阅读说明：本技术 股骨髓内钉固定系统 (Femoral intramedullary nail fixing system ) 是由 张英泽 张殿英 许书富 张晓永 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种股骨髓内钉固定系统,属于骨科植入物技术领域,所述股骨髓内钉固定系统包括主钉、斜拉力螺钉和横向张力螺钉,主钉上分别设有用于容纳斜拉力螺钉的第一钉孔和用于容纳横向张力螺钉的第二钉孔,斜拉力螺钉上设有用于容纳横向张力螺钉的第三钉孔,横向张力螺钉与第三钉孔间隙配合,第二钉孔设有内螺纹,横向张力螺钉的杆部设有与内螺纹相配合的第一外螺纹。本发明的股骨髓内钉固定系统便于横向张力螺钉与斜拉力螺钉配合且能够防止横向张力螺钉松动甚至退钉。(The invention discloses a femoral intramedullary nail fixing system, which belongs to the technical field of orthopedic implants and comprises a main nail, a diagonal tension screw and a transverse tension screw, wherein the main nail is respectively provided with a first nail hole for accommodating the diagonal tension screw and a second nail hole for accommodating the transverse tension screw, the diagonal tension screw is provided with a third nail hole for accommodating the transverse tension screw, the transverse tension screw is in clearance fit with the third nail hole, the second nail hole is provided with an internal thread, and the rod part of the transverse tension screw is provided with a first external thread matched with the internal thread. The femoral intramedullary nail fixing system is convenient for the cooperation of the transverse tension screw and the inclined tension screw and can prevent the transverse tension screw from loosening and even withdrawing the nail.)

1. The utility model provides a nail fixing system in femoral bone marrow, its characterized in that, includes main nail, oblique tension screw and horizontal tension screw, be equipped with respectively on the main nail and be used for holding the first nail hole of oblique tension screw and be used for holding the second nail hole of horizontal tension screw, be equipped with on the oblique tension screw and be used for holding the third nail hole of horizontal tension screw, horizontal tension screw with third nail hole clearance fit, the second nail hole is equipped with the internal thread, the pole portion of horizontal tension screw be equipped with the first external screw thread of internal thread matched with.

2. The femoral intramedullary nail fixation system of claim 1, wherein the internal thread is located in a middle portion of the second nail hole, and both ends of the second nail hole are smooth holes.

3. The femoral intramedullary nail fixation system of claim 2, wherein the diameter of the unthreaded hole is larger than the diameter of the internal threads.

4. The intramedullary nail fixation system of claim 1, wherein the head of the lateral tension screw is provided with a second external thread, the second external thread being a cancellous screw thread, the first external thread being a locking thread, wherein:

the pitch of the first external thread is equal to the pitch of the second external thread;

or the pitch of the first external thread is smaller than that of the second external thread;

or the pitch of the first external thread close to the head of the transverse tension screw is equal to that of the second external thread, and the pitch of the first external thread gradually decreases from the head to the tail of the transverse tension screw.

5. The femoral intramedullary nail fixation system of claim 1, wherein the shaft of the lateral tension screw comprises a first shaft portion at a tail portion and a second shaft portion at a head portion, the first shaft portion having a diameter greater than a diameter of the second shaft portion, the first external thread being located on the first shaft portion.

6. The femoral intramedullary nail fixing system according to any one of claims 1 to 5, wherein an axial through hole communicating the first nail hole and the second nail hole is formed in the main nail, a vertical first through hole is formed in a rod portion of the diagonal tension screw located in the first nail hole, a vertical second through hole is formed in a rod portion of the transverse tension screw located in the second nail hole, and fixing rods are inserted into the axial through hole, the first through hole and the second through hole.

7. The femoral intramedullary nail fixation system of claim 6, wherein the second through hole is an oblong hole;

and/or the aperture of the axial through hole is larger than the diameter of the fixed rod, and the diameter of the first through hole is equal to the diameter of the fixed rod.

8. The femur intramedullary nail fixing system according to claim 6, further comprising a lock cap, wherein a threaded hole communicating with the second nail hole is formed in a tail end face of the main nail, the lock cap is in threaded connection with the threaded hole, and the lock cap can be tightly abutted against the fixing rod.

9. The intramedullary nail fixation system of claim 8, wherein a fixation washer is disposed between the locking cap and the fixation rod;

and/or the third nail hole is a long round hole.

