (PCL) and various copolymers that can be formed by combining them. Materials such as collagen, hydroxyapatite, calcium phosphate, polyvinyl chloride, polyamides, silicones, polyurethanes, and hydrogels may be used as they may also be formulated to change material properties over time. There are many methods known to those skilled in the art for the absorption and decomposition of materials, which are conceptually incorporated herein.

In certain embodiments, the material forming the filler member 4502 is a flexible material that can only be compressed to a known dimension, but can be stretched or elongated. This embodiment can be used to help impart radial bending stiffness, but does not limit the extension characteristics of the expandable member.

In general, this embodiment uses, in addition to the material or materials forming the connecting member or screw, other materials that have sufficient rigidity in one state to hold the struts of the slots of the deformable portion of the device in one position when inserted into tissue, and then, after such insertion, the additional material has a second state in which it modifies the properties to give the struts or slots a force that overcomes the force of the additional material, with a speed of adjustment ranging from no more than a minute to several months.

Fig. 47-49 illustrate additional embodiments of the invention in which a connecting member or screw 4800 employs an inner member 4802 insertable within a lumen 4806 of screw 4800 to increase the radial stiffness of member or screw 4800. Internal member 4802 can be located within the entire length of implant member 4800 or less than a portion of the entire length of member 4800. The internal member 4802 is added or inserted into the screw member 4800 before, during, or after implantation in the body. Inner member 4802 can be solid or hollow. Fig. 47 depicts a solid member 4802 having a threaded head 4804 with a tool engagement feature 4814. As shown in fig. 48, during assembly, member 4802 is inserted into lumen 4806 of member 4800 and extends a length that exceeds the length of deformable portion 4808 of screw 4800. The threaded head 4804 of the inner member 4802 is rotated to engage a receiving feature 4810 formed within the head 4812 of the screw 4800. To join the internal member 4802 and screw 4800 together or with a mechanical interlock feature, the mechanical interlock feature is shown by way of example only.

The embodiment shown in fig. 49 is similar to the embodiments described above and shown in fig. 47 and 48, and employs an interference feature 4902 within the lumen 4806, which interference feature 4902 interferes or resists the inner member 4802 as the threaded head 4804 of the inner member 4802 is inserted into and engages a receiving feature 4810 formed in the head 4812 of the screw 4800, thereby causing the deformable portion 4808 to be stretched or preloaded. The interference feature 4902 may take the form of a reduced diameter or stepped diameter that resists further insertion of the inner member 4802 without expansion of the deformable portion 4808 of the screw 4800. Screw 4800 can then be deployed into the bone with inner member 4802 pre-inserted, and thus screw 4800 pre-loaded.

Upon delivery of the screw 4800, the inner member 4802 can be removed, which will release the preload and allow the expandable segment 4808 to apply an active compressive load to the tissue through the distal and proximal externally threaded members. This activation can be accomplished without completely removing the internal member 4802. The length of inner member 4802 and the depth of head threads 4804 can be designed so that inner member 4802 can be unscrewed the desired shortening distance of the expandable section without removal from the head of screw 4800. This condition allows the inner member 4802 to be held to provide radial stiffness, for example. The inner member 4802 can be hollow or solid to better facilitate procedural implantation over a lead. As described above, assembly by K-wire may be performed using a one-piece hollow driver or a nested two-piece hollow driver.

The inner member 4802 can be made of a material that is dissolvable over time as previously described.

The interference feature 4902 may also be shaped to engage with a driver feature to help facilitate delivery by helping to distribute or carry torque loads to the distal end of the screw and/or to axial loads or tension of the screw. The cross-section of the driver feature can be any cross-section that facilitates load transfer, such as, but not limited to; hexagonal, star-shaped, philips-shaped, slotted, or otherwise.

The embodiment of the connecting member or screw 5000 shown in fig. 50 employs a hollow member 5002 positioned within a lumen 5004 of the member 5000. The hollow member 5002 extends distally a length that exceeds the length of the deformable portion 5006. The hollow member 5002 is located in a surface recess or mating feature 5008, the surface recess or mating feature 5008 having a diameter greater than the diameter of the lumen 5004 of the screw 5000. The difference in diameter may be equal to or equal to the thickness of the sidewall of cannulated member 5002, such that the presence of cannulated member 5002 is not effective in reducing the diameter of lumen 5004. In certain embodiments, the mating features 5008 are machined in the lumen 5004. The length of the hollow member 5002 is slightly shorter than the length of the mating feature 5008 to allow for axial length variations in the screw body. The mating feature 5008 can be inserted into the lumen 5004 in a number of different ways, including but not limited to: a cut tube configuration is employed that collapses and then expands within the lumen 5004; and a cut tube configuration that expands within the lumen 5004 and subsequently expands. A threaded tubular configuration is employed that is transferred into the threads of the mating feature 5008; a multi-part screw 5000 connected around the components; and all other methods of construction described herein.

Fig. 51-54 show additional embodiments of the invention in which member 5100 employs a feature set that allows distal threaded portion 5102 to rotate independently or independently of proximal head 5304. The screw member 5100 employs a tool engagement feature 5106 for inserting the distal threaded portion 5102 into the bone, one of the plurality of deflecting members 5108 and a head retaining feature 5110. The proximal head 5304 employs a tool engagement feature 5412 and a receiving feature 5414. The receiving features 5414 of the proximal head 5304 are configured to receive the head retaining features 5110 of the screw member 5100 to longitudinally and radially couple the distal threaded portion 5102 to the proximal head 5304. While allowing rotational freedom between the distal threaded portion 5102 and the proximal head 5304, such as by a lip and groove arrangement.

Loading of the device 5100 may be accomplished by sequentially rotating the distal threaded portion 5102 and the proximal head 5304 at different or the same rates; the distal threaded portion 5102 and the proximal head 5304 are simultaneously rotated at different or the same speeds. After implantation, by further rotating the distal threaded portion 5102 or the proximal head 5304, the other portion remains stationary. Or by rotating distal threaded portion 5102 and proximal head 5304 in opposite directions. A nested driver set or independent drivers may be used to independently engage the tool engagement features 5106 of the screw member 5100 and the tool engagement features 5412 of the proximal head 5304.

The proximal head 5304 is shown with threads in fig. 53 and 54, but need not include threads. Assembly or attachment of the distal threaded portion 5102 to the proximal head 5304 may be facilitated by radial, inward deflection of the one or more deflecting members 5108. Thereby allowing the receiving features 5414 of the proximal head 5304 and the head retaining features 5110 of the distal threaded portion 5102 to engage.

For clarity, the screw 5100 shown in fig. 51-54 is shown employing a sleeve member such as described with respect to the sleeve member 5002 shown in fig. 50. However, screw 5100 may, but need not, employ such hollow members, and is shown employing only such examples as various combinations of the inventive features contemplated.

One example of a program implementation: distal end 5102 is driven, which can elongate central portion 5100, the body rotates relative to proximal end 5304 but is connected. As the proximal end 5300 rotates and remains stationary, the first driver may engage the distal member 5100 using the features 5106 and elongate the center when the distal threads 5102 engage the bone. The proximal end 5304 and the first driver may be engaged by the cannulated second driver to effectively drive the distal and proximal ends the same distance into the bone while maintaining the preload and active compression.

Alternatively, the entire screw body may be driven into the bone at one time, and then the distal end 5102 may be driven further independently, effectively lengthening the expandable section and creating an axial load.

55-59 illustrate another embodiment of the invention in which the axial force of the engagement member 5600 can be derived from or assisted by the use of a central member 5502. As shown in fig. 55, 57, and 58, the central member 5502 has a distal engagement feature 5504 (e.g., threads) and a proximal head 5506. As shown in FIGS. 57-59, the attachment member or screw 5600 has a distal portion 5608, a proximal head 5610, a deformable portion 5612 therebetween, and a lumen 5722. Although the proximal head 5610 of the screw 5600 is shown as threaded, the proximal head 5610 need not be threaded.

The distal portion 5608 has an internal engagement feature 5714 that is complementary to the distal engagement feature 5504 of the central member 5502, and the proximal head 5610 has an internal engagement feature 5716 that is complementary to the exterior of the proximal head 5506 of the central member 5502. The connection member or screw 5600 has a first state having a length 5618, as shown in fig. 56 and 57, with the deformable portion 5612 in an elongated or expanded state. The connecting member or screw 5600 has a second state of length 5920, as shown in fig. 58 and 59, with the deformable portion 5612 in a shortened or compressed state.

In one embodiment, the central member 5502 is inserted into the lumen 5722 and (1) the distal engagement feature 5504 of the central member 5502 engages with the internal engagement feature 5714 of the distal portion 5608 of the screw 5600, e.g., the proximal head 5506 of the central member 5502 is rotated (2) into engagement with the internal engagement feature 5716 of the proximal head 5610 of the screw 5600. These engagements may occur before or after the screw 5600 is implanted into bone. These engagements limit distal advancement of the central member 5502 through the lumen 5722 of the screw 5600. Continued rotation or engagement of the central member 5502 relative to the screw 5600 exerts an axial tensile force on the central member 5502 while simultaneously exerting an axial compressive force on the screw 5600. Several different results may be achieved depending on the relative modulus of elasticity of the materials forming the central member 5502 and the screw 5600.

For example, if the resilience of the central member 5502 is less than the resilience of the screw 5600, the engagement action will cause the screw 5600 to shorten or compress from the extended state 5618 to the shortened state 5920, as shown in fig. 56 and 59, respectively. If the central member 5502 is more elastic than the screw 5600, the engagement action will result in elongation or stretching of the stretched central member 5502 and thus apply an axial compressive force to the screw 5600. Depending on the design of the screw 5600 and/or the deformable portion 5612 of the screw 5600, the stretched central member 5502 exerts a force on the component, which may then result in a compressive force being applied to the bone that is transmitted through the distal portion 5608 and the proximal head 5610 of the screw 5600. The rate of this change in the length of the screw 5600 will depend on the amount of force exerted by the central member on the assembly. The central member may be constructed, for example, of a material having a high modulus of elasticity such as nitinol, and the screw member may be made, for example, of any suitable material for use in an orthopaedic implant.

In certain alternative embodiments, the proximal head 5506 of the central member 5502 has a thread that is complementary to the thread of the internal engagement feature 5716 of the proximal head 5610 of the screw 5600, similar to the embodiment described above and shown in fig. 47-49. The difference in the pitch of the threaded distal engagement feature 5504 and the threaded proximal head 5506 of the central member 5502 may be such that the proximal head 5506 is advanced faster than the threaded distal engagement feature 5504 through the lumen 5722 of the thread 5600. Thereby, an axial tensile stress along the threaded member 5600 is caused. The loaded state length of the screw 5600 will be similar to or greater than the length 5618 shown in fig. 56. In this embodiment, the screw member 5600 would have an elastically expandable section 5612 as with the other embodiments described herein. Application of the central member 5502 to the depicted configuration will elongate the deformable portion 5612. The construct may be inserted into the bone and the central member 5502 may then be removed, thereby releasing the axial compression of the expandable section.

Fig. 60-63 illustrate additional embodiments of the invention in which the engagement member 6000 is similar to other embodiments presented herein, and further employs additional features 6002 and/or 6204 that function by increasing the effective diameter of the head 6003 of the member 6000 to increase the amount of force required to penetrate or set the head 6003 of the screw member 6000 to the desired tissue or bone. These embodiments enable a greater axial force to be applied to the threaded member 6000, thereby more easily loading the deformable portion 6004 of the threaded member 6000. The member 6002 may be a non-integral or integral enlarged lip, rim or flange associated with the head 6003 of the screw 6000. Feature 6204 is a separate component that is not integral with screw 6000, screw 6000 having a form such as a spring washer that increases the compressive force on the system by applying additional axial tension. The feature 6204 allows the screw member 6000 to rotate independently relative to the feature 6204. The features 6002 and 6204 may be used independently of each other or in combination with each other on any connecting member disclosed herein.

Fig. 64-71 illustrate additional embodiments of the present invention. These features are depicted as being representative and may be employed or otherwise combined with any of the embodiments disclosed herein. The pitch, minor and major diameter variables are adjustable to maximize the compressive force that the screw can generate. The combination of the expandable length and the effective axial tension function can improve the clinical efficacy of bone fusion. Fig. 64 illustrates a side view of a bone fixation device 6400 having an expandable or deformable portion in an unexpanded state, a tapered minor diameter 6402 and variable pitch threads 6401. Fig. 65 illustrates a side cross-sectional view of a bone fixation device 6500 having an expandable section 6502 in a non-expanded state, a tapered minor diameter 6501, a variable pitch thread, and a cannula.

Fig. 66 is a side view of a bone fixation device 6600 having an expandable section in a non-expanded state, variable minor and major diameters, and triple lead screw threads. Fig. 67 illustrates a side cross-sectional view of a bone fixation device 6700 having an expandable section 6702 in a non-expanded state, the expandable section 6702 having variable minor and major diameters and a triple pitch thread feature. Fig. 68 shows a perspective view of a bone fixation device 6800 having an expandable section 6802 in a non-expanded state, variable smaller and larger diameters 6801, and triple lead screw threads. Fig. 69 is a perspective view of a bone fixation device having an unthreaded expandable portion 6901 in a non-expanded state, variable minor and major diameters, a distal triple lead pitch thread 6900, and a variable proximal thread feature 6902.

Fig. 70 shows a side cross-sectional view of a bone fixation device having an expandable section 7001 in a non-expanded state, variable major and minor diameters 7002, and a triple lead thread 7000. Fig. 71 shows a side cross-sectional view of a bone fixation device having an unthreaded expandable section 7101 in a non-expanded state, variable smaller and larger diameters, a distal triple lead pitch thread 7100, and a variable proximal thread 7102.

Fig. 72-79 illustrate yet another embodiment of the invention in which a connecting member or screw 7200 employs a helically deformable portion or portion 7202, a preload member 7301, and a delivery and activation mechanism. Fig. 72 shows a screw 7200 employing an expandable section 7202, a distal section 7201 and a threaded head 7203. The implementation of screw 7200 is achieved by using the three main components shown in fig. 73: screw 7200, a helical pretensioning member 7301 with an engagement rod 7302, and a driver 7304 with a receiving part 7303. Fig. 79 shows the components in cross-section in an assembled state.

Fig. 74 depicts a driver 7304 engaged with a helical pretension member 7301 on a central wire member 7401. The preload members 7301 have a strut width that is wider than the helical gap width of the helically deformable portion 7202. Preload member 7301 is then rotated into screw 7200 and the proximal portion is seated within head 7203 of screw 7200. The drive 7304 and the centerline member 7401 may then be removed from the assembly as shown in fig. 75. The screw may then be inserted into the preloaded bone tissue. The central member and driver may be attached to the screw and driven into the bone tissue. The helical member may then be rotated in the opposite direction and removed, allowing the helical portion to compressively load bone tissue.

In alternative embodiments, the threads 7200 and the external threads of the helical expansion member 7202 can be threaded in opposite directions. Thus, when the distal portion 7201 of the screw is inserted into bone tissue, the helical loading member will expand to create a loaded state when the head of the screw is inserted into the tissue.

Fig. 80-87 illustrate additional embodiments of the present invention. The active compression concept and related embodiments may also be applied to other configurations besides screws. For example, rods are commonly used in orthopedic surgery to repair broken bones and fuse joints. This embodiment shows a rod with receiving features that engage cross-axle screws or pins. Alternatively, one or both ends of the construct may be threaded to engage bone tissue, or any of the previously described embodiments may be made to receive a cross-shaft member. In this embodiment, a clamp is used to facilitate the process of implanting these rod members into tissue.

Fig. 80 depicts a device 8000 implanted in a bone 8005. Device 8000 employs an expandable portion 8001, distal engagement members 8004 and 8006, a distal portion 8003, a proximal portion 8002, and proximal engagement members 8007 and 8008. Fig. 80, 81, 83, and 84 illustrate the device 8000 in a contracted state 8101, and fig. 82, 85, and 87 illustrate the device 8000 in an expanded state 8201. Distal engagement members 8004 and 8006 and proximal engagement members 8008 and 8007 may be used in any combination, such as 3 and 4 or 6 and 8, and may be positioned in multiple planes or a single plane. They may be threaded or unthreaded and they may adopt a function of allowing micro-movements. They may be slots or have a mesh structure. They may be anything known to those skilled in the art.

Rather, as shown in fig. 81 and 82, the embodiments may be stand-alone embodiments with different activation mechanisms, as previously described herein.

FIGS. 85-87 illustrate the expanded and contracted states of the device 8000, and one possible method of transitioning the device 8000 from the contracted state to the expanded state through the use of the member 8701 and the stops 8703 and 8702. For example, stop 8703 can be inserted into member 8200, and member 8701 can then be inserted into the lumen of device 8200. Stops 8703 limit the axial advancement of member 8701, and deformable portion 8001 becomes forced or longitudinally expanded with the additional axial advancement force of central expansion member 8701. The stop 8702 is then inserted into the locking member 8701 within the device 8200 and at least temporarily secures the device 8200 in the expanded state 8201. The device 8200 can then be used to treat a fracture or fusion. Once implanted in the desired anatomy using engagement members 8004, 8006, 8007, and/or 8008, or any suitable engagement strategy, stops 8703 and/or 8702 are removed, dissolved, weakened, sheared, or some other suitable action that will allow member 8701 to extend axially distally laterally. Thus, deformable portion 8001 is allowed to retract or fold, and the length of device 8200 decreases immediately or for a prescribed period of time.

Fig. 88-93 illustrate embodiments and configurations of nick patterns employed in expandable or deformable portions or portions of any of the embodiments of the invention disclosed herein. This pattern may be used to cut the tube of material to make all or a portion of the member 8800. Figure 88 depicts a plan or one-dimensional view of the member 8800 having the cut groove pattern 8801. Fig. 89 and 90 are progressive enlargements of a portion of the nick pattern 8801 shown in fig. 88. The spaces or voids 9002 between the posts 9004 are areas where no material is present. It should be understood that fig. 88-90 may similarly illustrate the pattern 8801 wrapped around the tubular member.

Fig. 91 depicts a plan or one-dimensional view of a component 9100 having a pattern of slits 9101. Fig. 92 and 93 are progressive enlargements of a portion of the nick pattern 9101 shown in fig. 91. The spaces or voids 9302 between the posts 9304 are areas where no material is present. It should be understood that fig. 91-93 may similarly illustrate the pattern 8801 wrapped around the tubular member.

