阅读说明：本技术 一种界面螺钉 (Interface screw ) 是由 金振华 杨习锋 曾晨光 于 2020-05-28 设计创作，主要内容包括：本发明提供一种界面螺钉,改善现有界面螺钉结构,增加具有多孔的鞘管,从而防止螺钉植入时对韧带的切割力,一种界面螺钉,其特征在于,所述界面螺钉穿过鞘管；所述鞘管包括：鞘底,位于鞘管底部,所述鞘底上设有供所述界面螺钉穿过的通孔；多个叶片,所述叶片与鞘底连接；所述叶片上设有鞘孔和防滑纹,所述鞘孔位于所述叶片远离所述鞘底的上端,所述防滑纹呈锯齿状分布于所述叶片上,所述防滑纹朝远离所述鞘底的方向倾斜。(The invention provides an interface screw, which improves the structure of the existing interface screw, and is additionally provided with a sheath tube with multiple holes, thereby preventing the cutting force on ligaments when the screw is implanted; the sheath includes: the sheath bottom is positioned at the bottom of the sheath tube, and a through hole for the interface screw to pass through is formed in the sheath bottom; a plurality of blades connected to the sheath bottom; the blade is provided with sheath holes and anti-slip lines, the sheath holes are located at the upper end, far away from the sheath bottom, of the blade, the anti-slip lines are distributed on the blade in a zigzag mode, and the anti-slip lines incline towards the direction far away from the sheath bottom.)

1. An interface screw, wherein the interface screw passes through a sheath; the sheath includes:

the sheath bottom is positioned at the bottom of the sheath tube, and a through hole for the interface screw to pass through is formed in the sheath bottom;

a plurality of blades connected to the sheath bottom; the blade is provided with sheath holes and anti-slip lines, the sheath holes are located at the upper end, far away from the sheath bottom, of the blade, the anti-slip lines are distributed on the blade in a zigzag mode, and the anti-slip lines incline towards the direction far away from the sheath bottom.

2. The interface screw of claim 1, wherein the sheath is made of PCL material, or PLGA material, or PGA-TMC material, or PLGA-TMC material.

3. The interface screw according to claim 1, wherein said interface screw is a homopolymer or copolymer of absorbable polyesters such as polylactide, polycaprolactone, polyglycolide, polytrimethylene carbonate, and optionally hydroxyapatite or bioceramic.

4. The interface screw of claim 1 wherein the interface screw is made by an injection molding, forging process.

5. The interface screw of claim 4 wherein the injection molding temperature is above the melting temperature and below the degradation temperature of the raw materials used.

6. The interface screw of claim 4 wherein the forging temperature is above the glass transition temperature of the raw materials used and below the melting temperature of the raw materials used.

7. The interface screw of claim 4, wherein the forging pressure is 5 to 100T, the forging speed is 0.1 to 15m/s, the forging time is 0.1 to 10min, the chassis rotation rate is 0.1 to 100r/min, the cooling temperature after forging is 0 to 50 ℃, and the cooling time is 1 to 30 min.

Technical Field

The invention relates to the field of medical instruments, in particular to an interface screw.

Background

The fixation strength and creep resistance of the interface screw are particularly important because the interface screw is used in ACL (knee cruciate ligament) reconstruction and serves as a fixation ligament during surgery, and the reciprocating motion of the knee joint causes the interface screw to have a continuous tendency to creep outward. However, the fixing strength and creep resistance of the current interface screw are still insufficient.

The interface screw has the following problems: the interface screw is a hollow conical screw, the head part of the interface screw is thinner, and the interface screw is easy to deform or break under the action of torsion force in the screwing-in process; when the interface screw is screwed in again and the knee joint reciprocates, shearing force is generated on the ligament, so that the ligament is easy to generate fatigue failure; the degradation time of the absorbable interface screw is not matched with the bone ingrowth time, so that the bone density is insufficient, and complications are caused after the operation rehabilitation.

Disclosure of Invention

The invention provides an interface screw, which improves the structure of the existing interface screw and is additionally provided with a sheath tube with multiple holes, thereby preventing the cutting force on ligaments when the screw is implanted.