10. The femoral intramedullary nail fixing system according to any one of claims 1 to 5, wherein the oblique tension screw comprises a nail body and a tail cap at the tail end of the nail body, the diameter of the tail cap is larger than that of the nail body, a first nail hole in the main nail for mounting the oblique tension screw is provided with a step matched with the end face of the tail cap, and the diameter direction of the step does not exceed the center line of the first nail hole.

Technical Field

The invention relates to the technical field of orthopedic implants, in particular to a femoral intramedullary nail fixing system.

Background

The proximal femoral fracture surgery generally adopts the PFBN (proximal femoral bionic intramedullary nail system) intramedullary nail technique to fix the fractured end, as shown in fig. 1, the technique includes a main nail 1 ', a diagonal tension screw 2 ' (diagonal nail) passing through the upper part of the main nail 1 ', and a transverse tension screw 3 ' (transverse nail) passing through the top of the main nail 1 ' and the diagonal tension screw 2 ', the main nail 1 ' is placed in the femoral bone marrow cavity, the fractured end is driven in through the transverse tension screw 3 ' and the diagonal tension screw 2 ', a triangular support structure is formed after interlocking, and the stability of the fractured end is maintained.

In this triangular support structure, the main nail is fixed in the femoral medullary cavity and is sufficiently stabilized by respective interlocking screws passing through the shaft portion thereof. After the diagonal tension screw penetrates through the inclined nail hole at the upper part of the main nail, the diagonal tension screw can only move back and forth or rotate circumferentially on the axis in the direction of the inclined nail hole of the main nail; after the transverse tension screw passes through the screw hole at the top of the main screw and the cross-connecting hole at the rod part of the diagonal tension screw, the transverse tension screw can be kept stable. The transverse tension screw is used for fixing the main screw and the inclined tension screw, and the self stability of the transverse tension screw is pressed by the tail cap matched with the main screw.

PFBN's triangular supports stable in structure relies on the tail cap of main nail upper end to compress tightly the horizontal tension screw of near-end, because tail cap and horizontal tension screw are rigid structure, and the two contacts for point (approximate line) contact during the cooperation, even screw up the tail cap in the art, the postoperative also causes the not hard up of tail cap very easily, and horizontal tension screw is not hard up or even moves back the nail, and then influences whole triangular supports's stability.

Disclosure of Invention

The invention aims to solve the technical problem of providing a femoral intramedullary nail fixing system which is convenient for matching a transverse tension screw and a diagonal tension screw and prevents the transverse tension screw from loosening and even withdrawing the nail.

In order to solve the technical problems, the invention provides the following technical scheme:

the utility model provides a nail fixing system in femoral bone marrow, includes main nail, oblique tension screw and horizontal tension screw, be equipped with respectively on the main nail and be used for holding the first nail hole of oblique tension screw with be used for holding the second nail hole of horizontal tension screw, be equipped with on the oblique tension screw and be used for holding the third nail hole of horizontal tension screw, horizontal tension screw with third nail hole clearance fit, the second nail hole is equipped with the internal thread, the pole portion of horizontal tension screw be equipped with the first external screw thread of internal thread matched with.

Furthermore, the internal thread is located the middle part in second nail hole, the both ends in second nail hole are the unthreaded hole.

Further, the diameter of the unthreaded hole is larger than the diameter of the internal thread.

Further, the head of the transverse tension screw is provided with a second external thread, the second external thread is a cancellous bone thread, the first external thread is a locking thread, wherein:

the pitch of the first external thread is equal to the pitch of the second external thread;

or the pitch of the first external thread is smaller than that of the second external thread;

or the pitch of the first external thread close to the head of the transverse tension screw is equal to that of the second external thread, and the pitch of the first external thread gradually decreases from the head to the tail of the transverse tension screw.

Furthermore, the rod part of the transverse tension screw comprises a first rod part located at the tail part and a second rod part located at the head part, the diameter of the first rod part is larger than that of the second rod part, and the first external thread is located on the first rod part.

Furthermore, an axial connecting through hole communicated with the first nail hole and the second nail hole is formed in the main nail, a rod part in the first nail hole is provided with a vertical first through hole, a rod part in the second nail hole is provided with a vertical second through hole, and a fixing rod penetrates through the axial connecting through hole, the first through hole and the second through hole.

Further, the second through hole is a long round hole;

and/or the aperture of the axial through hole is larger than the diameter of the fixed rod, and the diameter of the first through hole is equal to the diameter of the fixed rod.