In certain embodiments, the member 8800 shown in figures 88-90 and the member 9100 shown in figures 91-93 are the same member and they use the same cutting pattern in the unexpanded state (figures 88-90) and in the expanded state (figures 91-93). In other words, the expansion or lengthening of the cutting pattern 8801 can result in the voids or spaces 9302 of the cutting pattern 9101 having a larger interior void area than the voids or spaces 9302 of the cutting pattern 8801 shown in figures 88-90.

Fig. 94-101 illustrate additional embodiments and configurations of nick patterns employed in expandable or deformable portions or portions of any of the embodiments of the invention disclosed herein. It will be understood that the grooving patterns shown in fig. 94-101 may represent a planar or one-dimensional representation of the grooving pattern used to form the tubular structure or member, or alternatively, may represent a pattern that has been formed into the tubular structure or member. Fig. 94 shows a slot pattern 9400 having oval shaped slots 9402. The elliptical shaped cuts 9402 may produce higher stress relief of the struts 9401 during deformation and facilitate integration of material or tissue ingrowth between the slots. FIG. 95 illustrates a nick pattern 9500 employing larger and smaller than symbol or transverse chevron nicks 9502. The kerfs 9502 may create alternating strut 9501 strain curves during deformation and may contribute to different axial and torsional stiffness curves.

Fig. 96 shows a kerf pattern 9600 using alternating curved kerfs 9602. The curved cut-out slots 9601 produce alternating strut 9602 strain curves during deformation and contribute to different axial and torsional stiffness curves. Fig. 97 shows a kerf pattern 9700 using overlapping alternating curved kerfs 9702. The overlapping alternating curved cutaways 9702 create alternating strut 9701 strain curves during deformation and contribute to different axial and torsional stiffness curves. FIG. 98 shows a slot pattern 9800 of curved slots 9802 that employs repeated interrupted bends. The repeated interrupted flex slits 9802 create alternating strut 9801 strain distributions during deformation and contribute to different axial and torsional stiffness distributions. Figure 99 shows a slot pattern 9900 employing longitudinal "S" or curved slots 9902. The longitudinally curved slots 9902 create alternating strut 9901 strain curves during deformation and contribute to different axial and torsional stiffness curves.

Fig. 100 and 101 illustrate a nick pattern 10000 employing longitudinal or longitudinal "S" or curved symmetrically repeating nicks 10002. The undercut 10002 creates an alternating strut 10001 strain profile during deformation and contributes to different axial and torsional stiffness profiles. The cutback pattern 10000 can be used, for example, to form a helically expanding or deformable portion 10003 of the screw member 10006. The cutaways 10002 of the cutaways pattern 10000 of the deformable portion 10003 can be oriented in a direction opposite the threads 10004 of the member 10006. After insertion of the distal end of the screw 10006 into bone tissue, the helical deformable portion 10003 is loaded when or before the head 10008 of the screw 10006 is inserted into tissue.

Fig. 99, 100 and 101 may also be configured such that the diameter of the expandable 10003 portion may increase or decrease upon loading and unloading of the member. This may be advantageous to increase the interface of the bone tissue as the diameter increases or to help promote a mechanical interlock on the delivery mechanism as the diameter decreases.

FIG. 103 is a depiction of various stress-strain curves for various materials that may be relevant to embodiments of the present invention. Superelastic nickel titanium alloys have constant stress characteristics with substantially flat loading and unloading curves under large strains. Compared to other common materials used to make screws (e.g., titanium alloys or stainless steel alloys), the modulus of superelastic nitinol is very similar to that of bone. Constructing embodiments of the present invention results in an implant that potentially does not stress shield bone. This allows the design of devices that exert constant stress on various shapes. The superelastic material used to form the embodiments may be a Shape Memory Alloy (SMA), superelasticity being a unique property of SMA. The initial increase in deformation strain produces a large stress in the material, which then reaches a stable plateau as the stress continues to be introduced. As the strain decreases, the stress again levels off, providing a substantially constant stress level. This property of the superelastic material allows embodiments of the present invention to be preloaded with a compressive force either before or after insertion into a desired bone segment.

According to one embodiment of the invention, the superelastic materials used to form the embodiments include, but are in no way limited to, shape memory alloys of nickel and titanium, commonly referred to as nitinol or alloys containing more than fifty percent nickel. According to an exemplary embodiment, these embodiments may be formed from a nickel titanium alloy, as nickel titanium alloys may provide low constant forces at body temperatures. Nitinol can be optimized to be in the superelastic austenite phase at body temperature. This is achieved by setting the austenite finish temperature Af below 98.6 degrees fahrenheit. Ideally, this would be done after the screw machining in order to anneal out any residual strain. Further, the elongation reduction of nitinol is about 10%, which is approximately equal to the subsidence rate of the orthopaedic surgeon. However, it will be understood that many materials may be used in the construction of the embodiments disclosed herein.

Fig. 102 and 104 illustrate generally modified screw or connecting member features to maximize fastener efficiency in various applications including, but not limited to, pitch, tip design, cutting features, self-tapping, self-drilling, minor diameter, major diameter, rake angle, finishing, shank length, head size, head angle, cannulation, tapered thread, single point, multiple start, triple thread, variable pitch, variable taper, variable minor diameter and major diameter. In certain embodiments of the invention, any and/or all of these variables are employed to maximize fastener performance. The features of preexisting screws can be used in conjunction with the inventive embodiments disclosed herein to achieve the active compression feature.

Fig. 104 depicts a screw having a triple start thread design. This means that there are three separate "ridges" 10402, 10403 and 10404 wrapped around the cylinder of the screw body. Each time the body of the screw is rotated 360 degrees, it will advance axially a distance equal to the total width of all three ridges 10402, 10403 and 10404. By way of comparison, fig. 105 depicts a single start thread design. FIG. 106 shows a dual start thread design; FIG. 107 shows a triple start thread design. The advantage of using multiple starts is that the amount of travel can be increased for a given rotational movement, which, together with having different starts and/or thread pitches on longitudinally opposite ends or portions of the same screw, can generate axial forces along the length of the screw between different threaded portions.

Fig. 108 illustrates a notch pattern 10800 employing repeating interrupted notches 10801. The slots 10801, 10803, and thus the struts 10802, are non-parallel and non-orthogonal to the longitudinal axis of the engagement member or screw in which the slot pattern 10800 is employed. In other words, the slots 10801, 10803, and thus the struts 10802 of the slot pattern 10800 are inclined relative to the longitudinal axis of the engagement member or screw in which the slot pattern 10800 is employed. By oblique orientation, the cut groove pattern 10800 creates an alternating strut 10802 strain profile during deformation and contributes to different axial and torsional stiffness profiles.

The cuts 10803 are oriented differently within the cut pattern 10800 than the cuts 10801. This creates a non-uniform pattern around the circumference of the deformable portion in which the nick pattern 10800 is employed. This non-uniform pattern around the circumference of the deformable portion creates a non-uniform behavior or stress and strain distribution of the deformable portion about the axis of the pattern of cuts employed. This non-uniform behavior has clinical benefits by allowing more deformation of one plane or direction relative to another. Any combination of patterns may be combined to achieve the desired behavior. Varying the kerf pattern, kerf density, kerf length, kerf shape, and other variables described herein may be combined over and around the entire length of the deformable portion to produce desired mechanical properties.

FIG. 109 illustrates an embodiment of a joining member formed of a non-unitary construction in accordance with the present invention. It will be understood that all of the embodiments disclosed herein may be made from several separate parts or components and then joined together. For example, various separate components that may be used to form the connecting member may include, but are not limited to, a distal threaded portion, a central deformable portion, a proximal head, and an inner or outer radial stiffening member. Advantages of non-unitary construction include, but are not limited to, ease of manufacture, manufacturing costs, optimization and customization of material properties.

Materials that may be used to form any of the individual components include, but are not limited to, titanium alloys, stainless steel, cobalt chrome alloys, polymers such as PEEK, biodegradable materials such as magnesium, PLLA, PLG, and others. Embodiments included herein may be constructed entirely of multiple parts and then combined together in a manufacturing or clinical setting. Methods of joining, coupling or forming a combination of separate components include, for example, snap-fitting, welding, bonding, sintering or other methods known in the art. The separate components may be made of different types of materials or the same type of materials. The multi-segment design may facilitate a simpler and/or more cost-effective manufacturing process. The multi-segment design may provide customized functionality in a clinical setting, allowing a user to combine desired individual components together to build a desired connecting member. FIG. 109 illustrates one example of a union or coupling 10901 of a distal threaded portion 10900 and a deformable or expandable segment 10902.

Fig. 110 and 111 show a pattern of kerfs 11001 that employ radially repeating kerfs 11002. The radially repeating cuts 11002 create a strain profile of the alternating struts 11001 during deformation and contribute to different axial and torsional stiffness profiles. The pattern of cuts 11001 may be used in a connecting member or screw 11000 having a distal threaded portion 11004 and a deformable portion 11006. The deformable portion 11006 has an outer diameter 11008 that is larger than a minor diameter 110010 of the distal threaded portion 11004. The larger diameter of the deformable portion 11006 may allow for the use of a thicker cross-sectional wall whose thickness may be manipulated to adjust the axial tension or axial and/or torsional stiffness of the screw 11000. The screw 11000 may be implanted by preparing a tissue cavity formed with a stepped diameter drill to promote interference between the tissue and the screw being optimized. This embodiment demonstrates features that can be used in any of the embodiments disclosed herein. An anti-rotation or anti-backup feature 11011 may further be employed to facilitate securing the screw into tissue. Feature 11011 is shown here as a cut on the thread that forms an edge that the tissue engages when rotated in a direction that will loosen or remove the screw. The features 11011 may take many forms including, but not limited to, flared tangs, cutting patterns, assembled components, or otherwise. Such anti-rotation or anti-backup features may also be used in any of the embodiments disclosed herein.

Fig. 112 shows a notch pattern 11201 using radially repeating notches 11202. The radially repeating cut 11201 allows the deformable portion 11206 of the connecting member or screw 11200 to bend or deform radially relative to the longitudinal axis 11204. Radial bending or deformation properties may be imparted in any of the embodiments disclosed herein. Such radial deformation may or may not be fully elastic in nature, i.e., a coupling member employing such radial deformation characteristics may or may not return to an original shape that is symmetrical about axis 11204. This feature allows the connecting member or screw 11200 to tighten or engage tissue along a non-linear path. This property may be useful in environments where repeated bending is required, as the strain level may be designed to have a longer fatigue life than a solid screw that is subjected to the same amount of deformation. The bending force of the member can be tailored to achieve the desired clinical treatment by varying all of the previously described features.

In another embodiment, the connecting member or screw is inserted in a straight or axial manner, and the rest state of the screw may be off-axis or curved. The bending force of the screw can then be used as a desired therapy to move the bone fragments after implantation. The screws or connecting members may be formed in a curved, bent or helical shape and mounted or delivered in a straight shape to achieve the desired clinical treatment.

Fig. 113 is a flow chart depicting one possible method and procedural progression for inserting a connection member of the present invention into bone tissue to facilitate a desired treatment. Expansion begins by inserting a K-wire or guide pin into the desired placement location, e.g., a fracture plane across the bone. Once the lead is placed, a measurement of the desired length of the connecting member can be made using the relative length of the lead and the bone surface. The connecting member of the invention can then be inserted into the bone above the K-wire, for example by rotation. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, the additional friction created by the increased size of the head, as well as the different spacing and/or origin of the head relative to the distal portion of the connecting member, will apply a compressive force to the bone segments throughout the fracture plane. The force will also exert the axial tension characteristics of the engagement member, effectively elongating the engagement member and storing potential energy in the axial tension. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing.

Fig. 114 is a flow chart depicting one possible method and procedural progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. Expansion begins by inserting a K-wire or guide pin into the desired placement location, e.g., a fracture plane across the bone. Once the lead is placed, a measurement of the desired length of the connecting member can be made using the relative length of the lead and the bone surface. Thereafter, a hollow drill bit is inserted over the K-wire to increase the diameter of the hole and potentially promote a better mechanical fit between the bone and the connecting member. The connecting member may then be rotated into the bone through the K-wire. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, additional friction due to the increased size of the head and the different pitch and/or origin of the head relative to the distal portion of the connecting member will apply a compressive force to the bone segments of the entire fracture plane. This force will also be applied to the axial tension characteristics of the screw, effectively lengthening the connecting member and storing potential energy in the axial tension. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing.

Fig. 115 is a flow chart depicting one possible method and procedural progression for inserting the connection member of the present invention into bone tissue to facilitate a desired treatment. The procedure begins with the insertion of a drill bit into a desired placement location, such as a fracture plane across a bone. Once drilled, the desired length of the connecting member is measured using a depth gauge and the bone surface. The connecting member may then be rotated into the bone. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component is engaged with the bone, the additional friction caused by the increased size of the head and the different pitch and/or pull-off of the head relative to the distal threaded portion of the connecting member will apply a compressive force to the bone segments of the entire fracture plane. The force will also be applied to the axial tension characteristics of the connecting member, effectively elongating it and storing potential energy into the axial tension. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing.

Fig. 116 is a flow chart depicting one possible method and procedural progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. The process begins by preloading the connecting member onto the delivery mechanism. The preload force is an axial tension characteristic that axially stretches the connecting member of the present invention and is maintained during insertion of the connecting member into the bone. This preloading may be done at the manufacturing facility or in the clinical environment of the end user. The next step is to insert the drill bit into the desired placement location, such as a fracture plane across the bone. Once drilled, the desired length of the connecting member can be measured using a gauge and bone surface. The connecting member may then be rotated into the bone. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. Once the screw member is implanted into the bone, a mechanism is activated that releases the preloaded axial tension. The connecting member will apply a compressive force to the bone segments at the fracture plane. After releasing the stored energy, the stored axial tension energy will continue to exert force on the bone across the fracture plane, creating the desired therapeutically beneficial pressure to aid healing.

Fig. 117 is a flow chart depicting one possible method and procedural progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. Expansion begins by inserting a K-wire or guide pin into a desired placement location, such as a fracture plane across a bone. Once the lead is placed, the relative lengths of the lead and the bone surface can be used to measure the desired length of the connecting member. The connecting member may then be inserted into the bone above the K-wire, for example by rotation. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, additional friction due to the increased size of the head and the different pitch and/or origin of the head relative to the distal portion of the connecting member will apply a compressive force to the bone segments of the entire fracture plane. At this point, the distal portion of the connecting member may be driven further forward while the proximal head remains stationary, which will generate further force on the fracture plane. The force will also be applied to the axial tension characteristics of the connecting member, effectively elongating it and storing potential energy into the axial tension. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing.

Fig. 118 is a flow chart depicting one possible method and procedural progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. The procedure begins with the insertion of a drill bit into a desired placement location, such as a fracture plane across a bone. The desired length of the connecting member is measured using the depth gauge and the bone surface. The connecting member may then be inserted into the bone, for example by rotation. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, additional friction due to the increased size of the head and the different pitch and/or origin of the head relative to the distal portion of the connecting member will apply a compressive force to the bone segments of the entire fracture plane. At this point, a tensioning member may be applied to the connecting member, which will create further force on the fracture surface. The tensioning member may be a separate member that is assembled into the connecting member to provide additional axial tension to the assembly. The force will also be applied to the axial tension characteristics of the connecting member, effectively elongating it and storing potential energy into the axial tension. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing. The additional axial tension members may also provide additional resistance to bending of the assembly.

Fig. 119 is a flow chart depicting one possible method and procedural progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. The process starts with the preloading of the connection members. The preload force is an axial tension of the axial tension characteristic of the connecting member of the present invention and is maintained during insertion of the connecting member into the bone. Such pre-tension may be achieved in the clinical environment of the manufacturing plant or end user. The process continues with the drill inserted at the desired placement location (e.g., a fracture plane across the bone). The depth gauge and bone surface may be used to measure the desired length of the connecting member. The connecting member may then be rotated into the bone, for example. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, additional friction due to the increased size of the head and the different pitch and/or origin of the head relative to the distal portion of the connecting member will apply a compressive force to the bone segments of the entire fracture plane. At this point, the preload member can be removed from the connecting member, which will create further force on the fracture surface. The preload member may be a separate member assembled into the engagement member. After insertion is complete, the stored axial tension energy will continue to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure to aid healing.

FIG. 120 is a flow chart depicting one possible method and manufacturing process for constructing a joining member in accordance with the present invention. From a metal ingot such as a nickel ingot having a suitable chemical structure, e.g., 55.8% nickel, 44.185% titanium, 0.01% oxygen and 0.005% carbon, the ingot transition temperature is less than 5 degrees celsius, the tube is drawn to the appropriate inner and outer diameters, wall thickness, and desired physical properties, e.g., tensile strength of about 145,000PSI and elongation in excess of 10%. It will be appreciated that the above values are reference values, and that the actual values may vary depending on the desired characteristics of the final configuration. The next step is to machine the desired external profile of the threads and features into the tubular. The machining may be standard machining techniques, low temperature machining, EDM (electrical discharge machining), grinding or other techniques known to those skilled in the art.

After the desired profile is obtained, axial tension features are added to the construction. These features are obtained by removing the desired material using methods well known to those skilled in the art (e.g., laser cutting, EDM, chemical etching, and water jet machining). Once all of the features are formed in the construction, the part may then be heat set or annealed. The purpose of heat-setting may be to relieve any residual stresses in the part during any of the preceding processing steps. Additional physical or dimensional changes may be imparted to the structure by the heat treatment step. The heat setting may be an adjustment or regulation of the austenite transformation temperature.

The last step is the surface finish of the part. This can be accomplished by subjecting the heavy oxide surface of the part to a series of chemical or mechanical etches. Once the surface is relatively uniform, an electropolishing process is used to smooth the surface and build up a layer of approximately 200 angstroms of titanium oxide. These two process steps also serve to further eliminate any heat affected zone on the part due to any machining or cutting process. These steps also improve the biocompatibility, corrosion resistance and fatigue life of the structure. The part may then be subjected to a final cleaning process and then packaged. Sterilization of the screw may be performed by the manufacturer or at the clinical site.

FIG. 121 is a flow chart depicting one possible method and manufacturing process for constructing a joining member in accordance with the present invention. The method is similar to the process described with respect to fig. 120, except that the early step of drawing into the tube would be replaced by drawing into a solid rod. Starting with a solid rod, the structure then needs to be cannulated. Such cannulas are created by machining, gun drilling, EDM or other methods known to those skilled in the art.

FIG. 122 is a flow chart depicting one possible method and manufacturing process for constructing a joining member in accordance with the present invention. The method is similar to the process described with respect to fig. 120, except that the undercut that ultimately forms the deformable portion of the member to form the axial tension feature is formed prior to machining the external or threaded features (e.g., distal and proximal threads).