The technical scheme of the interface screw comprises the following steps:

the interface screw passes through the sheath; the sheath includes:

the sheath bottom is positioned at the bottom of the sheath tube, and a through hole for the interface screw to pass through is formed in the sheath bottom;

a plurality of blades connected to the sheath bottom; the blade is provided with sheath holes and anti-slip lines, the sheath holes are located at the upper end, far away from the sheath bottom, of the blade, the anti-slip lines are distributed on the blade in a zigzag mode, and the anti-slip lines incline towards the direction far away from the sheath bottom.

Preferably, the sheath tube is made of PCL material, PLGA material, PGA-TMC material or PLGA-TMC material.

Preferably, the interface screw is a homopolymer or copolymer of absorbable polyester such as polylactide, polycaprolactone, polyglycolide, polytrimethylene carbonate, and the like, and hydroxyapatite or bioceramic is optionally added.

Preferably, the interface screw is manufactured by injection molding and forging processes.

Preferably, the injection molding temperature is above the melting temperature of the raw materials used and below the degradation temperature.

Preferably, the forging temperature should be above the glass transition temperature of the raw materials used and below the melting temperature of the raw materials used.

Preferably, the forging pressure is 5-100T, the forging speed is 0.1-15 m/s, the forging time is 0.1-10 min, the rotation speed of the chassis is 0.1-100 r/min, the cooling temperature after forging is 0-50 ℃, and the cooling time is 1-30 min.

The sheath tube in the invention is provided with the hole-shaped structure, so that the bone tissue can grow into the sheath tube along the sheath wall, and the screw fixation is firmer and is not easy to fall off.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic view of an interface screw.

Detailed Description

The invention provides an interface screw, which improves the structure of the existing interface screw and is additionally provided with a sheath tube with multiple holes, thereby preventing the cutting force on ligaments when the screw is implanted.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the sheath includes:

the sheath bottom 2 is positioned at the bottom of the sheath tube, and a through hole is formed in the sheath bottom 2 and used for allowing the ligament to penetrate out and allowing the interface bone nail to penetrate out;

a plurality of blades 1, the number of which is not limited to four blades shown in the figure, and a sheath bottom 2 connected to the blades 1. Blade 1 is the main part bearing structure of sheath pipe, plays the effect of protection ligament, and the screw thread of interface screw when preventing to implant is to the cutting effect of ligament, and the blade shrink reduces ligament frictional force when the sheath pipe is implanted, struts the blade when interface screw is implanted, and the increase blade is to ligament pressure to increase overall fixation intensity.

Be equipped with sheath hole 3 and anti-skidding line 4 on the blade 1, sheath hole 3 can be located blade 1 and keep away from the upper end of sheath bottom 2, and the bone tissue of being convenient for grows into back set screw to for the degradation of interface screw provides microenvironment

The anti-slip grains 4 are distributed on the blades in a zigzag mode, the anti-slip grains 4 incline towards the direction far away from the sheath bottom 2, so that the sawteeth and the ligaments are small in angle when implanted, friction is reduced, the sawteeth and the ligaments are large in angle after implanted, and the friction is increased.

The sheath needs higher impact strength, so that a PCL material, a PLGA material, a PGA-TMC material or a PLGA-TMC material is adopted, and the PLGA material, such as PLGA8218, is preferred. GA in the PLGA can improve higher impact strength for the material, and LA provides longer degradation time for the material, and PLGA 8218's degradation time is in 12 ~ 18 months, can satisfy the holding time of interface screw high fixation strength promptly, thereby can ensure fast degradation again and make the inorganic salt in the screw of sheath pipe inside contact bone tissue fast, play the effect of guide bone tissue regeneration.

The interface screw needs high rigidity, more than 2 years of degradation time and can guide bone tissue regeneration, so that the PLLA is taken as a main body material, PLA-TMC is added to regulate and control the degradation time, and hydroxyapatite or beta-TCP or a mixture of the hydroxyapatite and the beta-TCP is added to enable the product to have the effect of guiding the bone tissue regeneration.

The interface screw is formed by blending and injection molding of a copolymer of polylactide and trimethylene carbonate and BCP/beta-TCP, and has the function of inducing bone tissue regeneration.

The interface screw adopts a directional orientation process, so that the screw is oriented along the thread direction, the mechanical strength of the interface screw is improved, the friction force applied during screwing-in is reduced, and the friction force applied during screwing-out is improved.