Furthermore, the femoral intramedullary nail fixing system further comprises a lock cap, a threaded hole communicated with the second nail hole is formed in the end face of the tail of the main nail, the lock cap is in threaded connection with the threaded hole, and the lock cap can be tightly abutted to the fixing rod.

Further, a fixing gasket is arranged between the lock cap and the fixing rod;

and/or the third nail hole is a long round hole.

Furthermore, oblique tension screw includes the nail body and is located the tail cap of nail body tail end, and the diameter of this tail cap is greater than the diameter of the nail body, the first nail hole that is used for installing oblique tension screw on the main nail be equipped with the terminal surface matched with step of tail cap, the diametric (al) of step is no longer than the central line in first nail hole.

The invention has the following beneficial effects:

the femoral intramedullary nail fixing system comprises a main nail, a diagonal tension screw and a transverse tension screw, wherein the diagonal tension screw is provided with a third nail hole for accommodating the transverse tension screw, and the transverse tension screw is in clearance fit with the third nail hole, so that the transverse tension screw is convenient to be matched with the diagonal tension screw, and the force distribution is more balanced; the second nail hole is provided with the internal thread, and the pole portion of horizontal tension screw is equipped with the first external screw thread with internal thread matched with, can make the cooperation of horizontal tension screw and main nail inseparabler, realizes the auto-lock with main nail, prevents that horizontal tension screw is not hard up even moves back the nail.

Drawings

FIG. 1 is a schematic structural diagram of a proximal femoral biomimetic intramedullary nail system in the prior art, wherein an enlarged view of a part I is additionally shown;

FIG. 2 is a schematic diagram of the overall structure of one embodiment of the femoral intramedullary nail fixation system of the present invention;

FIG. 3 is a schematic view of the overall structure of another embodiment of the femoral intramedullary nail fixing system of the present invention;

fig. 4 is an overall structural view of still another embodiment of the femoral intramedullary nail fixing system of the present invention, in which an enlarged structural view of a second nail hole is additionally shown;

fig. 5 is a schematic structural view of an initial state of the femoral intramedullary nail fixing system of the present invention in use, in which an enlarged structural view at a fixing rod is additionally shown;

fig. 6 is a schematic structural view of the femoral intramedullary nail fixing system of the present invention in a changed state in use, in which an enlarged structural view at the fixing rod is additionally shown;

FIG. 7 is a schematic diagram of a transverse tension screw in the femoral intramedullary nail fixation system of the present invention;

fig. 8 is a schematic structural view of a locking cap in the femoral intramedullary nail fixing system of the present invention, in which (a) is a front view and (b) is a perspective view;

FIG. 9 is a schematic diagram of three different thread pitches of a lateral tension screw in the intramedullary nail fixation system of the present invention;

fig. 10 is a schematic structural view of a diagonal tension screw in the femoral intramedullary nail fixation system according to the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

The invention provides a femoral intramedullary nail fixing system, which comprises a main nail 1, a diagonal tension screw 2 and a transverse tension screw 3, wherein the main nail 1 is respectively provided with a first nail hole 11 for accommodating the diagonal tension screw 2 and a second nail hole 12 for accommodating the transverse tension screw 3, the diagonal tension screw 2 is provided with a third nail hole 21 for accommodating the transverse tension screw 3, the transverse tension screw 3 is in clearance fit with the third nail hole 21, the second nail hole 12 is provided with an internal thread 121, and the rod part of the transverse tension screw 3 is provided with a first external thread 32 matched with the internal thread 121.

When the device is used, firstly, a surgical tool can be used for holding the main nail 1 and implanting the processed femoral medullary cavity, then, the tool is used for holding the diagonal tension screw 2 to penetrate through the first nail hole 11 which is arranged on the main nail 1 and used for installing the diagonal tension screw 2, then, the tool is used for holding the transverse tension screw 3 and screwing the transverse tension screw 3 into the second nail hole 12 which is arranged on the main nail 1 and used for containing the transverse tension screw 3 and penetrates through the third nail hole 21 on the diagonal tension screw 2, and the implantation is completed.