The connecting member and/or the screw according to the present invention may also be processed in an elongated state and then formed in a shortened state in a heat setting step. This technique facilitates easier manufacturing of the cut-out feature and electropolishing steps. In addition to the methods described herein, the multipart constructs can have all of these included variants, as well as more. The method described in fig. 120-122 is centered on the nitinol material. However, the method for other materials (e.g., other titanium alloys and/or stainless steel alloys) would be similar. The final step when using other materials may include the addition of surface coatings such as anodization or plating and/or passivation. In addition, alternative manufacturing methods also include deposition, molding, casting, sintering, and other methods known to those skilled in the art are also included as potential manufacturing techniques in the present invention.

For clarity only, the methods described and illustrated with respect to fig. 113-122 are described as being performed in a progression or order of different steps. It is to be understood and within the scope of this disclosure that such steps are performed in an alternating order or sequence and that the embodiments may omit steps shown and/or described in connection with the illustrative methods. Embodiments may include steps not shown or described in connection with the illustrative methods. Illustrative method steps may be combined. For example, one illustrative method may include the steps shown in conjunction with another illustrative method.

Fig. 123-125 depict additional embodiments of engagement members that may be used in conjunction with those previously disclosed and engagement members. Fig. 125 illustrates a deformable or expandable section 12300 of an engagement member 12500, which employs a plurality of different portions 1251, 12502 and 12503. Portions 1251, 12502 and 12503 have different axial and bending spring characteristics due to the difference in geometry of the notch feature along the longitudinal axis of deformable portion 12300. Having the ability of one, two, three, or more different portions to produce different behavior is beneficial to the clinical advantages of the deformable portion 12300, for example, evenly or unevenly distributing radial bending or flexural loads over a given length, facilitating radial bending around a defined length of the member, and being readily resistant to torsional loads upon insertion. In some embodiments of the invention, the pattern of kerfs may be asymmetric about the circumference of the central deformable portion. For example, the pattern of kerfs may take on different sizes around the circumference of the central deformable portion to create asymmetric mechanical properties.

Portions 12501, 12502, and 12503 may employ different axial stiffnesses while maintaining the same radial bending stiffness, allow preferential bending in one or more defined planes, allow the same radial bending stiffness and different axial stiffnesses, or allow adjustment of any and all of the design parameters disclosed herein to produce desired results. As shown in fig. 123, parameters that may be changed include, but are not limited to: dim a vertex or node size or width 12301; dim a vertex or node size or width 12301. Dim B pillar width 12302; dim C window or kerf width 12303, end of kerf width multiplied by vertex or node radius 12310; the length 12304 of the Dim D struts, and the thickness of the struts or the wall thickness of the material of the members. These variables work together to produce the desired property, which may vary according to the clinical indication.

One embodiment may employ an exemplary algorithm of the following ratios and relationships; dim a 12301 is not less than 1.5 times Dim b 12302; dim B12302 is within 50% of the strut width; dim 12310, of sufficient magnitude to remain below 15% strain during deformation, then the value of Dim C12303 is determined; the overall diameter of the plurality of struts and members over the circumference about the longitudinal axis will determine the Dim D length of the strut 12304, which will have a profound effect on the amount of deflection of the embodiment. Thus, for a connection member having a diameter of 3.5mm at its distal threaded portion, the dimensions may be in the range of the wall thickness WT: 1 mm; 3 circumferential struts; dim B123020.75 (WT); dim A123011.125 mm; dim D123022.5 mm; dim C123030.006-0.020 inches, depending on torsional and axial stiffness requirements. These numbers can be adjusted to bring up the desired spring effect. As with the one embodiment, another set of identical features may be provided having different dimensions along the length, e.g., Dim E12305, Dim F12306, Dim G12307, and Dim H12308 (shown here as about half the Dim B thickness) may produce different axial spring forces.

Fig. 124 illustrates another embodiment of a slot pattern 12400 that employs slots 12402 having opposing features 12401. The opposing features 12401 help limit axial and torsional movement or deformation of the cut-groove pattern 12400 by interrupting such displacement. If the struts attached to the opposing features 12401 are displaced from one another, the opposing members 12401 contact or interfere with one another, thereby limiting deformation of the cut 12402. It will be understood that the opposing features 12401 may have any shape that will fit into the limited space available and not otherwise impede the function of the stud member.

126-128 illustrate another embodiment of the invention wherein the connecting member 12600 employs a deformable portion 12602 that deforms or expands in both a radial and longitudinal direction. In some embodiments, deformable portion 12602 has an initial relaxed state with an outer diameter greater than the outer diameter of the distal and/or proximal portions, such as shown in fig. 127 or 128. Such expansion may facilitate the ability to apply torque at the distal portion of the engagement member 12600. For example, the driver can be inserted all the way through the lumen of the connecting member 12600, through the proximal head portion 12604 and deformable portion 12602, and into a socket or receiving feature of the distal portion 12608. The distal portion 12608 can then be driven further into the tissue, thereby transforming the connecting member 12600 from either length Dim Ls 12712 (FIG. 127) or Dim Lss 12814 (FIG. 128) to length Dim L12610 (FIG. 126), while reducing the diameter of the deformable portion 12602 and creating an axial tension in the member 12600. The enlarged diameter deformable portion may also improve its retention of the connecting member within the bone tissue, thereby improving the effectiveness of the connecting member.

In another embodiment, deformable portion 12602 may be formed having a reduced initial diameter to provide a desired retention force. These diameters, which may be expanded or reduced, may be facilitated by the geometry of the slots of deformable portion 12602 and by the heat setting of member 12600.

As shown in fig. 126, the member 12600 can have a length Dim L12610, which is the maximum length of the member 12600 when the proximal head portion 12604 and the distal portion 12608 are furthest from each other. As shown in fig. 126, the struts of deformable portion 12602 are primarily parallel to the longitudinal axis of member 12600. When the deformable portion 12602 is allowed or activated to shorten its structure, thereby shortening the member 12600 to a length Dim Ls 12712, as shown in FIG. 127, the undercut of the deformable portion 12602 changes shape and the struts are no longer parallel to the longitudinal axis of the member 12600 and the overall diameter of the deformable portion 12602 increases. The amount by which this diameter increases will depend on the amount of angular displacement of the post 12703 and the length of the post of the deformable portion 12602. As shown in fig. 128, having a length of Dim Lss 12814, the shape of the slot of the deformable portion 12602 is further altered, and the parallelism of the posts to the longitudinal axis of the member 12600 is even lower, and the overall diameter of the deformable portion 12602 is further increased.

The member 12600 can be fabricated to initially assume any of the states shown in fig. 126-128 by a specified heat treatment. The initial or rest configuration may be set to produce a particular amount of force exerted on the length change. The member 126 may remain in tension in the delivery system until the time required to shorten the device is required. Any of the above mechanisms or other means may accomplish the treatment.

Fig. 129-132 illustrate yet another embodiment of the invention wherein the connecting member employs a deformable portion 12900 that deforms or expands in a longitudinal direction. In certain embodiments, the devices and methods of the present invention provide a screw having a central deformable portion with an outer diameter greater than the diameter of the distal portion and capable of applying a torque at the distal portion. A driver is inserted through the proximal portion and the central deformable portion and into a receptacle formed in the interior of the distal portion to assist in twisting of the device. In certain embodiments, deformable portion 12900 has an initial relaxed state with an outer diameter greater than the minor diameter of the distal threaded portion. The body also has features on the distal section inner diameter that can engage and transmit torque and axial loads.

An interference or engagement feature 12901 shaped to engage with an operator feature may also be employed in order to help facilitate delivery by helping to distribute or carry torque loads to the distal portion of the screw and/or axial loads or tension of the screw. The cross-section of the driver feature may be any cross-section that facilitates load transfer, such as, but not limited to; hexagonal, star-shaped, philips-shaped, slotted or otherwise.

Certain embodiments may also employ a proximal engagement feature 12905, shown here as hexalobal, and an inner lumen 12902 that is stepped or changes in diameter one or more times along the length of the axis. The increased proximal inner diameter of lumen 12902 can facilitate a larger diameter engagement driver 13001, allowing for greater torque application. The outer diameter of the expandable or deformable portion 12900 shown here is the same as the major diameter of the distal threads 12904. Here, the diameter of the distal inner lumen portion 12903 is shown to be smaller than the diameter of the proximal inner lumen portion 12907. This configuration is illustrative, and the proximal and distal inner lumen portions may have the same diameter, the outer diameter of the expandable or deformable portion 12900 may also be greater than or less than the outer diameter of the largest diameter of the distal threads 12904.

The inner diameter of the engagement feature 12901 is large enough to allow a K-wire to pass through to aid in the clinical delivery of the screw. The drive member 13001 has a distal drive member 13002, which distal drive member 13002 has an engagement feature shown here as a hex driver. The distal driver member 13002 can articulate in unison with the proximal drive mechanism 13000 and the engagement features 13003 or independently of both axial and rotational movement. The mechanism is capable of transferring axial and torsional loads at both the distal and proximal ends of the screw embodiment. The distal drive member 13001 may also be cannulated to allow passage of a K-wire.

Fig. 133, 134, and 135 depict illustrations of an embodiment of the invention in which a K-wire member 13304 is inserted into bone members 13301 and 13302 along axis 13303. The bone members 13301 and 13302 are not completely reduced and a gap 13306 is left on a portion of the surface of the bone segments 13301 and 13302. Known or standard screw members 13400 may be employed to pull or draw bone members 13301 and 13302 toward one another to provide compressive axial tension or force. Bone members 13301 and 13302 may represent a bone that is to be broken into two pieces or two bones that are to be fused together. The bone may for example be cortical or cancellous bone or both. The standard screws 13400 pull the segments together, but disadvantageously, the axial path 13303 is maintained relative to the bone segments, and the gap 13401 may not be completely reduced.

Rather, the connecting member 13500 according to the present invention is operable to vary the axial length and axial alignment. The dimensional change occurs over all or a portion of the deformable or expandable section 13504 of the member 13500. As shown in fig. 135, elongated or axially displaced member 13500 applies a compressive force to bone members 13301 and 13302, which pulls bone members 13301 and 13302 toward one another. This compressive force combined with the axial flexibility of the inventive device allows the gap 13306 to decrease more completely to a reduced state 13501. This ability to deviate from the original axis 13303, 13503 of entry and the axial and radial flexibility of the member 13500 promotes more complete bone segment apposition, thus facilitating healing of the bone members 13301 and 13302 together and/or formation of a fusion or bond 13501.

In addition to the extreme compressive load created by member 13500, there is also stored energy or force of deformable portion 13504, which may exhibit a continuous load and/or absorb bone material over time. The stored compressive energy or preload advantageously provides a compressive force through the bone elements to assist the healing or fusion process.

Fig. 136 is a graphical representation of some of the differences in load profiles of one embodiment of the connecting member of the present invention and a standard screw. The vertical axis represents the compressive force applied to the bone segments in percent. The horizontal axis represents the change in distance of the bone segments or the penetration of the screw member into the bone tissue. The device of the present invention may exhibit compressive forces on the bone segments or tensile forces on the device over a greater length change than standard screws or currently available compression screws. This figure depicts the difference between a standard screw such as that shown in fig. 102 and an active compression screw such as any of the embodiments disclosed herein.

Fig. 137 and 138 depict another embodiment of the present invention. Fig. 137 and 138 illustrate partial side views of a portion of a cutback pattern of a bone fixation device having an unthreaded, helical deformable segment in an unexpanded state, according to an aspect of the present invention. Fig. 137 and 138 illustrate a slot pattern 13700 that employs a longitudinal spiral wound about a central longitudinal axis to form a portion of a body of a bone fixation device. The slots 13702 create alternating strut 13701 sizes and strain distributions during deformation and contribute to different axial and torsional stiffness distributions.

For example, the notch pattern 13700 can be used to form the deformable portion 10003 of the screw member 10006 (fig. 100 and 101). The slots 13702 of the deformable portion may be oriented in the same or opposite direction as the threads 10004 and 10008 of the member 10006. Following insertion of the distal end of screw 10006 into bone tissue, the helical deformable portion 10003 of the cutback pattern 13700 is employed to create a loaded state upon or prior to insertion of the head 10008 of the screw 10006 into tissue. The helical cutback pattern 13700 acts as a spring member to provide a resilient deflection that can store energy to be applied to the screw engagement features of the distal thread and proximal head features. The kerfs 13702 of the kerfs pattern 13700 may have a constant pitch as shown in fig. 137 and 138, or may have a variable pitch. This embodiment is used as an extension spring in tension. For purposes of description, the struts 13701 of the slot pattern 13700 have leading edges 13704 corresponding to the distal direction 13706 and trailing edges 13705 corresponding to the proximal direction 13707. The drawings may also be interpreted in the opposite direction.

The kerfs pattern 13700 shown in fig. 137 and 138 may also be configured such that the diameter of the deformable portion formed by the kerfs pattern 13700 may be increased or decreased upon loading and unloading of the member. Increasing the bone tissue interface is beneficial when the diameter is enlarged and facilitates a mechanical interlock on the delivery mechanism when the diameter is reduced. The loading of the center portion may increase or decrease the distance between the posts 13701. Spring performance is well known and all variables that affect spring force can be used here to achieve a desired clinical result. Pitch 13703 can be varied to match the desired spring and bending stiffness, and the width of posts 13701 corresponds to pitch 13703.

FIG. 137 is a partial view of a plan representation of a pattern machined onto a tube or curved surface. The flat pattern can be used to program a laser cutter programmed with a two-dimensional machine code. Similarly, fig. 137, 143, 150, 152, 157, 160, 163, 165, 167, 171, and 173 may each represent such a partial plan pattern view. Fig. 138, 139, 154, 158, 161, 168, 170, 172, 174, and 176 show partial views of a tube and/or deformable portion over which a corresponding planar pattern is wrapped. These partial views may show machined tubes with corresponding plan patterns.

Fig. 138 is a partial side view of a bone fixation device having a non-threaded helically expandable section in a non-expanded state in accordance with an aspect of the present invention. The ends not shown here can for example be distal and proximal screw heads.

FIG. 139-149 depicts another embodiment of the invention in which the deformable portion is loaded in multiple directions. First, the deformable portion is subjected to torsional loading as the screw is driven into or removed from the tissue. The load is transferred from the proximal head of the screw member to the distal thread of the screw member through or through the deformable portion. Depending on the direction of the cuts of the grooving pattern and the direction of the applied torsion, the load may have the effect of lengthening or shortening the deformable portion. For example, the length of a wound spring form or shape loaded in the winding direction increases during its loading. Likewise, the diameter may change during loading. In some applications, it may be desirable to minimize the amount of angular deflection from the proximal end to the distal end of the screw member.

In addition, the deformable portion is subject to compression or tension by the forces exerted by the distal and proximal ends of the screw and their interaction with the tissue during insertion and/or removal from the tissue. The axial load may apply a torsional load distally relative to the proximal end. In some applications, it may be desirable to minimize the amount of angular deflection from the proximal end to the distal end of the screw.

Fig. 139-149 illustrate a twist engagement feature along all or a portion of the length of the deformable portion. The twist engagement feature serves multiple functions. When the struts of the deformable portion are wrapped or expanded, the engagement features of one strut engage with the corresponding engagement features of the next or adjacent strut, thereby torsionally limiting the displacement of the respective strut. Torsional loads can be transmitted throughout the length of the structure, thereby limiting the overall rotational displacement with respect to each end. Depending on the design, the torsional engagement feature may contribute to the elongation of the deformable portion or may inhibit such elongation.

Further, the torsional engagement feature can help shorten the deformable portion during expansion, if desired. The torsional engagement feature may be designed to be neutral with respect to the force vector, thus having no benefit with respect to either lengthening or shortening. The angle of the edges of the twist manipulation feature relative to the vector or direction of the applied force may be manipulated to produce a number of different desired behaviors in the deformable portion of the fixation member. For example, the shape may be a shape that: which initially encourages elongation and then resists elongation after a certain length is achieved. The location and shape of the engagement features may be such that an axial bending load is applied to the structure to produce a change in shape of the asset that may be treated.

Fig. 139 is a partial side view of a deformable portion of a bone fixation device employing a torsional engagement feature in a twisted state according to an aspect of the present invention. The twist engagement features 13903 are features that extend into or interlock or interdigitate with adjacent receiving engagement features 13903. The shape, size, number, and location of the notches 13902 that form the engagement features 13903 can vary widely. The cut pattern 13900 takes a path to create a torsional engagement feature 13903, which torsional engagement feature 13903 is attached to or incorporated into or as part of the strut 13901. In the example shown in fig. 139, the helical strut 13901 actually has six turns, and therefore each turn must absorb approximately one-sixth of the total tension or compression. If such a deformation is, for example, about 3mm, each torsional engagement feature should move or shift, for example, about 0.5mm or 0.020 inches. As the number of turns increases, the individual strokes decrease and vice versa. The deformable portion may be deformed at a constant rate or amount along the length. The deformable portions may be deformed at a variable rate or amount along a length having a length that deforms one portion more than the other portion. The illustrative drawings disclosed herein represent the concepts described herein.

Fig. 140-142 illustrate some of the variables of the twist engagement feature of the present invention. The helically wound struts 13901 and 14101 of member 14000 and 14100, respectively, shown in fig. 140 and 141, respectively, are oriented in opposite directions relative to the struts 14201 of member 14200 shown in fig. 142. Helically wound struts 13901 and 14101 are oriented in opposite directions with respect to the distal threads 14004 and proximal threads 14004. On the other hand, the helically wound strut 14201 is in the same direction relative to the distal threads 14004 and the proximal threads 14005. The engagement features 13903 employed in member 14000 are oriented in a distal direction on struts 13901, and in members 14100 and 14200, the engagement features 14103 and 14203 are oriented in a proximal direction on struts 14101 and 14201, respectively.

Fig. 192 is a picture of a side view of a bone fixation device or member 14000 as reduced to practice.

These described embodiments additionally or in conjunction with axial compression or tension loads respond differently to rotational loads applied in a clockwise or counterclockwise manner. These different behaviors of the mechanism, along with the procedure used, produce the desired therapeutic effect. The winding direction of the struts 13901 and 14101 relative to 14201 can be the same or opposite of the distal threads 14004 and/or the proximal threads 14005. And for varying the application of these features to produce different desired spring, elongation, compression and/or tension responses. Corresponding engagement features are located at opposite or adjacent distal or proximal ends of the struts of the adjacent member or members. These features and their size, shape, location and frequency are configured in various combinations to achieve the desired expansion, tension, rotational stability, diameter expansion or contraction to produce the desired mechanical properties.