The preparation method of the interface screw comprises the following steps:

firstly, performing injection molding on the blank, calculating the volume of the required raw material and the size of the blank according to the size of the interface screw, and preparing the hollow cylindrical blank through injection molding.

And then, carrying out reducing forging and pressing to prepare the oriented screw, wherein the forging and pressing needs to design and prepare a reducing forging and pressing die, the outer diameter of the upper die is consistent with that of the blank, the size of the lower die is consistent with that of the screw, a stainless steel thimble is arranged in the middle of the whole die, and the shape and the size of the thimble are consistent with those of the central hole of the interface screw. During forging, the blank is placed in a die cavity, and the temperature is raised to be higher than the glass transition temperature of the blank material and lower than the melting temperature of the blank material, so that the blank is in a high-elasticity state; the bottom of the forging equipment is provided with a variable speed turntable, the variable speed turntable is controlled by a program to rotate at a constant speed or at a variable speed in the forging process, the lower die is driven to rotate at a constant speed or at a variable speed, and in the forging process, the blank is subjected to upward shearing force generated by reducing of the die and circumferential shearing force generated by rotation of the lower die, and the upward shearing force and the circumferential shearing force are matched to generate shearing force along the thread direction, so that the blank is oriented along the thread direction.

The material of the interface screw can be homopolymer or copolymer of absorbable polyester such as polylactide, polycaprolactone, polyglycolide, polytrimethylene carbonate and the like, and can also be blend of the homopolymer or copolymer and inorganic material such as hydroxyapatite, biological ceramic and the like.

The injection molding temperature is above the melting temperature of the raw materials and below the degradation temperature, for example, the injection molding can be carried out at 200-230 ℃ by using polylactide.

The forging temperature is higher than the glass transition temperature of the raw materials and lower than the melting temperature of the raw materials, for example, the polylactide is forged at 65-190 ℃.

The forging pressure is 5-100T, preferably 20-60T. The forging speed is 0.1 to 15m/s, preferably 1 to 5 m/s. The forging time is 0.1-10 min, preferably 0.5-5 min. The rotation rate of the chassis is 0.1 to 100r/min, preferably 1 to 30 r/min. The cooling temperature after forging is 0-50 ℃, and preferably 0-25 ℃. Cooling time: 1-30 min, preferably 1-10 min.

The sheath pipe is complex in size, and the direct injection molding difficulty is high by utilizing the traditional injection molding process, so that a simple processing mode for injection molding by utilizing the parameter control and the high polymer material warping deformation principle is researched, and the processing difficulty and the processing time of the sheath pipe are greatly reduced.

The simple processing technology of the sheath tube mainly comprises the following steps:

(1) the front mould is kept at a high temperature (above the glass transition temperature of the material, for example 110 ℃), and the rear mould is in a low-temperature state through cold water circulation, so that different positions of the injection molded part are ensured to be in different states

(2) The sheath tube is of a four-blade structure, and four blades of the sheath tube are pressed into a nearly planar state for injection molding preparation.

(3) The blade faces the back mould and the sheath bottom faces the front mould during injection molding.

(4) After the injection molding is finished, the blades facing the rear mold are rapidly cooled and hardened, the sheath bottom facing the front mold is slowly cooled and still is above the vitrification temperature, the pressure maintaining time is controlled to be less than 5s, the thimble is rapidly used for aligning the bottom of the sheath tube to eject out the sheath tube, and at the moment, the bottom of the sheath tube generates buckling deformation facing the blade direction due to stress, and finally the sheath tube in a three-dimensional shape is obtained.

(5) For making blade warpage angle obtain better control, a manipulator is designed on one side of the injection molding machine, the manipulator is tubulose and easily dismantles, the pipe diameter is unanimous with the outer maximum diameter of sheath pipe that expects to obtain, the manipulator outside even has hot passageway, invariable more than the vitrification temperature of sheath pipe material through thermostatic water circulation control temperature, mould separation back around the injection molding machine, the manipulator removes to the position of tubulose center and sheath pipe center parallel and level fast, the thimble activity is ejecting to the manipulator middle part with the sheath pipe, ejecting in-process, because the hindrance and the temperature effect of sheath pipe wall, make the sheath pipe can very easy deformation to the spatial structure of original establishing.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.