The femoral intramedullary nail fixing system comprises a main nail 1, a diagonal tension screw 2 and a transverse tension screw 3, wherein the diagonal tension screw 2 is provided with a third nail hole 21 for accommodating the transverse tension screw 3, and the transverse tension screw 3 is in clearance fit with the third nail hole 21, so that the transverse tension screw 3 is convenient to be matched with the diagonal tension screw 2, and the force distribution is more balanced; the second nail hole 12 is provided with an internal thread 121, the rod part of the transverse tension screw 3 is provided with a first external thread 32 matched with the internal thread 121, so that the transverse tension screw 3 is matched with the main nail 1 more tightly, self-locking with the main nail 1 is realized, and the transverse tension screw 3 is prevented from loosening and even retreating. The invention is mainly suitable for intramedullary fixation of proximal femur fracture in surgical operation.

As shown in fig. 2-4, the internal thread 121 is preferably located in the middle of the second nail hole 12, and the two ends of the second nail hole 12 are provided with unthreaded holes 122 and 122', respectively. The diameter of the light holes 122, 122' is preferably larger than the diameter of the internal thread 121, and the light hole 122 at the left end of the illustrated embodiment has a larger diameter than the internal thread 121 at the middle part, and can serve as a guide when the lateral tension screw 3 is implanted; in the embodiment shown in the figure, the diameter of the right unthreaded hole 122' is larger than that of the middle internal thread 121, so that when the transverse tension screw 3 is taken out after fracture healing, the shaft part of the transverse tension screw 3 can be prevented from being deformed due to stress, and the position of the second external thread 33 of the head part of the transverse tension screw 3 can be prevented from interfering with the inner port of the second nail hole 12 of the main nail 1 when the transverse tension screw 3 is taken out.

As shown in fig. 7 and 9, the head of the lateral tension screw 3 may be provided with a second external thread 33, the second external thread 33 being a cancellous bone thread, the first external thread 32 being a locking thread, and the pitch of the first external thread 32 and the pitch of the second external thread 33 may be designed as follows:

structural form 1: the pitch P of the first external thread 32 is equal to the pitch P of the second external thread 33 (as shown in fig. 9 (a));

structural form 2: the pitch P-L of the first external thread 32 is smaller than the pitch P of the second external thread 33 (as shown in (b) of FIG. 9), so that when the lateral tension screw 3 is implanted, the second external thread 33 advances faster than the first external thread 32, and the position of the fracture line M of the femoral neck can be pressed during screwing;

structural form 3: the screw pitch P that first external screw thread 32 is close to horizontal tension screw 3 head equals the screw pitch P of second external screw thread 33, the screw pitch of first external screw thread 32 reduces along the head to the afterbody of horizontal tension screw 3 gradually (as shown in (c) in fig. 9), like this along with the screw in of horizontal tension screw 3, can pressurize fracture line M position of femoral neck, simultaneously, because the screw pitch that is used for holding horizontal tension screw 3 second nail hole 12 on the main nail 1 is unchangeable, in the in-process that first external screw thread 32 was screwed, because of the pressurization between the screw pitch, make first external screw thread 32 and main nail 1 second nail hole 12 complex inseparabler, realize superstrong auto-lock.

As shown in fig. 7, the transverse tension screw 3 can be designed for different diameters (diameter-variable structure), the rod part of the transverse tension screw 3 comprises a first rod part 34 at the tail part (left end in the figure) and a second rod part 35 at the head part (right end in the figure), the diameter of the first rod part 34 is larger than that of the second rod part 35, the first external thread 32 is positioned on the first rod part 34, the second external thread 33 is positioned on the second rod part 35, and the first rod part 34 has a larger diameter, so that the transverse tension screw 3 can be prevented from being broken in use as the stress concentration of the product is mainly the transverse tension screw 3; the second rod part 35 is matched with the third nail hole 21 of the diagonal tension screw 2, the diameter of the second rod part 35 is small, the diameter of the third nail hole 21 matched with the second rod part can be reduced, and the diagonal tension screw 2 is prevented from being broken due to the fact that the third nail hole 21 is too thin. Therefore, the present embodiment can preferably avoid the transverse tension screws 3 and the diagonal tension screws 2 from being broken. The third nail hole 21 is preferably an oblong hole, which allows the lateral tension screw 3 to be moved slightly in the third nail hole 21.

As shown in fig. 3 and 7, the tail of the transverse tension screw 3 may be provided with a tail cap 36 for limiting the depth, so that during the process of screwing the transverse tension screw 3 into the second nail hole 12 of the main nail 1, the tail cap 36 of the tail is always positioned outside the free bone 5 along with the screwing of the transverse tension screw 3, and the free bone 5 outside the femur can be pressurized to pull the free bone 5 towards the femur.