Embodiments of members 14000, 14100, and 14200 are depicted as side views for a non-fixation state of a hollow headless screw for bone fixation with an unthreaded, helically deformable center section having a torsional engagement feature. These screws or members have proximal threads 14005 that allow threading into tissue at the treatment site. Distal threads 14004 may have the same pitch, less or more than proximal threads, to produce tensile, neutral or compressive axial loads.

Fig. 143 is a partial side view of a portion of a slot pattern 14300 of a bone fixation device, e.g., the device 14100 shown in fig. 141 having an unthreaded, helically deformable portion with a torsional engagement feature in an unexpanded state. The embodiment shown in fig. 143 illustrates additional variables of the torsional engagement characteristics. For a total of twelve engagement features 14103, the number of two engagement features 14103 shown around the circumference employed herein, as well as the total number of five struts 14101 shown herein, may be varied to achieve desired mechanical properties. The number of engagement features per helical wrap of the strut may vary from 1 to 100 or more depending on the diameter of the screw or tube member and the size of the engagement features. Different numbers of features may produce different torsional responses, elongation characteristics, stress and strain curves, and bending stiffness.

Fig. 144 is a scaled partial side view detail of a portion of a cutback pattern 14300 of a bone fixation device having an unthreaded, helically expandable section with a torsional engagement feature, in an unexpanded state, near the beginning or end of a shear pattern. Radius 14308 (radius AA) and dimension 14407 of diagram 144 illustrate features that have multiple functions. In most cutting patterns, the machined gap or dimension 14407 is minimized. The ends of the cutting pattern may benefit from an increase in radius 14308 (radius AA) and an increase in dimension 14407, or a greater distance between the helical members. The ends of the slot may also benefit from a geometry having a geometry that has a lower strain, such as radius 14308, when the component is loaded. The size or dimension 14307 of the gap (Dim CC) may be different from the minimum machining width, such as about 0.0005 inches (depending on the thickness of the material wall) as large as the pitch dimension 14310(Dim J). The increased dimension 14407 may also facilitate processing steps such as electropolishing, chemical etching, and/or grit blasting. Radius 14308 promotes a clearance area to allow desired media to enter the sidewall of the strut. The remainder of the deformable portion may be deformed or stretched during processing to achieve a desired gap distance or strut separation, such as shown as gap 14502 in fig. 145.

Dimension 14305(Dim M) represents the circumferential dimension of an embodiment in this plan view. Dimension 14306(DimBB) is a measure of the distance between the engagement features 14103. Dimension 14306 may be equal to width dimension 14405(DimS), as described below, or equal to circumferential dimension 14305(Dim M) multiplied by the number of helically wound struts 14101.

The angle 14406 (angle Q) is a measure of the angle of the axially oriented edge of the engagement feature relative to the longitudinal central axis of the screw member. The angle 14406 may vary from zero degrees (which is parallel to the axis 14412 of the component) to parallel to the pitch angle 15007 (angle K) (fig. 150).

The shape and angle of the sides 14402 and 14403 of the engagement feature 14103 may be symmetrical, or may have different shapes and/or angles. The leading edge 14409 of engagement member 14103 has a width or dimension 14405(Dim S) which may be parallel to pitch angle 15007 as shown in fig. 150, or may be at a non-zero angle with respect to pitch angle 15007, depending on the desired function. The width 14405(Dim S) may range from a few thousandths to the value of the circumferential dimension 14305(Dim M) multiplied by the number of posts 14101. The height 14408(Dim O) of the engagement feature 14103 can vary up to the actual maximum of the pitch 14310 (DimJ).

The receiving edges 14401 and 14404 and the complementary edges 14402 and 14403 of the engagement feature 14103 have different contact and relative interaction characteristics depending on the load of the entire construction. For example, the complementary edge 14403 is an effective engagement edge in this design, as shown by interface 14504 of fig. 145. When the deformable portion of the member is loaded, the complementary edge 14403 slides relative to the receiving edge 14404 and possibly against the receiving edge 14404 or in contact with the receiving edge 14404, while a gap or space 14505 is maintained between the receiving edge 14401 and the complementary edge 14402.

Thus, the angle 14406 (angle Q) can affect the interaction of two edges sliding against each other by affecting two forces (dynamic and static friction) acting on the two edges. The angles 14406A and 14406B of the two opposing complementary edges 14402 and 14403 relative to the longitudinal central axis may be the same or different. Similar to the inclined plane, the narrower the angle 14406A, the less force is required to initiate and maintain slip. The surface finish and material type of the edge feature also influence this relationship by affecting the coefficient of friction. The angle 14406A may result in a greater force required to slide the engagement feature relative to the post at an angular value that is parallel to or less than the axis angle. Instead, it may act as a ramp to facilitate sliding of the two edges relative to each other, as shown in fig. 144, at an angle greater than the angle of the axis, e.g., about six degrees.

The complementary edge 14402 does not contact the receiving edge 14401, which is about five degrees depending on the load and angle of the edges shown here. However, if the angle is reduced, as shown in fig. 169, engagement or locking with the respective receiving edges and complementary edges is achieved, effectively limiting expansion of the deformable portion.

Fig. 145 is a partial side view of, for example, a bone fixation device. The device 14100 shown in fig. 141 has an unthreaded, helically deformable segment having a cutting pattern 14300 with a torsional engagement feature in an expanded or loaded state. The elongated state of the cutting pattern 14300 demonstrates the potential behavior of the engagement feature 14103 having edges that meet at the interface 14504 and a gap or gap 14505 between opposing engagement feature edges. This behavior is the result of torsional loading and/or tensile/tensile loading or a combination of both. The total amount of twist along the length of the member about the axis of the tube is limited by the engagement features 14103.

Fig. 146 is a side view of a bone fixation device 14100 in a non-expanded state having an unthreaded, helically-shaped deformable portion with a torsional engagement feature. Fig. 147 is a side view of a bone fixation device 14100 in an expanded state having an unthreaded, helically-shaped expandable section with a torsional engagement feature. Length 14609(Dim DD) is less than length 14709(Dim EE). Loading of member 14100 with external tensile and/or torsional forces results in an increase in length of the configuration depicted in the comparison of member 14100 shown in fig. 146 and 147.

Self-cutting thread features such as 14601 and 14607 may be used on the screws. The non-slotted segment 14602, i.e., those components not present in the slot pattern 14300 with the slots 14102 and pillars 14101, may or may not be present and may have a length that spans a majority of the length of the member 14100. The gaps 14407 may be configured such that they are equal to the expanded gap 14710 for a given loading condition. The components shown in fig. 146 and 147 are merely examples of the inventive concepts disclosed herein. The expandable, torque transmitting, length limiting features described herein may be implemented on any screw, rod, or other means of securing bone tissue, such as the embodiments shown in fig. 148 and 149.

Fig. 148 and 149 illustrate a similar embodiment of the invention as shown in fig. 147 and 148, except that the embodiment shown in fig. 148 and 149 illustrates the above-described features and deformable portion on a headed screw or member 14800 having an unthreaded head 14806. This embodiment may provide a simpler insertion technique by allowing the number of delivery rotations to be as appropriate for the clinician. The more turns, the longer the screw configuration, as the distal threaded end will continue to drive the tissue. Fig. 148 is a side view of a bone fixation device or member 14800 in an unexpanded state having an unthreaded, helically-expandable section with torsional engagement features. Fig. 149 is a side view of a bone fixation device or member 14800 in an expanded state with an unthreaded, helically-expandable section having a torsional engagement feature.

Fig. 150-169 illustrate an example of another embodiment of the present invention. These examples cover features that share the following functions: limiting the extension or stretching of a portion or the entire construction, connecting member or deformable portion. The ability to control the length of the entire structure has several benefits. One such benefit is to allow maximum length to be achieved and then additional axial load to be applied to the bone segments. This additional load may be applied by further rotation of the screw, which will cause the tissue to engage distally and increase the compressive force above that required to pull the screw to the design amount. Clinically this is called pretension. Over time, remodeling of the tissue occurs and this load is quickly absorbed if standard orthopedic screws are used, because little to no remodeling of the tissue is required to reduce the load to net zero force, as screws of static length of less than a millimeter are used. For the embodiments described herein, the load will first be absorbed by the tissue to the point of activating the elongation mechanism, and then the load is applied by the elongation mechanism until the distance is completely relaxed, which may be a few millimeters. The ability to control the expansion state may also prevent over-expansion of the elongated portion, which may be desirable to minimize yielding of the structure.

Fig. 150 is a side view of a portion of a cut groove pattern of a bone fixation device in an unexpanded state having a non-threaded helically expandable section with a torsional engagement feature and an axial length engagement feature. The helical winding of each strut 15001 of this embodiment has only one engagement feature 15003. When tension is applied to the threaded member, it may be desirable to limit the overall expansion or deformation of the deformable portion 15010. Thus, the length limiting feature as shown in fig. 151 may be manufactured by various physical features formed in the undercut 15002 of the engagement feature 15003. As shown in fig. 150-169, the concept of having members that both expand in length and are constrained in such expansion allows for greater tension to be applied without causing changes in length or diameter that exceed a predetermined or designed value.

Referring to fig. 150 and 151, the dimension 15008(Dim R) shown here is the same on each strut 15001, but on each strut 15001, the dimension 15008, the dimension 15012(Dim S) and the dimension 15103(Dim O) may be different. This will change the cross-section of the helically wound component 15010 and the force applied by the engagement features 15003 during torsional loading of the component. Radius 15009 (radius P) may also vary with angle 15006 (angle Q) to maximize the width of the helical member and/or to promote different friction characteristics. The total length 15005(Dim N) of the deformable portion 15010 is limited by the length of the screw, the threaded portion and the head. Angle 15007 (angle K) is the pitch of strut 15001 and is related to dimension 15004(Dim J). Dimension 15011(Dim M) represents the circumferential dimension of the construct. Alternatively, the dimension 15004 may be varied by the deformable portion 15010.

Fig. 151 is a partial side view of portion B of a cutback pattern 15010 of a bone fixation device having a helical expandable segment without threads, partially shown in fig. 150, with a torsional engagement feature 15003 in an unexpanded state and integrated corresponding axial length engagement features 15104A and 15104B. Dimension 15105(DIM T) is the dimension between the elongation limiting engagement features 15104A and 15104B on the torsional engagement feature 15003. Dimension 15105 corresponds to the length that adjacent struts 15001 will move away from each other before extension limiting engagement features 15104A and 15104B fully engage or contact each other and prevent further extension. The dimension 15105 can be varied to adjust the overall deformation or elongation of the entire structure.

Fig. 152-156 illustrate another embodiment of the invention that employs a semi-symmetrical geometry and a slot cut pattern 15210 having a locking or length engagement feature on the engagement side or leading edge of the twist engagement feature. When the twist engagement feature 15203 is loaded in torsion and tension, the limit features 15304A and 15304B contact and limit rotation and length change of the configuration at point 15505.

Fig. 152 is a partial side view of a portion of a cut slot pattern 15210 with cut slots 15202 of a bone fixation device having a helically expandable section or deformable portion without threads, having torsional engagement features 15203 on both leading and trailing edges of the helical strut 15201, and having axial length engagement features 15304A and 15304B on the engaging or sliding edges in a non-expanded state.

Fig. 153 is a partial side view scaled detail of portion D shown in fig. 152 of a cutback pattern 15210 of a bone fixation device having a helically expandable section without threads, with a torsional engagement feature 15203 and axial length engagement features 15304A and 15304B in an unexpanded state. Dimension 15309(Dim T) may be varied to affect the overall length limiting feature of the construction, which is limited by dimension 15306(Dim O) of the length of the engagement feature. Dimension 15312(Zim Z) is the dimension or axial length of the interference feature that engages the offset of features 15304A and 15304B. The dimension 15312 may be set to provide a firm engagement, or may be set to be shallow to provide a weaker or less engaged mechanism, depending on the desired effect. The effective range of dimension 15312(DimZ) is a few thousandths of an inch of dimension 15305(Dim S) of the width of the engagement feature. Dimension 15306 is half the height Dim 14408 of the engagement feature. The relationship between the angle 15310 (angle Q, the angle of the side of the engagement feature 15203 relative to the longitudinal central axis of the construction) and the relative orientation of the axial length engagement features 15304A and 15304B will produce different engagements. It may be arranged to have a sliding engagement until the engagement points do not touch, the load of the final engagement increases, etc.

In this embodiment, the length limiting feature is shown on only one side of the twist engagement feature, but may be placed on the other edge as well or instead. The angle of approach, height and length of the engagement features can be varied to optimize the desired engagement. The depth 15312(Dim Z) may be steep to provide a firm engagement or shallow to provide a weaker or less engaged mechanism, depending on the desired effect. The relationship between the angle 15310 (angle Q) and the relative orientation of the axial length limiting features 15304A and 15304B will produce different engagements. It may be arranged to have a sliding engagement until the engagement points do not touch, the load of the final engagement increases etc.

Fig. 154-156 illustrate the cut pattern 15210 shown in fig. 152 formed on a tube and machined into a configuration. The cut pattern 15210 has length-limiting features 15304A and 15304B. Fig. 154 is a partial side view of a portion of a cutback pattern 15210 of a bone fixation device having a helical expandable or deformable section without threads. A tube having a torsional engagement feature 15203 and axial length engagement features 15304A and 15304B in a non-expanded state.

Fig. 155 and 156 are partial side view scaled details of a portion of the cut groove pattern 15210 of a bone fixation device having a non-threaded helical expandable or deformable section with a torsional engagement feature 15203 and axial length engagement features 15304A and 15304B that engage at point 15505 when in an expanded state under tensile load. Fig. 155 and 156 show the cutting pattern 15210 in a stretched configuration, with the length limiting features 15304A and 15304B engaged at points 15505 such that the length limiting features 15304A and 15304B transmit force from one to the other. This engagement action allows the length-limiting components 15304A and 15304B to distribute axial and torsional forces to adjacent struts 15201 at contact points 15505. The net result of this interference is to limit the elongation and torsional rotation of the entire cut pattern 15210. The engagement feature 15203 has a leading edge side 15605 and a trailing edge side 15606. The definition of leading edge side and trailing edge side generally depends on the particular cutting pattern direction and the loading of the forces applied to the structure.

Fig. 157-159 illustrate another embodiment of the present invention having a pattern of kerfs with kerfs having different geometries or shapes for the twist and length engagement features. The geometry resembles a triangle. The shape of the twist engagement features and length engagement features of the previous embodiments have been similar to trapezoids, rectangles, parallelograms, rhomboids, and the like. The difference in the characteristic geometry of the pattern of cuts 15710 formed by the cuts 15702 may result in less or more material in the cross-section of the helical strut 15701 and affect the resilience of the construction. The geometry may also create a torsional engagement feature 15703 that exhibits a higher yield point and is therefore able to withstand higher loading conditions. Engagement amount or length the length of the engagement features 15704A and 15704B will also have an effect on the amount of load or force that the cut pattern 15710 can withstand before yielding. The number of torsional engagement features 15703 along the length of strut 15701 will also affect the load distribution along strut 15701. The number of twist engagement features 15703 of each winding member is asymmetric. The number and/or location is offset to maximize the cross-sectional area at any point along the helical strut 15701, which gives the cutting pattern a stepped appearance.

Fig. 157 is a partial side view of a portion of a cut groove pattern 15710 of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature 15703 and an axial length engagement feature 15704A/B in a non-expanded state. Fig. 158 is a partial side view of a portion of a cut groove pattern 15710 of a bone fixation device having an unthreaded, helical expandable section with a torsional engagement feature 15703 and an axial length engagement feature 15704A/B in an unexpanded state. Fig. 159 is a partial detail of a partial side view of a portion of a cutback pattern 15703 of a bone fixation device having a non-threaded helical expandable segment with a torsional engagement feature 15703 and axial length engagement features 15704A and 15704B in contact or engagement at a point 15905. In the expanded state. These faces separate from each other upon clockwise rotation, minimizing friction until the engaging members 16004A and 16004B catch or interfere at some point along the deformation, which then transfers the load. During counterclockwise rotation they will engage with a lesser load.

Fig. 160-162 illustrate another embodiment of the present invention having a pattern of slits with cuts having different geometries or shapes of twist and length engagement features. The geometry resembles a triangle. The number of engagement features of each winding member is not symmetrical and is offset so as to maximize the cross-sectional area at any point along the helical strut, which gives the pattern a stepped appearance. The cut groove pattern 16010 with the struts 16001 formed by the cut grooves 16002 employs a length joint member 16004A/B on the trailing edge of the torsion joint member 16003. The leading edge of the twist engagement feature 16003 is minimized and therefore has little to no contact until the length limiting features 16004A/B contact at point 16005. This set of features produces a rotational elongation behavior that is different from other designs. This embodiment has little frictional resistance to elongation before length limiting features 16004A and 16604B are engaged at point 16205.

Fig. 160 is a partial side view of a portion of a cutback pattern 16010 of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature 16003 and an axial length engagement feature 16004A/B, in a non-expanded state. Fig. 161 is a partial side view of a portion of a cutback pattern 16010 of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature 16003 and an axial length engagement feature 16004A/B, in a non-expanded state. Fig. 162 is a partial detail of a partial side view of a portion of a cutback pattern 16010 of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature 16003 and an axial length engagement feature 16004A/B, in an expanded state. The gap 16205 indicates the expansion of the cut pattern 16010 at the cut 16002.

Fig. 163 and 164 depict another embodiment of the present invention that employs two length limiting features. The cut-slot pattern 16310 formed with cut-slots 16302 employs twist-engagement features 16303 having length-limiting dimension features and independent length-limiting features 16404A/B, similar to those previously described.

The twist engagement feature 16303 has a length-limiting dimension feature in the form of a first width or dimension 16406 that is greater than a second width or dimension 16407. This differential orientation of the dimensions of the torsional engaging features 16303 defines interference of the adjacent sides of the torsional engaging features 16303 over the lengthening or expansion of the cutting pattern 16310 and the expansion of the distance 16311(Dim N). In other words, the difference in the dimensions 16406 and 16407 limits the amount of axial travel and force engagement of the edges of the receiving and protruding portions of the twist engagement feature 16303. Dimension 16313(Dim W), dimension 16315(Dim V) and radius 16308(Dim U) define the size and frequency of the twist engagement feature 16303 with axial length-limiting dimensions.

The length limiting features 16404A/B employ a dimension 16412(Dim Z) and a dimension 16414(Dim T) similar to other embodiments described herein. It should be understood that the axial length limiting dimension of the length limiting features 16404A/B and the torsional engagement features 16303 and 102 is redundant. The axial length limiting dimension of the two length limiting features 16404A/B of the twist engagement feature 16303 is independently sufficient to limit the axial length of the cut pattern 16310. In other words, there need not be an axial length limiting dimension of the length limiting feature 16404A/B and the twist engagement feature 16303 to create interference with the side edges of the twist engagement features 16303 and 1603. Thereby limiting the axial length of the cutting pattern 16310. The interference fit between the side edges is sufficient to limit the travel or elongation of the cutting pattern 16310.

Fig. 163 is a partial side view of a portion of a cut groove pattern 16310 having a total length 16311(Dim N) and a pitch 16318(Dim J). Having a final pitch angle 16317 (angle K) of the bone fixation device with a circumference 16315(Dim M) having an unthreaded sinusoidally expandable section with a torsional engagement feature 16303, having an axial length limiting dimension and an axial length engagement feature 116404a/B, in a non-expanded state. Fig. 164 is a partial detailed side view of a portion C of the cutback pattern 16310 of the bone fixation device shown in fig. 163 having an unthreaded sinusoidally expandable section with torsional engagement features 16303. Has an axial length limiting dimension and an axial length limiting feature 16404A/B in a non-expanded state. For example, the radius 16308(Dim U) may be 0.025 inches, which corresponds to the dimension 16406. The value of dimension 16407 may be 0.020, which would result in an interference fit on each of the engagement features.

Fig. 165 and 166 illustrate an embodiment of the invention similar to the embodiment illustrated in fig. 163 and 164, wherein the twist engagement feature employs a length limiting dimension feature by different dimensions or widths of different portions of the twist engagement feature to create an interference fit or an extended stop upon axial expansion, e.g., the different widths of the twist engagement feature prevent the protruding and receiving portions of the twist engagement feature from completely separating from each other. For clarity and by way of example only, in the embodiment shown in fig. 165 and 166, no separate length limiting features, such as those previously described, are employed in the cutting slots of the cutting pattern.

The cut pattern 16510 has struts 16501 that employ torsional engagement features 16503 having length-limiting dimensions or dimensional features formed by an undercut 16502. The angle 16616 and the length of the engagement feature 16503 help define the angle of the force and the surface area over which the force is applied when such length of the torsional engagement feature 16503 limits the size that is engaged. These dimensions may increase or decrease the amount of electrical resistance that is created during axial lengthening of the kerf pattern 16510. Dimensions 16515 and 16518 define, in part, the frequency and size of the engagement features.

Fig. 165 is a partial side view of a portion of a cutback pattern 16510 of a bone fixation device having an unthreaded expandable section with a trapezoidal twist-shaped engagement feature 16503 having a length-limiting dimension feature, in an unexpanded state. Fig. 166 is a partial detailed side view of portion a of the cutback pattern 16510 of the bone fixation device illustrated in fig. 165 having an unthreaded expandable section with a trapezoidal torsional engagement feature 16503 having a length-limiting dimensional feature in an unexpanded state. FIG. 166 depicts dimensions 16605 and 16607 that define increased clearance areas in the cut pattern. This increase in clearance is directly related to the expansion distance before the length of the torsional engagement feature 16503 limits axial deformation of the dimensional restraint configuration. The relative difference in dimensions 16606 and 16604 will create interference between the components and create wedging or limit axial deformation.

Fig. 193 is a photograph of a side view of a portion of a bone fixation device 19300 employing the nick pattern 16510 shown in fig. 165, having an unthreaded expandable section with a trapezoidal twist-shaped engagement feature 16503, the feature 16503 having a length-limiting dimensional feature, in an unexpanded state, as simplified to practice.

Fig. 167, 167A, and 167B depict another embodiment of the invention that incorporates features previously described herein. In this embodiment, the shape of the twist engagement feature having the length-limiting dimension feature is asymmetric. The leading or side edge 16704 of the engagement feature 16703 is angled to slidably engage a slight ramp of increasing length change in angle and the edge 16705 that is at an acute angle to the axis of deformation provides a positive stop. The angle of the edges 16705 also acts as a ramp, applying force to the surfaces together once they are in contact. This asymmetry provides a further means for controlling the torsional force required for axial lengthening of the grooving pattern and the robustness of the axial length limiting characteristics of the grooving pattern.

Fig. 167 and 167A are partial side views of a portion of a cutback pattern 16710 of a bone fixation device having a helical expandable section without threads, the expandable section having a torsional engagement feature with an axial length-limiting dimension feature, in an unexpanded state. Fig. 167B is a partial side view of a portion of a cut groove pattern 16710 of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature having an axial length-limiting dimensional feature in an axial direction in a secured state.

Fig. 167, 167A, 167B, and 167C illustrate a cut pattern 16710 having struts 16701 that employ torsional engagement features 16703 having length-limiting dimensions or dimensional features formed by cut-outs 16702. The torsional engagement feature 16703 employs a length-limiting dimension feature that creates an interference engagement between the side or edge that receives the torsional engagement feature 16703A and the side or edge of the protruding torsional engagement feature 16703B, thereby creating contact points 16705A and 16704 a. The length-limiting dimension feature of the twist engagement feature 16703 is defined in part by the dimension 16712 being larger than the dimension 16713.

Additionally, the front and back sides or edges of the rotational engagement features 16703 are angled to facilitate axial lengthening of the cutting pattern 16710 by having a sliding contact engagement. All or a portion of the undercut 16702 may be machined with a greater width and/or potentially an overall shorter path, thereby simplifying manufacturing and reducing manufacturing time. The angle of the torsional engagement feature 16703 may also facilitate removal of the screw body by adding additional contact pressure along the feature.

The width of the slot 16702 or the size of the cut 16715 (fig. 167C) may typically be in the range of 0.0005 inch to 0.015 inch. The cutting pattern cut 16715 may be adjusted to control the overall length variation of the entire construct. Cut pattern incisions 16715 may be uniform or homogeneous throughout the pattern, or may vary in size throughout the length of cut pattern 16710.

The cutting pattern width or size of the cut 16715 may be manipulated to vary the amount of axial, torsional, and lateral bending motion that the construct may displace before the opposing faces or edges of the cut 16702 contact each other. This is true for all embodiments disclosed herein, at least the general principles are illustrated in figures 214B, 214C, 216B and 216C. For example, fig. 216 shows a cut width 21603 that partially allows for the displacement seen in fig. 216A, 216B, and 216C. If dimension 21603 is increased, the amount of displacement will be increased accordingly. Likewise, if size 21603 is reduced, the amount of displacement will be correspondingly reduced. Embodiments such as those depicted in fig. 214 and 215, as well as other embodiments disclosed herein, have a clearance feature similar to feature 1684 (fig. 168B) that takes on a different dimensional value than dimension 16811, with the ability to decouple the ratio of dimensional displacement from the dimension of the kerf width.

The dimensions 16717 and 16714 are the length/height of the engagement feature 16703. The sizes 16717 and 16714 may vary along the cut pattern 16710 from feature 16703 to feature 16703 or may be the same along the cut pattern 16710 from feature 16703 to feature 16703. Dimensions 16722 and 16723 are corresponding dimensions of dimensions 16717 and 16714, the difference between dimensions 16717 and 16714 and dimensions 16722 and 16723 determining the amount of overlap of the elements, and thus, the amount of engagement of features 16703 serves, in part, to limit the variation in the length of cut pattern 16710. By way of example, dimension 16714/16717 may be 0.015 inches longer than dimension 16722/16723, which would force interference of the respective receiving torsional engagement feature 16703A and protruding torsional engagement feature 16703B. The greater the difference between the dimensions or interference, the greater the engagement. From another perspective, dimensions 16712 and 16713 represent the same engagement.

Dimension 16716 depicts the height or width of the engagement feature 16703. The dimensions 16716 and 16718 and the angle 16724 define a dimension 16725 of an edge 16705 of the engagement feature 16703. Angle 16721 and angle 16724 may be the same or may be different. The angles 16721 and 16724 may affect the amount of engagement and the strength of the tensile force it can withstand by increasing or decreasing the amount of material and surface area involved in the engagement of the features 16703A and 16703B. Angles 16721 and 16724 may also affect the type of engagement. If angles 16721 and 16724 are more parallel to the central longitudinal axis 16706 of the construction, then engagement will occur over a longer axial displacement. Furthermore, if the angles 16721 and 16724 are more parallel to the axis 16706 of the construct, the engagement will have more of a friction fit due to the wedging of the construct. On the other hand, if angles 16721 and 16724 are more perpendicular to axis 16706 of the construct, the engagement will have more stop contact mechanisms.

Angle 16719 represents the pitch of the entire winding member or leg 16701. Dimension 16726 is the width of strut 16701 relative to line or plane 16742 perpendicular to axis 16706. The angle 16720 is the angle of the side or edge 16704 of the torsional engagement feature 16703 relative to the axis 16706 of the construction. The angle 16720 determines, in part, the frictional force exerted on the structure during lengthening or stretching of the structure prior to engagement of the length engagement dimension of the torsional engagement feature 16703. The angle 16720 may be set such that there is little or no contact between the edges of the features 16703 or these opposing surfaces of the sides 16704 (fig. 167A) during the lengthening of the structure. Thus, during lengthening of the construction, little or no friction is caused between the respective and opposite sides 16704 of the respective receiving torsional engagement feature 16703A and the protruding torsional engagement feature 16703B. This angle 16720 depends on the angle 16719 so that it should supplement the motion of the strut 16701 guided by the pitch angle 16719 to achieve the desired effect. The angle 16720 may be set closer to parallel to the axis 16706 if friction is required during a change in the length of the construct.

The above-described features provide an embodiment wherein a first linear side 16704 or 16705 of receiving portion 16703A and a corresponding first linear side 16704 or 16705 of protruding portion 16703B, a second linear side 16704 or 16705 of receiving portion 16703A and a corresponding second linear side 16704 or 16705 of protruding portion 16703B, respectively, are inclined in the same direction relative to the longitudinal central axis 16706 of the device and are non-parallel to each other, opposite the first linear sides of the receiving portion and protruding portion, respectively.

168, 168A, 168B, 168C, 168D, 168E, 168F, 168G, 168H, and 168I are partial views of a portion of another embodiment of the present invention using a slot pattern 16810 of a bone fixation device having a non-threaded helical expandable section having a torsional engagement feature 16803 employing a length limiting dimension feature and separate length limiting features 16804A and 16804B formed by slots 16802. Fig. 168 shows the slot pattern 16810 in an unexpanded state, and fig. 168A shows the slot pattern 16810 in an expanded state. This embodiment is similar to the embodiment shown in fig. 167, but the slot pattern 16810 also employs a length deformation limiting feature on the leading edge or face, similar to fig. 152. The surfaces of length limiting features 16804A and 16804B are angled to promote sliding contact until the feature edges engage during length deformation. The opposing sides or sides of the torsional engagement features 16803 have a wedge shape or an inclined shape such that upon axial deformation of the slot pattern 16810, the sides exert a force for engagement of the length limiting features 16804A and 16804B.

Figure 168A depicts a construct in tubular form deformed in a stretched or expanded state. Length limit features 16804A and 16804B are shown in an engaged position. The corresponding opposing faces 16805A and 16805B of the torsional engagement feature 16803 engage or interact to generate a force vector that increases the force on the engagement of the length limiting features 16804A and 16804B. The interaction of the faces 16805A and 16805B of the torsional engagement features 16803 serves, in part, to not only increase the surface area of interference, but also define a geometry such that the axial and torsional forces generated are translated into forces that engage the entire slot pattern 16810. Thus, not only are length limiting features 16804A and 16804B loaded, but the entire winding member or strut 16801 of pattern 16810 is loaded. This distributed or shared load characteristic is similar for the embodiments shown in fig. 163-169C disclosed herein.

The width or cut of the slot pattern 16810 can be non-uniform or the length of the slot 16802 can vary. The size of the notch 16811 may generally be in the range of 0.0005 inches to 0.015 inches. The cut 16811 can be adjusted to control, in part, the overall length variation of the entire construct. The cuts 16811 can be uniform across the pattern 16810, or can vary in size across the length of the pattern 16810. The cuts, gaps or dimensions 16811, 16812, and 16813 illustrate one embodiment wherein the width of a slot 16802 or slot 16802 varies throughout the pattern 16810 and particularly in the area of a feature 1684 (fig. 168C). Further, dimensions 16812 and 16813 may vary from feature 16803 to feature 16803 along pattern 16810. For example, these dimensions may decrease with features near the ends of the cutting pattern 169910 on either end. Example dimensions included herein are for features located in the middle of the pattern, and as the features approach the two ends, they may reduce the gap dimension, as shown in fig. 169B, where dimension 16921 is reduced to dimension 16921 a; as shown in fig. 169B. Size 169912 decreases to size 169912A; dimension 1613 is reduced to dimension 1913A. The amount of variation will depend on the stiffness of the wrapping member and the length of the wrapping member 16901 as well as the number of strut features 169903. This reduction in size is to optimize the engagement of the features because the displacement of the formations is not uniform across the length of the cutting pattern 16810 and the displacement is smaller toward the ends of the cutting pattern 16810.

Dimension 16816 is the length/height of the engagement feature 16803. The dimension 16816 can vary between features 1683 along the pattern 16810, or can be the same throughout the pattern 16810. Dimension 16819 is a corresponding dimension of dimension 16816. The dimension 16819 can vary between features 1683 along the pattern 16810, or can be the same throughout the pattern 16810. The difference between dimension 16816 and dimension 16819 determines the amount of overlap of features and, thus, the amount of engagement of portions of the features 16803 that act to limit distortion, such as a change in length of the cut pattern 16810. By way of example, dimension 16816 may be 0.015 inches longer than dimension 16819, which would force interference of the respective receiving torsion engagement feature 16803A and the protruding torsion engagement feature 16803B. The greater the difference in these dimensions or interference, the greater the area of engagement.

Dimension 16817 depicts a height or width of the engagement feature 16803. Dimension 16821 and dimension 16817 and angle 16822 (fig. 168C) define a dimension 16820 of engagement feature 1683. Angle 16825 indicates that the spacing of posts 1681 relative to a line or plane 16842 perpendicular to the central longitudinal axis 16840 of the structure changes as the length of the structure increases or decreases. Changes in angle 16825 due to changes in length affect the gap distance 16812 and angle 16824 to ensure a desired or optimal interface between adjacent or opposing faces 16804A and 16804B.

The angle 16822 can affect the amount of engagement and the strength of the tensile force it can withstand by increasing or decreasing the amount of material and surface area involved when the opposing features 16803A and 16803B are engaged. The angle 16822 may affect the type of engagement. If angle 16822 is more parallel to the build axis, engagement will occur over a longer axial displacement. If angle 16822 is more parallel to the longitudinal central axis 16840 of the construct, the engagement will have more of a friction fit due to the wedging of the construct. On the other hand, if the angle 16822 is more perpendicular to the axis 16840 of the construct, engagement will have more stop contact mechanisms. Angle 16823 is an angle relative to an edge of a winding member or strut 16801 of pattern 16810.

Angle 16825 represents the pitch of winding member or post 16801 over the entire length 13837 (fig. 168G) of pattern 16810 relative to a line or plane 16842 that is perpendicular to axis 16840. Angle 16824 is the angle of the rotational engagement feature relative to axis 16840 of the construction. The angle 16824 determines, in part, the frictional force exerted on the structure during extension or stretching from the state 16837 to the state 16839 of the state prior to engagement of the length limiting members 16804A and 16804B (fig. 168G, 168H, and 168I). Angle 16824 may be set such that there is no or substantially no contact between the surfaces of features 1684A and 16804B during extension, which would not result in friction. This angle 16824 is dependent on the angle 16825 such that it must complement the movement of the wrap or post 16801 as directed by the pitch angle 16825 to achieve the desired effect. If friction is required during a change in the length of the construct, angle 16824 may be set closer to parallel with axis 16840.

168-168I illustrate an embodiment having a projection, projection or feature 16804A and a corresponding projection or feature 16804B that function, in part, to control rotational and axial length changes of the construct. The features 16804A and 16804B are defined by dimensions 16814, 16815, and 16818 that partially define the feature 16804 with a length gap 16813 and a rotation gap 16812. The length limiting features or protrusions 16804A and 16804B are further defined by angles 16825 and 16824. Dimensions 16818 and 16814 may be changed to adjust the engagement force and resistance of length limiting features 16804A and 16804B. Dimensions 16814, 16815, and 16818, and angle 16824 also define gap dimensions 16812 and 16813.

In certain embodiments, dimension 16814 on the outer surface 16842 of the construct (fig. 168F) may be in the range of 0.010 to 0.100 inches. In certain embodiments, dimension 16913 on the outer surface 16842 of the construct (FIG. 168F) is in the range of 0.010 to 0.200 inches.

In operation, during axial deformation, such as extension or compression of a structure, the displacement of length limiting members 16804A and 16804B from a relaxed state to a stressed state, i.e., the direction from a low energy state to a high energy state, is the axial direction (as indicated by arrow 16828 (fig. 168D)) and the rotational direction (as indicated by arrow 16827), respectively. The size of the gaps 16813 and 16812 and the number of engagement features 16803 employed over the length of the strut 16801 determine how much free space or unlimited length of movement exists before the length limiting features 16804A and 16804B engage.

Angle 16824 partially controls the interference, e.g., lengthening, of an edge or surface 16804A 'of feature 16804A with an edge or surface 16804B' of feature 16804B during deformation. In line with angle 16824, the edge or surface 16804A 'of feature 16804A and the edge or surface 16804B' of feature 16804B are shown as parallel to facilitate minimal contact during length changes.

The minimum gap dimension 16811 described by the respective faces 16805A and 16805B of the torsional engagement features 16803 is between 0.0005 and 0.003 inches. This small gap 16811 increases the overall lateral bending stiffness of the construction as the edges contact each other under bending and change the moment arm or leverage point of the bending moment. Having a gap 16813 or length limiting members 16804A and 16804B in the middle of the tabs or length limiting members also contributes to a more rigid lateral bending configuration. The wedge angle 16822 also contributes to a stiffer construction in the lateral bending. When angle 16822 is approximately 45 degrees from axis 16840, an interference wedge is created to resist bending along central axis 16840. If the tab characteristic angle 16824 and the angle 16822 are parallel to the central axis 16840, there will be little or no interference during bending about the central axis 16840 of the structure.

Referring to fig. 168D and 168E, as the construction lengthens in the direction of arrow 16828 and rotates in the direction of arrow 16827, the gaps 16812 and 16813 decrease. Likewise, as the construct lengthens in the direction of arrow 16828 and rotates in the direction of arrow 16827, the size of gap 16811 also increases.

Fig. 168G through 168I illustrate the progression of the construct from the relaxed shortened state 16837 to the intermediate length state 16838 to the extended or limited length state 16839, which is the same as but in greater detail than that shown in fig. 168D and 168E.