As shown in fig. 2-3, the main nail 1 may be provided with an axial through hole 14 communicating the first nail hole 11 and the second nail hole 12, the rod portion of the oblique tension screw 2 located in the first nail hole 11 is provided with a vertical first through hole 22, the rod portion of the lateral tension screw 3 located in the second nail hole 12 is provided with a vertical second through hole 31, the axial through hole 14, the first through hole 22 and the second through hole 31 are penetrated with the fixing rod 4, the fixing rod 4 penetrates the second through hole 31 of the rod portion of the lateral tension screw 3 to prevent circumferential rotation thereof, compared with the prior art, since the fixing rod 4 sequentially penetrates the second through hole 31 of the lateral tension screw 3, the axial through hole 14 of the main nail 1 and the first through hole 22 of the oblique tension screw 2, the three can be firmly fixed together, the firmness of the whole system is improved, the complete locking of the femoral intramedullary nail fixing system is realized, and the lateral tension screw 3 can be in a locked state, prevent that horizontal tension screw 3 axial back-and-forth movement from preventing that horizontal tension screw 3 is not hard up or even moves back the nail. The second through hole 31 is preferably an oblong hole, so that the transverse tension screw 3 can be moved axially back and forth after the fixing rod 4 has been inserted into the second through hole 31 of the transverse tension screw 3.

The inventor finds that the main nail 1 is obviously stronger than the transverse tension screw 3 because the inclined tension screw 2 is supported by the main nail and the transverse tension screw 3, and the pressure distribution from the femoral head is easily uneven due to the influence of the angle of the inclined tension screw 2 and the matching mode with the triangular area, so that the transverse tension screw 3 is broken. To solve this problem, the present invention may adopt the following structural form:

as shown in fig. 2 to 6, in order to prevent the transverse tension screw 3 from being broken by the full pressure, the diameter of the axial through hole 14 is preferably larger than the diameter of the fixing rod 4, and the diameter of the first through hole 22 is equal to the diameter of the fixing rod 4. In the embodiment shown in the figures, after installation, in the initial state, the fixing rod 4 has a clearance of about 2 DeltaL (as shown in fig. 5, namely, a single-sided DeltaL) with the aperture of the axial through hole 14 in the main nail 1, when the femoral head transmits the pressure F to the intramedullary nail fixing system after operation, the inclined tension screw 2 is forced to retreat and transmits the pressure to the rod part of the transverse tension screw 3 through the position of the third nail hole 21, the rod part of the transverse tension screw 3 is forced to bend downwards, meanwhile, the inclined tension screw 2 retreats along the axial direction, when the transverse tension screw 3 is bent to a certain degree, the transverse distance of the backward movement of the diagonal tension screw 2 reaches delta L, at this time, the fixing rod 4 is tightly attached to the outer side wall of the axial through hole 14 in the main nail 1 (as shown in fig. 6, the distance is 0), the diagonal tension screw 2 is stopped from continuing to move backward, the diagonal tension screw 2 shares a part of the pressure transmitted by the femoral head, and the transverse tension screw 3 is prevented from being broken due to the bearing of the whole pressure.

As shown in fig. 2 and 8, in order to lock the fixing rod 4, the femoral intramedullary nail fixing system may further include a locking cap 13, a threaded hole 15 communicating with the second nail hole 12 is formed in an end face of the tail of the main nail 1, the locking cap 13 is screwed into the threaded hole 15, and the locking cap 13 can be abutted against the fixing rod 4.

Preferably, the middle of the locking cap 13 may be provided with a threaded section 131 matched with the threaded hole 15, so that the locking cap 13 is screwed into the threaded hole 15 through the threaded section 131 and is locked with the threaded hole 15; the lower portion of the locking cap 13 may be a polished rod 132, which facilitates quick guiding of the locking cap 13 into the threaded hole 15.