These figures show that the progression of gaps 16811a, 16811B, and 16811C becomes greater as the construct transitions from state 16837 to 16838 to 16839. On the other hand, these figures show the progression of the gaps 16812A, 16812B, and 16812C, and the gaps 16813A, 16813B, and 16813C become smaller as the configuration transitions from states 16837 to 16838 to 16839.

FIG. 168H depicts a configuration in a state 16838 between fully relaxed and fully extended. The gaps 16812B and 16813B are not zero in dimensional length, i.e., the respective surfaces forming the gaps do not contact each other. The size of the gaps 16812B and 16813B remain non-zero for the extended period of the device until the extended state 16839 is reached. The absence of contact between the surfaces forming these gaps reduces the force required to elongate the construct compared to designs in which the surfaces slide or slide relative to each other. Due to the resultant vector of the axial force 16828 and the rotational force 16827, the angle 16824 is designed to match the direction of motion. Faces 16804A 'and 16804B' cannot contact each other until reaching the designed extended state 16839, at which point they contact at point 16845 (fig. 168I).

The above inventive designs and principles for controlling friction of opposing surfaces of torsion and length limiting features, e.g., eliminating, reducing or increasing friction, e.g., shortening to an elongated state, from a low to a high stress state, and vice versa, and/or combinations thereof, as the structure transitions between different states are applicable to all other fixation embodiments disclosed herein.

In certain embodiments, dimension 16811A may be larger, such as 0.005-0.015 inches, in order to reduce the limited lateral bending about the central axis 16840 of the structure. The nature of increasing this dimension to produce greater lateral bending motion is shown in fig. 216B and 216C.

FIG. 168F depicts a partial cross-sectional view of the embodiment in a non-expanded state. This view is used to illustrate the difference in size from the outer surface 16842 of the pattern 16810 to the inner surface 16841 of the pattern 16810 for the same feature of the pattern 16810. For example, a portion of the feature 16803 has a dimension 16834 on the outer surface 16842 that is greater than a dimension 16835 of the same portion of the feature 16803 on the inner surface 16841. The ratio or difference depends on the outer and inner diameters of the construction and the axial and rotational cutting angles described with respect to fig. 195-208. Each feature of the structure is affected by these variables such that the dimensional values described herein with respect to, for example, the outer surface of the structure, may not be consistent across the cross-section of the structure. Such variations in dimensions can affect the functional design of the features and the stress and strain conditions at each respective point.

For example, in this embodiment, the dimension 16814 on the inner surface 16841 shown in fig. 168F is less than the dimension 16814 on the outer surface 16842 shown in fig. 168F and in fig. 168B, 168D, and 168H. This design feature helps feature 16804 on inner surface 16841 to close or contact an opposing face element before feature 16804 on outer surface 16842. The control dimensions to be considered in any design must include the interior surface material dimensions and interfaces to predict the behavior of the build. Similar to the friction and wedging design considerations discussed above in the engagement tab angles 16824 and 16822, the cross-sectional profile such as that shown in fig. 195-. The dimension substantially parallel to axis 16840 of the construct will remain similar from the outer diameter to the inner diameter when the cutting axis is perpendicular to a tangent to the outer diameter. The radial or circumferential dimension varies more from the outer diameter to the inner diameter.

The above-described features provide an embodiment wherein the first linear side 16804A/B or 16805A/B of the receiving portion 16803A and the corresponding first linear side 16804A/B or 16805A/B of the protruding portion 16803B, the second linear side 16804A/B or 16805A/B of the receiving portion 16803A and the corresponding second linear side 16804A/B or 16805A/B of the protruding portion 16803B, opposite sides of the first linear sides of the receiving portion and the protruding portion are inclined in the same direction relative to the longitudinal central axis 16840 of the device and are not parallel to each other.

Opposing surfaces 16805A and 16805B of the torsional engagement feature 16803 defined by the angle 16822 have a resultant force vector 16846 (fig. 168D and 168H) created by the axial force 16828 and the torsional force 16827. The resultant force 16846 is used to further engage length limiting members 16804A and 16804B and to decrease dimension 16813abd16812 by translating or applying a force in a non-axial direction, thereby increasing the force that generates the mechanism. This wedging effect or force 16846 distributes the load in a manner that increases the overall configuration axial tensile load that it can withstand. Further, because angle 16824 defines opposing surfaces of length limiting features 16804A-16804B, wedging is only on rear surfaces 16805A and 16805B of torsion engagement feature 16803. When the torsional load is reversed, the mechanism can easily disengage and return to its original shortened, relaxed state. When features 16804A and 16804B are engaged, the length of contact that limits the opposing edges or faces of features 16804A and 16804B when features 16804A and 16804B are engaged creates two separate force vectors in the directions shown by arrows 16846A and 16846B.

It will be appreciated that after implantation of the devices or bone fixation devices disclosed herein and release of the active axial compression of the inventive devices, all of the cuts or incisions of the cutting pattern of the devices may not necessarily return to their original or low stress state. This may be due in part to the resistance between the proximal and distal engaging portions of the device and the bone prosthesis in which these portions are implanted. For example, with the embodiment shown in fig. 168-168I, gap 16811C may return completely to gap 16811a after implantation of the device or bone fixation device disclosed herein and release of the active axial compression. However, the gap 16812C can be retransmitted as the gap 16812C and not to the gap 16812A.

In certain embodiments of the present invention, any of the bone fixation devices disclosed herein employ a torsional or radial deformation limiting feature having asymmetric radial and length elements, and the yield force vectors are in three different directions.

169, 169A, 169B, and 169C are partial side view scaled details of a portion of the cut groove pattern 169910 of a bone fixation device having a helically expandable segment without threads, employing length limiting dimension features and independent length limiting features 16904A/16905B and 16905A/16975B on opposite sides or edges of the torsional engagement feature 16901 on the strut 16901 formed by the cut 16928. Fig. 169, 169B, and 169C show the nick pattern 1699 in a non-expanded state, and fig. 169A shows the nick pattern 169910 in an expanded state. This embodiment is similar to the embodiment shown in fig. 168, but further employs a length deformation limiting feature on the trailing edge or face similar to fig. 160.

The opposing faces or surfaces of the twist engagement features 169903 forming the length limiting features or tabs 169904A and 169904B are angled to promote sliding contact until the length limiting features 169904A and 169904B engage during length deformation. The opposing surfaces or surfaces of the torsional engagement features 169903 forming the length limiting features 169905A and 169905B engage upon axial deformation and also apply a length deformation limiting engagement. The faces or surfaces of the torsional engagement features 169903 are angled to provide slidable engagement until the relatively perpendicular edges of the length limiting features 169904A/169904B and 169905A/16975B with respect to the longitudinal central axis 16940 contact and effectively resist axial deformation. The length limiting engagement feature, as well as all other such features described herein, serve not only to limit the overall length of the construct, but also to increase the axial tension that the construct can withstand before permanently deforming.

Fig. 169A depicts a configuration of a tubular form deformed in a stretched or expanded state. The length limiting features 169904A/169904B and 169905A/169905B are shown in an engaged state. The feature planes have both sloped surfaces to facilitate deformation and substantially parallel engagement surfaces to limit length deformation. These features are both anterior and posterior to the twist engagement feature 169903. The deformation limiting feature may limit both length and torsional deformation, as well as total deformation in axial and rotational motion.

The cuts or widths of the kerfs 16911 of the cut pattern 169910 may vary or be non-uniform over the length of the kerfs 169902. The slits 169911 or width typically range in size from 0.0005 inch to 0.015 inch. The size of the cut pattern cuts 1699 can be adjusted to control overall length variations of the overall structure. The size of the cut pattern cuts 1699 may be uniform throughout the pattern 169910 or may vary in size throughout the length of the pattern cut 169910. The gaps or dimensions 169912, 1913 illustrate an embodiment in which the size cut pattern cuts 16931 vary throughout the pattern 1699. Further, dimensions 169912 and 169913, as well as dimension 16921, may vary along pattern 16810 from feature 169903 to feature 169903. In certain embodiments, dimension 1913 on the outer surface of the construct is in the range of 0.010 to 0.200 inches.

Dimension 16972 is the length/height of the engagement feature 169903. Dimension 1699 may vary from one feature to another along pattern 169910 or may be the same throughout pattern 169910. Dimension 16919 and dimension 1699 are respective dimensions for determining the engagement of the length limiting features 169904A/169904B and 169905A/16905B. The difference between dimensions 1699 and 16919 determines, in part, the amount of overlap of features 169904A/169904B and 169905A/169905B and, therefore, the amount of engagement of features 169904A/169904B and 169905A/169905B. By way of example, length 1699 may be 0.015 inches longer than dimension 16919, which will then force features 169904A/169904B and 169905A/169905B to interfere. The greater the difference between dimensions 1699 and 16919, the greater the area of bonding material.

Dimension 16975 describes the height or width of the torsional engagement feature 169903. The dimensions 16923, 16901, 1914, 19618, 16901, and 16931, and the angle 16975 partially define the engagement features 16904A/16931B and 16905A/16975B. These dimensions may be uniform from feature 169903 to feature 169903, or they may vary between features 169903 over the entire length of the cut 16904 of the pattern 1699. Their size is limited by design gaps 1693, 1913, 16921, and 16904, and the size of the engagement structures is also limited by dimensions 1699 and 16901. These dimensions depend on the spacing, diameter and number of features 169903 along the length.

Angle 16924 represents the spacing of the winding members or struts 16901 of the pattern 16901 relative to a line or plane 16942 perpendicular to the longitudinal central axis 16940. Angle 16926 and angle 16925 are the angles of the torsional engagement feature 16901 relative to the longitudinal central axis 16940 of the construct. The angles 16925, 16926, 16929, 16928 and 1699 determine the frictional force exerted on the structure during lengthening or stretching of the structure prior to engagement of the length limiting features 169904A/169904B and 169905A/16939B. The angles 16925, 16926, 16929, 16928 and 1699 can be set so that there is no contact between the faces during extension, which will result in little friction when the structure is extended. Angle 16925 depends on pitch angle 16924 so that it must supplement the movement of the wrap or brace 16901 guided by pitch angle 16924 to achieve the desired effect. If friction is required during a change in the length of the construct, angle 16825 may be set to an angle closer to parallel with axis 16940. The dimensions 16931 and 16932 separated by dimension 169930, set angles 1699 and 16928 are additional control surfaces used by this embodiment to control friction during build elongation. The length limiting features 169904A/169904B and 169905A/169905B have additional contact surfaces that affect the frictional response of the structure during lengthening.

Fig. 169-169C illustrate an embodiment having a feature 169903 which controls the rotational and axial length changes of the structure. Features include 169903, length gap 169913, and rotational gaps 16921 and 16906. The dimensions 16918, 16923, 1914, 1697, and 16901 can be modified to adjust the engagement force and resistance of the length limiting members 169904A/169904B and 169905A/169905B. The gap dimensions 169913, 16904, 16921, and 16938, and angles 16925, 16926, 16929, 16928, and 1699, in part, define a gap length that controls the friction generated between the surface of the receiving portion 16904a and the surface of the projecting portion 169903B of the feature 169903. The movement of the length limiting members 169904A/169904B and 169905A/169905B both axially and rotationally during the lengthening of the structure.

The size of gaps 1693, 169913 and 16921 and the number of twist engagement features 169903 over the length of strut 16901 determine how much free space or unlimited length of movement there is before engagement of length limiting features 169904A/169904B and 169905A/169905B. Angles 16925 and 16992 9 control the interference or interaction of the surfaces of length limiting features 169904A and 169904B during the extension of the construct. In fig. 169B, opposing surfaces 169904A 'and 169904B' of length limiting features 169904A and 169904B, respectively, coincide with angles 16931, 16926, 16929, 16928 and 1699, respectively, substantially parallel to the direction of motion, i.e., parallel to axis 16940 during lengthening when rotational and axial forces are applied to the structure to promote minimal contact during length change.

The leading and trailing edges of the engagement features 169903 depict a minimum gap dimension 1699 of 0.0005-0.003 inches. This small gap 1699 increases the overall lateral bending stiffness of the construction as the edges contact each other under bending and change the moment arm or leverage point of the bending moment. Having gaps 16901 and 16921 between the tabs or length limiting members 169904A/169904B and 169905A/169905B contributes to a stiffer curved configuration. The non-axial angles 1925, 16926, 16929, 16928 and 1699 also contribute to the rigid configuration in transverse bending. As angles 16925, 16926 approach 45 degrees with respect to axis 16940, an interference wedge is created that resists lateral bending along central axis 16940. If the corners 16924 and 16924 of the projections 169904A/169904B and 169905A/16975B are parallel to the central axis 16940, there will be no interference during bending about the central axis 16940 of the structure. As the construct lengthens and rotates, gaps 1913 and 16921 decrease. When the designed length is reached, the gap will close.

The embodiment illustrated in fig. 169-169C differs significantly from known cutting patterns (such as that shown in fig. 212) because of the predetermined angles 16925, 16926, 16929, 16928 and 1699 of the clearance features 1913 and 16921 and the engagement features 169936, 169937, 16934 and 16935. These features enable the construct to be extended to a predetermined length with minimal friction and then resist further extension during continuous loading, which is typically clinically visible for such devices. This embodiment functions without yielding and is able to fully return to the original state while applying clinically beneficial loads to the fixed bone tissue, as compared to standard solid screws.

The embodiments illustrated in the above figures are not limited to the particular feature shapes shown in the figures. For example, while the tangential mode shown in fig. 167 employs a twist-engagement feature having substantially three sides; however, the engagement features are typically three-sided. The cut pattern shown in fig. 168 employs a twist-engagement feature having substantially five sides. And within the scope of the invention, the cut pattern shown in fig. 169 employs twist-engagement features having substantially seven sides, which may be modified to use three, four, five, six, seven, eight, or nine sides.

In certain embodiments of the present invention, any of the bone fixation devices disclosed herein employ a torsional or radial deformation limiting feature having radial and length elements that are used in a radial aspect of a single torsional or radial deformation limiting feature rather than in an axial direction of a single torsional or radial deformation limiting feature.

The embodiment disclosed at least with respect to fig. 168 and 169 employs a plurality of radial deformation limiting features (e.g., 16803 and 169903) formed along the length of the helical struts (e.g., 16810 and 16968), each of the plurality of radial deformation limiting features being formed by an asymmetrically-shaped receiving portion (e.g., 16803A and 169903A) defined by opposing sides of the helical struts and an asymmetrically-shaped protruding portion (e.g., 16803B and 169903B), the shape of the receiving portion being different from the shape of the receiving portion. Further, the respective asymmetric shapes of the receiving portion and the protruding portion facilitate translation relative to each other over a defined axial and/or radial length, and once that length is achieved, further movement or translation relative to each other is resisted or limited by contacting and engaging the opposing features.

Fig. 170 and 171 depict another embodiment of the present invention, wherein a wound strut 17001 employs a stepped or repeating stepped torsional engagement feature 17003 formed by a cut 17002. Stated alternatively, the cutback pattern 17010 employs a torsional engagement feature 17003 having the form or shape of the torsional engagement feature on the torsional engagement feature 17003. Another way of describing the nick pattern 17010 would be to use both torsional engagement features 17103A extending from the trailing edge 17122 of the strut 17001 and torsional engagement features 17103B extending from the leading edge 17121 of the strut 17001. Gap 17107 represents a kerf pattern with a width that increases near the ends of the pattern. This may relieve stress on the structure as it transitions from a cut channel type to a solid, non-cut section or portion. This function also simplifies post-processing such as electropolishing, etching and grit blasting.

The overall bending stiffness, axial stiffness, and rotational stiffness characteristics of the kerfs pattern 17010 may be different from other embodiments described herein. Each torsional engagement feature 17003 may employ any or all of the previously disclosed feature sets. Fig. 170 is a partial side view of a bone fixation device having an unthreaded expandable section in a non-expanded state. Fig. 171 is a partial side view of a portion of a cut groove pattern of a bone fixation device having an unthreaded expandable section in an unexpanded state.

Features described throughout this disclosure may be used with features from any and all embodiments disclosed. The locking mechanism or length engagement feature, twist engagement feature and helical pattern may all be used interchangeably and the figures are illustrative of possible embodiments and do not fully encompass the scope of all variations of the invention.

Fig. 172-175 illustrate other embodiments of the present invention. In these embodiments, the deformable portion of the member is configured to not generate a rotational force.

Referring to fig. 172 and 173, the cut pattern 17210 employs a winding member 17201 with the winding member 17 following a sinusoidal path along the longitudinal axis of the pattern 17210 formed by the cut slots 17202. The deflection of member 17201 cooperates to produce no net rotational moment. Optional vertical spline members 17223 placed at the peaks and valleys vertices of member 17201 serve to limit the radial deformation forces exerted on member 17201.

Each portion 17224 of winding member 17201 between spline members 17223 acts like a curved beam and thus, like a spring, lengthens as it deforms to a straight or axial configuration. The number of winding members 17201 may vary between 1 and 100, but depends on the width 17307 of the members 17201, the width of the cut slots 17202, the magnitude of deflection 17308 of the winding members 17201, the diameter of the tubular form of the cutting pattern 17210. The wound members 17201 around the circumference of the tubular form of the structure act in parallel as springs, changing the spring constant accordingly.

In the substantially parallel configuration shown in fig. 172 and 173, the springs are arranged parallel to each other and the resulting spring constant is higher than if a single strut or spring of width 17307 were employed throughout the entire length of the deformable portion. The bending pattern or profile of the wrapping member 17201 can vary to distribute bending strain along the longitudinal axis in a desired manner. The width 17307 of wrapping member 17201 and the length of segment 17224 may be the same or may vary around the circumference of the tubular form of construction. Fig. 172 shows two spring mechanisms or portions 17224 in series, the number of which depends on the overall length of the cut pattern 17210, but can vary from 1 to 100, changing the spring constant accordingly. For example, fig. 173 shows four spring mechanisms or portions 17224 in series, each portion 17224 having a different variation than that shown in fig. 172.

Fig. 172 is a partial side view of a tubular form of a cut groove pattern 17210 of a bone fixation device having a non-threaded sinusoidal expandable section in a non-expanded state. Fig. 173 is a partial side view of a bone fixation device having an unthreaded sinusoidal expandable section in an expanded state.

Fig. 174 and 175 illustrate alternative embodiments of the inventive concepts described with respect to fig. 172 and 173. Referring to fig. 174 and 175, the cutting pattern 17410 employs a winding member 17401 having an angled path along the longitudinal axis of the pattern 17410 formed by the cutting flutes 17402. The deflection of member 17401 cooperates to produce no net rotational moment. As shown in fig. 175, a longitudinal axis force, indicated by arrow 17525, is applied to the cutting pattern 17410, with the diameter 17526 being reduced relative to the diameter 17527 of the partial construct not using the cutting pattern 17410. Brace members 17401 may be uniform or have different widths 17404.

Fig. 174 is a partial side view of a cutting pattern 17410 of a bone fixation device having an angled, expandable section without threads in a non-expanded state. Fig. 175 is a partial side view of a cutting pattern 17410 of a bone fixation device having an angled, expandable segment without threads in an expanded state.

Fig. 176 and 177 depict another embodiment of the invention in which the cutting pattern 17610 employs a nick 17602 having an undulating or chevron shape with struts 17601a and 17601B and a connecting portion 17604. As an axial load is applied to the slot pattern 17610, the dimension 17703 between similarly oriented slots 17602 increases. Deflection is controlled by several variables, including the wall thickness of the tube. Width 17606 of struts 17601a, 17601B; length 17605 of struts 17601a, 17601B; the angle of the struts 17601a, 17601B relative to the longitudinal central axis; the angle of strut 17601a, 17601B relative to adjacent strut 17601a, 17601B; the number of struts 17601a, 17601B around the circumference; the number of struts 17601a, 17601B along the axis of the structure; the diameter of the tubular form of the cutting pattern 17610.

The flared portion has a shear pattern 17610. The cut pattern 17610 has struts 17601a and 17601B that are angled relative to the axis. The cut groove pattern 17610 the struts 17601a and 17601B are shorter than the circumference of the body. The continuum of cut pattern 17610 has angled struts 17601a and 17601B that terminate at connecting portion 17604. The angled struts 17601a and 17601B provide spring force to achieve a therapeutic effect. The angled struts 17601a and 17601B have alternating angles about the circumference of the body. Struts 17601A and 17601B are axially parallel with respect to each other prior to application of an axial load. As the body or slot pattern 17610 lengthens, the relative angles of the struts 17601a and 17601B diverge from one another. During axial loading, the engagement portions 17604 at the ends of the struts 17601a and 17601B increase relative to each other over an axial separation distance. The overall nature of the bending, rotational and axial stiffness may differ from other embodiments disclosed herein. Variations of the cutting pattern 17610 are considered to be included in the present disclosure.

Fig. 176 is a partial side view of a cut pattern 17610 of a bone fixation device having an unthreaded expandable or deformable section in a non-expanded state. Fig. 177 is an enlarged partial side view of a cut pattern 17610 of a bone fixation device having an expandable section without threads in an unexpanded state. Fig. 178 is a side view of a bone fixation device 17800 in a non-expanded state, the bone fixation device 17800 being inserted into two reduced bone segments 501A and 501B. The illustration is similar to that of fig. 5, and the screws or connecting members are similar to the embodiment shown in fig. 139 and 140. The shaft of member 17800 has a deformable portion 17606 provided at one end of the screw so that the remaining portion 17807 is uncut and less flexible. The less flexible portion 17807 serves to engage the bone segments 501A, 501B in the compressed region 502. The less flexible portion 17807 may be threaded or unthreaded. The screw may be configured with any distal thread 17804 suitable for the type of tissue it engages, such as cancellous or cortical thread types. The proximal head 17805 may also be used with any set of functions to optimize clinical use, such as a head, headless, threaded, self-tapping, etc.

179-191 depict additional embodiments of the disclosed invention wherein the therapeutic mechanism of action employs multiple components to achieve a tension rod spring assembly wherein the spring is in a compressed state rather than in a stretched state. These embodiments may use various compression spring designs such as those shown in fig. 186-191, including but not limited to compression springs, lock washers, spring washers, wave springs, hollow frustoconical Belleville ring rings, conical springs made from spiral wound wire, and the like. The spring wire used in some of these embodiments may have any cross-section; such as a cross-section. Such as circular, flat, rectangular, oval, square, etc. The end configuration may be conventional, grounded, varied pitch, wound, square or any other suitable configuration. The spring configuration may utilize any known configuration, including but not limited to; constant pitch, conical, barrel, hourglass or variable pitch. The spring may be made of a wound wire and treated to maintain its profile. The spring may be cut or machined from bar stock or tubing. Outer diameter, inner diameter, average diameter, wire diameter, free length, solid length, deflection, pitch, material and material processing are all variables that can be used to control spring rate and stress concentration in a design to achieve a desired force distribution and geometry.

Belleville-shaped annular rings of hollow truncated cones may be advantageous in certain applications because they are capable of absorbing external axial forces that react with each other. The cross-section of the spring member is generally rectangular. Belleville springs are designed for higher loads with less deflection. They may be used individually or in groups. When using springs in sets, friction must be taken into account. The springs may be configured in a series arrangement, i.e. arranged opposite each other, the resulting spring constant of the set being lower than the spring constant of the individual springs. Conical springs made of helical threads with a constant gap between the active coils may be advantageous in certain applications because they are able to absorb external reaction forces exerted on each other along their axes.

Fig. 179-183 depict an embodiment of the present invention in which bone segments 501A and 501B having a compression region 502 are brought together and sharply compressed over time by a screw member of the present invention.

Fig. 179 shows the spring or deformable portion 17906 of the member 17900 in a compressed/unexpanded/loaded state, wherein a compressive force is applied to the compression zone 502 of the bone segments 501A and 501B in the direction indicated by arrow 505. The head of the screw 17907 transmits the compressive force generated by the spring 17906 in the direction shown by arrow 505 to the bone segments 501A and 501B to the compression region 502 by engagement of the distal threaded portion 17904 of the screw body 17900. The compression spring 17906 shown here is a canted washer type spring that acts on the bone surface. Head 17907 of screw 17900 and spring 17906 may remain on the surface of bone segment 501B. The screws in FIGS. 179-185 may be hollow or solid screws, and these screws may be constructed with any distal thread 17904 suitable for the type of tissue they engage, such as cancellous or cortical self-tapping types.

Fig. 180 is a side view of a bone fixation device 18000 in an expanded state, the bone fixation device 18000 inserted into two reduced bone segments 501A and 501B. A helical conical spring 18006 engages the head 18007 of the screw 18000 and a counter bored feature 18008 in the bone 501B. This configuration allows the screw head 18007 and spring 18006 to be tangent to and/or below the surface of the bone 501B within the backdrilling feature 18008. The use of a conical spring can minimize the height of the spring 18006 required to produce a given force required. Fig. 181 is a side view of a bone fixation device 18000 inserted into two reduced bone segments 501A and 501Bb in a non-expanded state.

Fig. 182 is a side view of a bone fixation device 18200 inserted in a compressed state into two reduced bone segments 501A and 501B. The spring element 18206 is positioned within a recessed washer 18209 that is submerged in the counter-drilled bone feature 18208. The lip 18210 of the washer 18209 rests on the surface of the bone 501B. The head 18207 of the screw 18200 may be designed to reside within or tangent to the surface of the lip 18210 of the pocket washer 18209. The head 18207 of the screw 18200 may be flush with the lip 18210 of the washer 18209 (fig. 182), on top of the lip 18210 of the washer 18209 (fig. 183), or may be recessed within the pocket washer 18209. The diameters of the spring 18206 and the pocket washer 18209 can be varied to accommodate a minimum or smaller diameter bore, as shown in fig. 185. The desired spring force can be met by varying standard spring parameters, compression length, pitch, diameter, cross-section, material, shape and other parameters.

Fig. 183 is a side view of a bone fixation device 18300 inserted into two reduced bone segments 501A and 510B in a compressed state. The spring elements 18306 are positioned within pocket washers 18309 that are submerged within the counter bored features 18308. The lip 18310 of the washer 18309 is located on the surface of the bone 501B. The head 18307 of the screw 18300 may be designed to reside on the surface of the lip 18310 of the pocket washer 18209. The diameters of the spring 18306 and the pocket washer 18309 can be varied to accommodate a minimum or smaller diameter bore, as shown in fig. 185.

Fig. 184 is a side view of a bone fixation device 18400 in an expanded state, and fig. 185 is a partial cross-sectional side view of the bone fixation device 18400 in an expanded state in accordance with an aspect of the invention.

The spring elements 18406 are positioned within a pocket washer 18409 having a lip 18410. The head 18407 of screw 18400 may be designed to reside within a recess 18409A of pocket washer 18409. Head 18407 employs tool interface 18503 to rotate a member shaft 18501 having lumen 18505. The diameters of the spring 18406 and pocket washer 18409 can be varied to accommodate the smallest or smaller diameter bone bore using stepped diameter washers 18409 as shown in fig. 185. In the expanded state as shown in FIG. 185, the head 18407 may extend above or a length 18502 from the lip 18410 of the gasket 18409. In the compressed or non-expanded state, head 18407 is positioned within recess 18409A of gasket 18409 or substantially within recess 18409A of gasket 18409.

Fig. 186-191 illustrate some types of spring mechanisms that may be used with the embodiments described herein. Fig. 186 is an isometric view of a bone fixation bevel washer with a separate contact member on the outer diameter of the spring element. Fig. 187 is an isometric view of a bone fixation bevel washer with a separate contact member on an inner diameter spring element arrangement. FIG. 188 is an isometric view of a bone fixation bevel washer with a separate contact member on the outer diameter, the washer having a twisted orientation to assist in rotational control and rotation of the spring element arrangement. Fig. 189 is an isometric view of a bone fixation wave spring element device. Fig. 190 is an isometric view of a bone fixation conical helically wound flat element spring element arrangement. Figure 191 is an isometric view of a bone fixation helically wound circular or elliptical wire element spring device.

Fig. 192 and 193 depict embodiments of the present invention. Graph 192 is similar to graph 140 and graph 193 is similar to graph 165.

FIG. 194 is a graph comparing the load and unload force profiles relative to the distance the device of the present invention is displaced relative to a standard bone screw (non-linear). Wire 19400 is the load of the screw of the present invention during deformation of the deformable portion and wire 19401 is the load after the engagement feature limits the deformation and continues the load. Wire 19402 is the initial unloading of the deformable screw according to the invention. Wire 19403 is the unloading of the deformable screw during the recovery of the deformation of the deformable portion. Dashed line 19404 is the loading and dashed line 19405 is the unloading of a standard non-expandable screw.

Standard screws lose compression force in the range of less than 1 mm where the distance of the compressed substrate is reduced. The deformable screw of the present invention can maintain a compression load that is relaxed beyond a distance or position of 4 millimeters.

195- "208 illustrates another aspect of some embodiments of the invention. 195-208 show some angles at which the slots of the above-described features may be formed in one component. These kerf angles can produce different behavior in deformable portions that employ other similar kerf patterns by varying the cross-sectional shape and area of the features. Different grooving angles may also affect the embodiment by changing the interference, the surface of contact and the direction of the applied load. The following description will capture some of the functions that can be achieved by the different possible notch angle cuts.

FIG. 195 illustrates a cannulated screw or connecting member 19500 similar to the embodiment illustrated in FIGS. 140-142. The member is shown having a partial axial cross-section along surface 19531 and a partial cross-section along surface 19532 relative to longitudinal center axis 19533. Surfaces 19531 intersect undercut 19502, forming pillars 19501. Surface 19532 intersects slot 19502 to form a twist engagement member 19503.

FIG. 196 illustrates a cross-sectional view of a portion of a member 19600 that employs a cannulated central helical expandable section 19610, similar to that illustrated in FIG. 138. Surface 19531 formed by the axial cross-section is the direction of the image, i.e., perpendicular to the view. The strut 1901 is formed by a slot 1902 that is formed through a sidewall 19605 of the member 19600 at an angle that is substantially perpendicular to the longitudinal central axis 19533 (i.e., 90 degrees or perpendicular to the central axis 19533).

FIG. 197 illustrates a cross-sectional view of a portion of a component 19700 employing a hollow central helical expandable section 19710. Surface 19531 formed by the axial cross-section is the direction of the image, i.e., perpendicular to the viewer. Strut 19701 is formed by a slot 1702, the slot 1702 passing through a side wall 19705 of member 19700 at an angle 19734 relative to an orthogonal axis 19736. Angle 19734 may be approximately plus or minus 80 degrees. The line or plane between the outer edge 19735 of the slot 19702 and the inner edge 19737 of the slot 19702 is not parallel to the orthogonal axis 19736. The angle 19734 is shown to be uniform or homogeneous throughout the expansible portion 19710.

Fig. 198 shows a cross-sectional view of a portion of member 19800 employing a hollow central helical expandable section 19810. Surface 19531 formed by the axial cross-section is the direction of the image, i.e., perpendicular to the viewer. Strut 19801 is formed by a cutout 19802 made through side wall 19805 of member 19800 at an angle 19834 relative to orthogonal axis 19836. Angle 19834 may be approximately plus or minus 80 degrees. The line or plane between the outer edge 19835 of the slot 19802 and the inner edge 19837 of the slot 19802 is not parallel to the orthogonal axis 19836. In the present embodiment, angle 19834 is shown as varying along axis 19533. For example, slot 19802 may transition to a different angle 19834, thereby creating slot 19802 in a different plane along axis 1953. This change in angle produces a different or variable pattern of cuts on the outer and/or inner surfaces of member 19800. This is because as the angle 19834 changes, the cross-sectional area changes along the axis 19533. Bending stiffness, rotational response, diameter change (in response to torsional, axial, and bending loads) vary with these non-orthogonal cutting angles.

The angle of the cut may also vary in other planes. Fig. 199-203 is a partial perspective view of a deformable portion of a bone fixation device having a deformable or expandable segment without threads, which in an unexpanded state illustrates a change in cutting angle shown on cross-section 19502 that is approximately at an angle to the angle of the slots of the struts forming the deformable portion. 204-208 are partial perspective views of a deformable portion of a bone fixation device having a deformable or expandable segment without threads, showing the change in chamfer shown in a cross-section perpendicular to the longitudinal central axis of the fixation device in a non-expanded state. The chamfer of the slots forming the twist engagement feature of the device is shown in fig. 199-208.

Fig. 199 and 204 illustrate cross-sectional views of the torsional engagement feature 19903 through the deformable portion of the hollow bone fixation member 19900. The sides of the twist engagement feature 19903 are formed by a cut path 19944 and a cut path 19946 through the side wall 19931 of the member 19900. For clarity, in FIG. 204, cutting paths 19944 and 19946 are shown with lines or planes inserted therein and protruding therefrom. The cutting paths 19944 and 19946 are formed orthogonal to a tangent of the circumference of the member 1960. In other words, the lines or planes 20448 inserted through the cut paths 19944 and 19946 intersect at the longitudinal central axis 20433 of the member 19900.

Fig. 200 and 205 show cross-sectional views of the torsional engagement feature 20003 through the deformable portion of the cannulated bone fixation member 20000. The sides of the twist engagement feature 20003 are formed by cutting paths 20044 and 20046 through the side wall 20031 of the member 20000. For clarity, in fig. 205, cutting paths 20044 and 20046 are shown having lines or planes inserted therein and protruding therefrom. The cutting paths 20044 and 20046 are formed asymmetrically and are formed non-orthogonally with respect to a tangent of the circumference of the member 20000. The asymmetric cutting paths 20044 and 20046, respectively, are formed at different negative angles with respect to a reference line or plane 20548 that radially extends or radiates from the longitudinal central axis 20533 of the member 20000.

Fig. 201 and 206 show cross-sectional views of the twist engagement feature 20103 through the deformable portion of the cannulated bone fixation member 20100. The sides of the twist engagement features 20103 are formed by cut path 20144 and cut path 20146 passing through the side walls 20131 of the members 20100. For clarity, in figure 206, cutting paths 20144 and 20146 are shown having lines or planes inserted therein and protruding therefrom. The cutting paths 20144 and 20146 are symmetrically formed and formed not orthogonal to a tangent of the circumference of the member 20100. The cutting path 20144 is negatively angled relative to a reference line or plane 20648 that radially projects or radiates from the longitudinal central axis 20633 of the member 20100. The cutting path 20146 is formed at a positive angle relative to a reference line or plane 20648, which reference line or plane 20648 projects or radiates radially from a longitudinal central axis 20633 of the member 20100. As shown in fig. 201 and 206, the cutting paths 20144 and 20146 are parallel to each other.

Fig. 202 and 207 illustrate cross-sectional views of the torsional engagement feature 20203 through the deformable portion of the hollow bone fixation member 20200. The sides of twist interface feature 20203 are formed by cut path 20244 and cut path 20246 passing through sidewall 20231 of member 20200. For clarity, in fig. 207, dicing paths 20244 and 20246 are shown with lines or planes inserted therein and protruding therefrom. The cut paths 20244 and 20246 are formed asymmetrically or symmetrically, and are formed so as not to be orthogonal to a tangent of the circumference of the member 20200. The cutting path 20244 is at a negative angle relative to a reference line or plane 20748 that projects or radiates radially from the longitudinal central axis 20733 of the member 20200. The cutting path 20246 is at a positive angle relative to a reference line or plane 20648 that projects or radiates radially from the longitudinal central axis 20633 of the member 20100. As shown in fig. 202 and 207, the cut paths 20244 and 20246 are not parallel to each other. Due to the orientation of the cut paths 20244 and 20246, the ability of the twist engagement feature 20203 to move in its radial direction away from the central axis 20733 is limited.

Fig. 203 and 208 illustrate cross-sectional views of the torsional engagement feature 20303 through the deformable portion of the hollow bone fixation member 20300. The sides of the torsional engagement feature 20303 are formed by a cut path 20344 and a cut path 20346 through the side wall 20331 of the member 20300. For clarity, in fig. 208, the cutting paths 20344 and 20346 are shown with lines or flats inserted therein and projecting therefrom. The cutting paths 20344 and 20346 are formed asymmetrically or symmetrically, and are formed not orthogonally to a tangent of the circumference of the member 20300. The cutting path 20344 is at a positive angle relative to a reference line or plane 20848 that projects or radiates radially from the longitudinal center axis 20833 of the member 20300. The cutting path 20346 is formed at a negative angle relative to a reference line or plane 20748 that is a reference line or plane 20748 that projects or radiates radially from the longitudinal center axis 20833 of the member 20300. As shown in fig. 203 and 208, the cutting paths 20344 and 20346 are not parallel to each other.

For purposes of clarity only, the methods described and illustrated with respect to fig. 209-211 are described as being performed in a progression or sequence of different steps. It is to be understood and within the scope of this disclosure that such steps are performed in an alternating order or sequence and that the embodiments may omit steps shown and/or described in connection with the illustrative methods. Embodiments may include steps not shown or described in connection with the illustrative methods. Illustrative method steps may be combined. For example, one illustrative method may include the steps shown in conjunction with another illustrative method.