At this time, the implantation process of the femoral intramedullary nail fixation system of the present invention may be referred to as follows:

when in use, firstly, a main nail 1 can be held by using a surgical tool and implanted into a treated femoral medullary cavity, then a diagonal tension screw 2 is held by using the tool and passes through a first nail hole 11 on the main nail 1 for installing the diagonal tension screw 2, the diagonal tension screw 2 is adjusted to ensure that a first through hole 22 at the rod part of the diagonal tension screw 2 is butted with an axial through hole 14 in the main nail 1, then a transverse tension screw 3 is held by using the tool and screwed into a second nail hole 12 on the main nail 1 for accommodating the transverse tension screw 3 and passes through a third nail hole 21 on the diagonal tension screw 2, the transverse tension screw 3 is adjusted to ensure that a second through hole 31 at the rod part of the transverse tension screw 3 is butted with the axial through hole 14 in the main nail 1, then a fixing rod 4 is held by using the tool and sequentially passes through the second through hole 31, the axial through hole 14 and the first through hole 22, and finally a locking cap 13 is held by using the tool and installed at the tail part of the main nail 1, the implantation is complete.

Can be provided with the fixing shim 41 between lock nut 13 and the dead lever 4, compare in prior art, lock nut 13 and fixing shim 41 are face contact, can be at the in-process of lock nut 13 locking, and fixing shim 41 plays the effect of locking shim, prevents that lock nut 13 is not hard up.

Further, in order to facilitate installation of the fixing washer 41, the fixing washer 41 and the fixing rod 4 are preferably of an integral structure (i.e. the fixing washer 41 is fixed at the upper end of the fixing rod 4), the bottom of the fixing washer 41 may be of different shapes such as a plane, an inclined plane or a groove, and may be pressed against the first external thread 32 of the rod portion of the transverse tension screw 3 (as shown in fig. 3) or may be non-contact (as shown in fig. 2), because the transverse tension screw 3 is screwed into the second nail hole 12 of the main nail 1 through the first external thread 32 of the rod portion, and the fixing rod 4 passes through the second through hole 31 of the transverse tension screw 3, so that the transverse tension screw 3 cannot rotate circumferentially, that is, locking of the transverse tension screw 3 is achieved.

As shown in fig. 10, the oblique tension screw 2 may include a screw body 23 and a tail cap 24 at the tail end of the screw body 23, the diameter of the tail cap 24 is greater than that of the screw body 23, a step (not shown) matched with the end surface of the tail cap 24 is arranged in the first screw hole 11 for installing the oblique tension screw 2 on the main screw 1, so that the end surface of the tail cap 24 abuts against the step and is in surface contact, which is firmer than point contact, at this time, the oblique tension screw 2 is continuously screwed by an instrument, the femoral head is tensioned by a threaded section 25 at the head (right end in the figure) of the oblique tension screw 2, the fracture line M is pressurized, and when the instrument is removed, the oblique tension screw 2 does not rotate reversely, so that there is no risk of re-opening the fracture line M. The inclined tension screws 2 are preferably in clearance fit with the first nail holes 11 in the main nail 1 for accommodating the inclined tension screws 2, and the pressure of the inclined tension screws 2 on the transverse tension screws 3 can be adjusted, so that the force distribution is more balanced. The diameter direction of the step is not more than the central line of the first nail hole 11, so that the step is prevented from being arranged to cause the first improvement reduction of the thickness of the main nail 1 corresponding to the central line of the first nail hole 11, and the strength of the main nail 1 is effectively ensured.

The intramedullary nail operation requires that the tail cap end of the diagonal tension screw is flush with the outer side of the femoral shaft, and if the oblique tension screw penetrates into the femoral shaft, the oblique tension screw grows into the bone in the fracture healing process, so that the screw is difficult to take; if it leaks out of the femoral shaft, its outer slope may damage the collateral muscles. To avoid this problem, as shown in fig. 2 and 10, the tail end of the tail cap 24 of the diagonal tension screw 2 is preferably an inclined surface 241, and an included angle α between the inclined surface 241 and the axial line of the diagonal tension screw 2 is preferably 30 to 70 degrees, and specifically may be 30 degrees, 45 degrees, 50 degrees, 70 degrees, or the like, so as to match the inclination angle of the femoral shaft.

In order to select the tail cap 24 with a suitable length according to the diameter of the femoral shaft of different people and enable the tail cap 24 to be flush with the outer side of the femoral shaft, the tail cap 24 of the oblique tension screw 2 can be designed as a separate tail cap, and can be detachably connected to the screw body 23 of the oblique tension screw 2 through the fixing screw 26, and the specific structure of the fixing screw 26 for fixing the tail cap 24 on the screw body 23 can adopt a conventional structure in the field, and is not described in detail herein.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.