Fig. 209 and 210 are flow charts describing the method and process progression for inserting the connecting member of the present invention into bone tissue to facilitate a desired treatment. Expansion begins by inserting a K-wire or guide pin into the desired placement location, e.g., a fracture plane across the bone. Once the lead is placed, a measurement of the desired length of the connecting member can be made using the relative length of the lead and the bone surface. Thereafter, a hollow drill bit is inserted over the K-wire to increase the diameter of the hole and potentially promote a better mechanical fit between the bone and the connecting member. Depending on the type of screw and the desired screw head position, one may sink bone tissue to accommodate the screw head diameter, thereby helping to reduce stress on the bone and/or adjust the height of the exposed head of the screw above the bone tissue (fig. 210).

The connecting member may then be rotated into the bone through the K-wire. The end of the connecting member may have self-cutting and self-tapping features, allowing it to displace bone tissue as it is advanced forwardly through the bone. When the head of the connecting component engages the bone, additional friction due to increased size of the head and/or different pitch of the head and/or the distal portion of the head relative to the connecting member will apply a compressive force to the bone segments across the fracture plane. This force will also be applied to the axial tension characteristics of the screw, effectively lengthening the connecting member and storing potential energy in the axial tension. The member will stretch to a predetermined or designed length. After this length is achieved, continued rotation of the screw member will increase the load or axial tension applied to the tissue by the member. After insertion is complete, the bone will begin to remodel during the healing process, and depending on the stress state of any individual bone cell, the bone growth process will take up or create more bone cells at that location. This process will continue until the bone reaches a stress level acceptable for bone cells. This process may continue with stored axial tension energy that continues to apply force to the bone across the fracture plane, thereby creating the desired therapeutically beneficial pressure that helps aid healing.

FIG. 211 is a flow chart depicting a method and manufacturing process for constructing a joining member in accordance with the present invention. A bar stock is drawn from a metal ingot of appropriate chemical structure (e.g., nitinol) and cold worked to the appropriate diameter and desired physical properties. The next step is to drill a hole in the central lumen and machine the desired threads and external profile of the feature into the tubing. The machining may be standard machining techniques, low temperature machining, EDM (electrical discharge machining), grinding or other techniques known to those skilled in the art.

Fig. 212 is an example of a cutting pattern known in the art.

FIGS. 213, 214, 215, 215A, 216C, 217, and 217A are various illustrative embodiments included herein to further depict and explain the functional aspects of the length and twist control features of the disclosed devices described. These embodiments have been simplified to practice and test in various configurations. The data shown here illustrate the actual collected test data. In addition, the structure has been analyzed using finite element analysis by Dassault Systems, FEA, computer software program ABAQUS and an empirical Nitinol Material database. The results of FEA and empirical testing were merged together, validating the test methods disclosed herein and the FEA results.

Fig. 214 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature in a non-expanded state similar to the embodiment shown in fig. 168.

Fig. 215 is a partial side view of a portion of a cutback pattern of a bone fixation device having a non-threaded helical expandable section with a torsional engagement feature and an axial length limiting feature, in a non-expanded state similar to that shown in fig. 169, having 14 tab functions instead of 19 tab functions. The number of tabs may affect performance characteristics.

Fig. 216 and 217 are partial side views of a nick pattern similar to that shown in fig. 212.

Graph 213 shows data collected during evaluation of the construction of the 0.118 inch diameter shank having a 0.5 inch axial length cutting pattern depicted in graphs 214, 215, 216 and 217. The arrangement is loaded under axial tension until failure. At the same time a torsion load of at most 0.25Nm is also applied. Graph 213 shows the failure points in two separate modes. The first failure mode is the manner in which the opposing portions of the feature fail, unzip or otherwise disengage from one another. After separation of the features, the construction cannot be fully restored because the material has yielded and cannot restore the geometry of the original construction. The second mode is that the structure yields completely from end to end. For clinical purposes, the point of characteristic yield or detachment is a critical point. All four designs withstand loads of about 180N and 0.1 Nm.

Clinically significant differentiation is the ability of the construct to withstand so-called pretension. In the use of bone screws, the screws are typically engaged in cortical bone and tightened to the tip of the bone tissue to ensure that the maximum compression force of the bone segments can exceed 600N. Even though this illustration is only intended to show potential differences, only the inventive construct shown in figure 214 demonstrates the ability to withstand load conditions greater than 600N and still recover therefrom. The greater the range of forces, the greater the margin of safety in various clinical situations. The construction of the invention shown in fig. 215 may be similar to that shown in fig. 214 if designed to have 19 torsional engagement features instead of the 14 engagement features used in this study.

The ability of each of these configurations to return to its original axial dimension or relaxed, lower stress state is not shown here. The configuration shown in fig. 216 and 217 operates on both interfacing surfaces in a wedging principle. This creates a mechanism similar to a taper fit. The greater the force which is used for which principle for engagement, the greater the force required for disengagement. Two other designs, shown in fig. 214 and 215, are designs of the present invention that do not have a wedge mechanism on either side of the feature, thereby resulting in less restoring force.

Fig. 214A, 215A, 216A and 217A depict the configurations shown in fig. 214, 215, 216 and 217 under axial and torsional loading conditions in the first disengagement or failure of their respective features. For the embodiment shown in fig. 214, the point at which the feature yields or fails is indicated at 21402; see fig. 21. 21502 for the embodiment shown in fig. 215; the structure shown in fig. 216 is 21602; 21702 for the construct shown in figure 217; the construct shown for figure 217 is 21702. Fig. 214A shows the detachment at point 21402, which corresponds to point 21301 at 3.5mm 1026N shown in fig. 213. Fig. 215A shows the disengagement of point 21502, which corresponds to point 21302 at 578N at 3.75mm shown in fig. 213. Fig. 216A shows the disengagement of point 21602, which corresponds to point 21304 at 124N, shown in fig. 213, at 2.7 mm. Fig. 217A shows the detachment of point 21702, which corresponds to point 21303 at 285N at 3.1mm shown in fig. 213.

Shaded areas 21401, 21501, 21601, and 21701, shown in fig. 214A, 215A, 216A, and 217A, respectively, represent the amount and distribution of stress that a material experiences due to loading conditions, the darker the color, the higher the stress.

FIGS. 214B, 214C, 216B and 216C illustrate another aspect of the invention. The configurations shown in fig. 214B, 214C, 216B, and 216C are shown in bending or lateral deformation relative to the original unbent central longitudinal axes 21407 and 21607 at the same time. The total displacement 21403 shown in fig. 214B and total displacement 21603 shown in fig. 216B of the structure are shown, with displacement 21603 being greater than displacement 21403. As shown, the gap 21605 on the outer convex edge of the flexure structure shown in FIGS. 216B and 216C is greater than the gap 21405 on the outer convex edge of the flexure structure shown in FIGS. 214B and 214C. In both configurations, the gap 21604 on the concave edge of the configuration shown in fig. 216B and 216C and the gap 21404 on the concave edge of the configuration shown in fig. 214B and 214C are also different. The gap 21406 shown in fig. 214B is completely closed similar to the gap 21604 shown in fig. 216B and 216C, however, similar to the gap 16813 described above and shown in fig. 168B, the gap 21404 is only closed proportionally to the size of the gap 21404, similar to the gap 16811 shown in fig. 168B. As shown in fig. 216, the ability of the geometry to move relative to its adjacent faces allows for a more unobstructed lateral displacement of the construct. These variables can be altered to produce highly flexible or relatively rigid constructs, depending on the design goals of the construct.

Fig. 218, 219, 220, 221, 222, 223, 224 and 225 represent test set-up and data collected in an example where a pattern was cut with an axial length of 0.5 inch, a 4 mm diameter screw with a 0.18 inch diameter shank, and a commercially available device according to astm f543-17 standard specification and a test method for metallic medical bone screws based on ISO 5835, ISO6475 and ISO 9268 are illustrated.

Fig. 218 shows a tension testing device with a screw 21801. Data from the pull test is shown in figure 219. The pulled structures are commercially available Solid screws (Solid) and screws of the invention (ActivOrtho) having the same central cross-section with the same diameter, as shown in fig. 214. The material was (rigid closed cell Polyurethane (PU) foam 1522-03 of Vashon Island, Washington). Graph 220 is a graph depicting the result of pulling a 0.118 inch diameter shank screw to failure, indicated at point 22001, in the center section shown in graph 214.

FIG. 221 is a graph of a compression test block with a screw of the present invention having a shank diameter of 0.118 inches and a deformable center section as shown in FIG. 214. When the distance between the compressed blocks is reduced by a few millimeters, the area 22101 is a restoring force.

FIG. 222 is a graph of the torque to failure of a screw of the present invention having a shank diameter of 0.118 inch with a deformable center section as shown in FIG. 214.

Fig. 223, 224 and 225 represent data set up and collected for the tests of the embodiments described herein, as well as testing methods and test methods for metallic medical bone screws based on ISO 5835, ISO 6475 and ISO 9268 in a four-point bending test according to the ASTM F543-17 standard specification, a commercially available device in the industry. Selecting a rigid closed cell polyurethane foam having a density of 20pcf1522-03, island of wakaw, washington) as an alternative material to the experiment, the blocks were machined to a size of 20 × 20 × 120mm, a full transverse osteotomy was created in the middle of each foam block, the structure was loaded in a four-point bending mode with an upper span of 30mm and a lower span of 90mm, the sample was subjected to displacement control testing at a speed of 1mm/min until an axial load of 200N or an actuator displacement of 3mm was reached, loading was performed to produce a dorsum moment of up to 6Nm, time, load and actuator displacement data were recorded at 20Hz and used to calculate stiffness and peak load/displacement, the sample was maintained at 37 ℃ during the test.

Fig. 223 shows a test device with a load cell 22301 and a test sample 22302, which is detailed in fig. 224. Fig. 224 shows two 0.118 inch diameter 4mm screws 22401 ("active 4.0mm screws") with a deformable center section as shown in fig. 214, which passes through a fracture plane 22403.

For the active 4.0mm screw and 4.0mm solid Cann screw samples of the invention, 2 angled pilot holes of approximately 45 degrees were drilled using a 3.0mm drill bit (for the active 4.0mm screw) and a 2.8mm drill bit (for the 4.0mm solid Cann screw). The two holes intersect laterally only at the midpoint of the block thickness (10 mm). Each inclined hole was countersunk using a 5.5mm counter drill. After the pre-drilling is completed, a cross-cut is made to ensure proper chip alignment. A 4.0mm screw was inserted for movement so as to obtain a screw elongation of 2 mm. This was verified by measuring the length of the screw after insertion.

The implants used were SMA nails with a cross-sectional profile of 2mm by 2mm with a bridge width and leg length of 20 mm. After release from the applicator, the bridge had a closure of 1.5mm and the maximum closure of the lower limb was at most 10.8 mm. In comparison, an eight hole, 2.7mm quarter-tube bone plate and a 2.7 x 22mm self-tapping cortical bone screw were used. For the single nail configuration, holes of 2.5 mm were predrilled using a guide and the nitinol nails contained in the applicator were then inserted into these holes and released. For the double nail configuration, care should be taken to avoid drilling holes in the vertical holes. Rather than drilling 10 millimeters on each side of the osteotomy in a single staple configuration, the drill holes are offset in opposite directions by 5 millimeters for each staple. The plates were implanted by keeping the concentrated plates and composite blocks flush with the bench vise, while 2.0 mm pilot holes were drilled, and screws were inserted. Six screws were placed with two holes open next to the osteotomy. There are a sufficient number of plates and staples so that each plate and staple can only be used once.

The resulting loads are plotted against the displacement for each sample tested in graph 225, where the active 4.0mm screw sample of the invention shows a stiffness 22501 comparable to a solid screw configuration.

The present invention provides fixation devices and fixation devices comprising a helical strut secured between a proximal bone engaging portion and a distal bone engaging portion, the helical strut being formed by a perforation through a sidewall of the device, the helical configuration allowing the device to produce a longitudinal deformation in the range of 1 to 10 millimeters and a tensile force in the range of 10 to 1000 newtons between the distal bone engaging portion and the proximal bone engaging portion when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed, substantially relaxed state.

The present invention provides a device having characteristics similar to a solid screw in that it can withstand axial tension and torque up to the limits of the threadedly engaged component and the bone tissue to which it is to be applied until compressive forces are applied to the tissue as the tissue remodels and resorbs before the bone tissue or screw material yields.

The present invention provides a device having asymmetrical axial and torsional engagement features.

The present invention provides a device having asymmetrical axial and torsional engagement features. One engagement surface may achieve a minimum frictional engagement within a designed distance and then lock or limit further distance.

The present invention provides a device having asymmetrical axial and torsional engagement features. One engagement surface may achieve a minimum frictional engagement over a designed distance and then lock or limit further distance while the other engagement surface does not engage until the designed extension distance is achieved and then increasingly resistive force is applied under corresponding axial force to further extension.

The present invention provides a device having asymmetrical axial and torsional engagement features. One engagement surface may achieve a minimum frictional engagement over a designed distance and then lock or limit further distance while the other engagement surface does not engage until a designed extension distance is achieved and then further extension is achieved by wedging the engagement feature length locking mechanism against a corresponding axial force with increasing resistance.

The present invention provides a device having asymmetrical axial and torsional engagement characteristics and having characteristics similar to a solid screw that may be subjected to axial tension and torque up to the limits of the threadedly engaged component and the bone tissue to which it is applied until compressive forces are applied to the tissue as the tissue remodels and resorbs before the bone tissue or screw material yields.

The present invention provides a device that creates an axial tension between a distal bone engaging portion and a proximal bone engaging portion when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed, substantially relaxed state. The axial tension is in the range of 10 to 1000 newtons.

The present invention provides a device that is able to withstand, resist failure and/or deformation and does not generally yield when a torsional force of 0.1 to 6 newton meters is applied.

The present invention provides a device that, when implanted into two or more bone segments by applying a torque of 0.1 to 6 newton meters, produces an axial tension between the distal and proximal bone engaging portions when the device is transitioned from a longitudinally elongated stressed state to a longitudinally compressed, substantially relaxed state (for example), the force being in the range of 10 to 1000 newtons.

After the bone segments contact each other and the proximal engagement feature applies a load to the bone segments, the load applied to the bone by using a standard compression screw will increase rapidly. The load may easily exceed the holding force of the distal and proximal tissue engaging members. In addition, the amount of remodeling required to address this focal stress is small and/or limited. The present invention is contrary to this effect, as the connecting member of the present invention will continue to change dimensions as the bone remodels, the compressive force generated will last longer and/or for a greater distance of remodeling of the bone tissue.

The load curves of embodiments of the devices disclosed herein exhibit non-linear behavior. Non-linear springs have a non-linear relationship between force and displacement. The graph shows that the force and displacement of the nonlinear spring will have a varying slope. The deformable elastic central portion of the connecting member of the present invention may be stretched when loaded and follow a non-linear profile similar to line 13602. When the spring mechanism reaches its maximum length, the profile of the screw resembles the profile of the wire 13603. This design allows the spring to remain non-linear at all times. Based on the bending of the struts or beams and based on the material properties of the superelastic material, these properties of the springs or deformable portions of the inventive devices disclosed herein produce a force that varies non-linearly with respect to its displacement. The devices and methods of the present invention provide an engagement member that exerts a compressive force on at least two tissue members. By applying a stored axial tensile elastic potential energy that is released by a mechanism that uses beam bending and the material properties of the superelastic material to generate a force that varies non-linearly with displacement.

In certain embodiments of the invention, any of the connection members disclosed herein are used to secure or otherwise fix rods and/or plates to tissue and/or bone. In certain embodiments of the invention, the connecting member employs a locking feature corresponding to a feature on the rod and/or plate to lock or secure a portion of the connecting member, such as a proximal head of the connecting member, for example, within a hole or aperture of the rod and/or plate. In certain embodiments of the invention, the position of the connecting member is not fixed or movable within the rod and/or plate, for example within an aperture or hole of the rod and/or plate. In certain embodiments of the invention, the connecting member and the rod and/or plate are cold welded to one another. In certain embodiments of the invention, a connecting member is used to secure or otherwise fix the compression rod and/or plate to the tissue and/or bone. In certain embodiments of the invention, the engagement members are used to secure or otherwise fix the movable bar and/or plate to tissue and/or bone. In certain embodiments of the invention, a connecting member is employed to secure or otherwise fix the passive rod and/or plate to tissue and/or bone.

In certain embodiments of the invention, any of the connection members disclosed herein are provided with, treated with, or coated with, a substance such as a biologic, an antibiotic, a bone graft, a BMP, a bone cement, a drug, or any other material useful to help promote bone and/or tissue, and combinations thereof. In certain embodiments, a coating of such a substance is applied to all surfaces of the inventive device. In certain embodiments, a coating of such a substance is applied to only the interior surface or only the exterior surface of the inventive device. In certain embodiments, the surface of the devices of the present invention has a surface texture and/or pores formed therein in which the substance or substances are deposited or coated. In certain embodiments of the invention, the coating is a time-release material.

It will be appreciated that while many of the embodiments disclosed above are described as providing compressive forces on a bone segment, all of the devices disclosed herein are also operable to provide customized axial, torsional, bending, radial, shear and compressive forces, and combinations thereof, to a bone segment, depending on the optimization of the cutting slot features employed in the deformable portion of the coupling member.

It will be understood that while the embodiments disclosed herein have been described as engaging two bone segments, all of the devices disclosed herein are also operable to engage more than two bone segments simultaneously.

The above-described embodiments of the present invention provide systems and methods for active orthopedic screw systems. In particular, embodiments of the present invention are configured to provide customized active axial, torsional, bending, radial, shear and/or compressive forces to a plurality of bone segments to promote bone growth. Thus, the active orthopedic screw system of the present invention increases osteogenic stimulation as well as segment stability.

To provide a complete disclosure, U.S. patent application No. 8,048,134 and international application No. PCT/US2015.063472, both of which are related to the applicant, are incorporated herein by reference in their entirety.

While the invention has been described in terms of particular embodiments and applications, those of ordinary skill in the art, in light of this teaching, will recognize that additional embodiments and modifications can be made without departing from the spirit or scope of the invention as claimed. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof. The various functions are not drawn to scale in accordance with standard practice in the industry. The dimensions of the various features may be shown arbitrarily increased or reduced for clarity of discussion. Some devices may omit features shown and/or described in connection with the illustrative devices. Embodiments may include features not shown or described in connection with the illustrative methods. The features of the illustrative devices may be combined. For example, one illustrative embodiment may include features shown in connection with another illustrative embodiment.

172页详细技术资料下载

Active compression device, method of assembly and method of use

相关技术

网友询问留言