Intramedullary nail for femur

Abstract

The application provides a femoral intramedullary nail and belongs to the technical field of orthopedic implants. The femoral intramedullary nail comprises a main nail, a tension screw assembly and a proximal locking nail, the tension screw assembly is obliquely arranged on the main nail, the tension screw assembly comprises a nail body and a sleeve, one end of the sleeve is sleeved on one end of the nail body, the other end of the nail body is locked in a femoral head, the other end of the sleeve is provided with the proximal locking nail and connected with the main nail through the proximal locking nail, a flange is arranged in the middle of the nail body, and the flange can abut against the end face of one end of the sleeve to prevent the nail body from being pulled out from the other end of the sleeve. The application can improve the fixing effect of the femoral intramedullary nail, prevent the nail from being pulled out, and is beneficial to the early exercise of patients and the early recovery of limb function.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of orthopedic implants, in particular to a femoral intramedullary nail. BACKGROUND

[0002] The femoral intramedullary nail is the preferred treatment for intertrochanteric fracture of femur, and is usually composed of a main nail, a lag screw, a locking screw and a cap. The lag screw is usually in the form of a blade or a screw, or in the form of a sub-mother nail. During the implantation of the lag screw, the intertrochanteric fracture is usually pre-reduced, and then the lag screw is used to pull the broken fracture close, but not too much force, so that the compression position cannot be accurately positioned, thereby failing to compress the fracture site in place. At the same time, the size of the residual crack cannot be controlled, which will have an adverse effect on the healing of the crack, and the callus recovery time is long, causing malunion. For the lag screw mode of strong fixation, the femoral head will displace along the lag screw axis due to the postoperative self-weight compression at the crack site, and the blade tip is prone to be pierced out, so the lag screw penetration is a normal problem. During the postoperative recovery process, the lag screw is withdrawn, which cannot connect and fix the intertrochanteric fracture, the withdrawn lag screw stimulates the soft tissue, affects normal life, and must be reoperated, and the fracture site cannot be compressed in place, which prolongs the healing time of the fracture site and causes malunion, thereby reducing the quality of life of the patient.

[0003] Therefore, there is an urgent need for a femoral intramedullary nail to solve the above problems. SUMMARY

[0004] Therefore, there is an urgent need for a femoral intramedullary nail to solve the above problems.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0006] The femoral intramedullary nail comprises a main nail, a lag screw assembly and a proximal locking screw, the lag screw assembly is obliquely arranged in the main nail;

[0007] The lag screw assembly comprises a shank and a sleeve, one end of the sleeve is sleeved on one end of the shank, the other end of the shank is locked in the femoral head, the other end of the sleeve is provided with a proximal locking screw and connected with the main nail through the proximal locking screw, and a flange is arranged in the middle of the shank, the flange can abut against the end face of one end of the sleeve to prevent the shank from being pulled out of the other end of the sleeve.

[0008] As a preferred solution of the femoral intramedullary nail, the outer surface of the nail body is provided with a plurality of axial sawteeth, the sleeve is provided with a clamping protrusion engaging with the sawteeth, and the clamping protrusion can block the movement of the sawteeth towards the femoral head after engaging with the sawteeth.

[0009] As a preferred solution of the femoral intramedullary nail, the sleeve comprises a sleeve body and a limiting sleeve, the limiting sleeve is tubular and detachably connected with the sleeve body, and the limiting sleeve is cut to form a first elastic sheet, and the free end of the first elastic sheet is provided with the clamping protrusion.

[0010] As a preferred solution of the femoral intramedullary nail, the limiting sleeve is cut to form a second elastic sheet, and the free end of the second elastic sheet is provided with a clamping hook, and the clamping hook is clamped with the inner wall of the sleeve body.

[0011] As a preferred solution of the femoral intramedullary nail, the inner wall of the sleeve body is provided with a stopper, and the clamping hook is clamped with the stopper.

[0012] As a preferred solution of the femoral intramedullary nail, the outer surface of the nail body is provided with at least one first anti-rotation plane in the radial direction, and the sleeve is provided with a second anti-rotation plane abutting with the first anti-rotation plane.

[0013] As a preferred solution of the femoral intramedullary nail, the second anti-rotation plane is arranged on the inner wall of the limiting sleeve.

[0014] As a preferred solution of the femoral intramedullary nail, the lower side of the distal end of the sleeve body is provided with a protruding lip, the connection between the protruding lip and the sleeve body is provided with a locking hole, and the locking hole is locked with the head of the proximal locking nail.

[0015] As a preferred solution of the femoral intramedullary nail, the end face of the other end of the sleeve is arranged non-perpendicularly to the axis of the sleeve, and after the lag screw assembly is implanted into the femur, the end face of the other end of the sleeve is flush with the surface of the corresponding position of the femur.

[0016] As a preferred solution of the femoral intramedullary nail, the proximal locking nail extends obliquely downwards away from the femoral head, and the central axis of the proximal locking nail is coplanar with the central axis of the lag screw assembly and the central axis of the main nail.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The femoral intramedullary nail of the present application connects the tension screw assembly with the main nail and femur through the proximal locking nail, the proximal locking nail has the anti-retreating function, avoids the tension screw assembly from retreating from the femur surface due to the gravity and postoperative pressure effect, and the sleeve of the tension screw assembly is sleeved on the nail body, and the flange arranged on the nail body can abut against one end face of the sleeve, so that the nail body can be prevented from coming out of the sleeve, therefore, the tension screw assembly of the femoral intramedullary nail will not retreat as a whole or in part, the fixing effect of the femoral intramedullary nail as a whole can be improved, and the early exercise of the patient and the early recovery of the limb function are facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The illustrations are given for the purpose of explaining the application and do not constitute an improper limitation to the application. In the drawings:

[0020] Figure 1 It is a structure schematic view of the femoral intramedullary nail in the specific embodiment of the present application;

[0021] Figure 2 It is a structure schematic view of the tension screw assembly in the specific embodiment of the present application;

[0022] Figure 3 It is a structure schematic view of the tension screw assembly in the specific embodiment of the present application; Figure 2

[0023] Figure 4 It is a local enlarged schematic view of the B part in the specific embodiment of the present application; Figure 2

[0024] Figure 5 It is a local enlarged schematic view of the C part in the specific embodiment of the present application; Figure 3

[0025] Figure 6 It is a structure schematic view of the nail body in the specific embodiment of the present application;

[0026] Figure 7 It is a structure schematic view of the sleeve body in the specific embodiment of the present application;

[0027] Figure 8 It is a structure schematic view of the limiting sleeve in the specific embodiment of the present application.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] ​​​1. Main nail; 2. Nail body; 21. Locking part; 211. Flange; 22. Connecting part; 221. Serration; 23. First anti-rotation plane; 3. Sleeve; 31. Sleeve body; 311. Stop block; 32. Limiting kit; 321. First spring; 3211. Locking protrusion; 322. Second spring; 3221. Locking hook; 323. Flanged structure; 324. Second anti-rotation plane; 33. Protruding lip; 34. Locking hole; 4. Proximal locking nail; 5. Distal locking nail; 6. Tail cap. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0031] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 As shown, this embodiment provides a femoral intramedullary nail, which includes a main nail 1, a tension screw assembly, a proximal locking screw 4, a distal locking screw 5, and a tail cap 6. The tension screw assembly is obliquely inserted into the main nail 1; the tension screw assembly includes a nail body 2 and a sleeve 3. One end of the sleeve 3 is fitted onto one end of the nail body 2, and the other end of the nail body 2 is locked inside the femoral head. The other end of the sleeve 3 is provided with a proximal locking screw 4 and is connected to the main nail 1 through the proximal locking screw 4. A flange 211 is provided in the middle of the nail body 2. The flange 211 can abut against the end face of one end of the sleeve 3 to prevent the nail body 2 from coming out of the other end of the sleeve 3.

[0033] In this embodiment, the femoral intramedullary nail connects the tension screw assembly to the main nail 1 and the femur via a proximal locking screw 4. The proximal locking screw 4 has an anti-retraction function, preventing the tension screw assembly from coming off the femoral surface due to gravity and postoperative pressure. Furthermore, the sleeve 3 in the tension screw assembly is fitted onto the nail body 2, and the flange 211 on the nail body 2 can abut against one end face of the sleeve 3, thus preventing the nail body 2 from coming off the sleeve 3. Therefore, the tension screw assembly of the femoral intramedullary nail, whether as a whole or as a part of it, will not come off, which can improve the overall fixation effect of the femoral intramedullary nail and is beneficial for the patient's early exercise and earlier recovery of limb function.

[0034] like Figure 2 , Figure 4 and Figure 6As shown, the outer surface of the nail body 2 is provided with a plurality of sawteeth 221 in the axial direction, the sleeve 3 is provided with clamping protrusions 3211 which are engaged with the sawteeth 221, and after the engagement of the sawteeth 221 and the clamping protrusions 3211, the clamping protrusions 3211 can block the movement of the sawteeth 221 towards the femoral head. Specifically, the sawteeth 221 are in the shape of a right angle, with one side being an oblique side and the other side being a right angle side, and the right angle side is above the oblique side, so that the right angle side can block the clamping protrusions 3211 from sliding obliquely downwards relative to the nail body 2, thereby preventing the overall growth of the lag screw assembly and avoiding the situation that the nail body 2 slides obliquely upwards relative to the sleeve 3 and penetrates out of the femoral head, and after implantation, the lag screw assembly can only be pressurized in one direction, so that the fractured part of the femoral head will not be repeatedly pulled apart, effectively avoiding the phenomena of bone nonunion and malunion caused by poor fixation of the fractured part.

[0035] As shown in the drawings, Figure 6 The nail body 2 includes a locking portion 21 and a connecting portion 22. The locking portion 21 and the connecting portion 22 are coaxially arranged and integrally formed. After implantation, the locking portion 21 extends into the femoral head and is used for locking connection with the femoral head. Generally, the locking portion 21 is in the form of a thread or a blade, which can be selected according to the form of the fracture. The flange 211 is arranged at the edge of the locking portion 21 which is connected with the connecting portion 22. The connecting portion 22 cooperates with the sleeve 3 and is arranged on the main nail 1. The connecting portion 22 is provided with sawteeth 221 which are engaged with the sleeve 3.

[0036] As shown in the drawings, Figures 4-8 In this embodiment, the sleeve 3 includes a sleeve body 31 and a limiting sleeve 32. The limiting sleeve 32 is in the shape of a tube and is detachably connected to the end of the sleeve body 31 which is close to the femoral head. The limiting sleeve 32 is cut to form a first elastic piece 321. The free end of the first elastic piece 321 is provided with a clamping protrusion 3211 which extends into the sleeve body 31 and is engaged with the sawteeth 221 on the proximal locking nail 4. The first elastic piece 321 is cut from the limiting sleeve 32, and then the clamping protrusion 3211 at the free end is clamped with the sleeve body 31, which is simpler and more convenient than directly machining the clamping protrusion 3211 on the sleeve 3, and the machining difficulty is reduced.

[0037] The limiting sleeve 32 is cut to form a second elastic piece 322. The free end of the second elastic piece 322 is provided with a clamping hook 3221 which is clamped with the inner wall of the sleeve body 31. By arranging the clamping hook 3221 on the limiting sleeve 32, the detachable connection between the limiting sleeve 32 and the sleeve body 31 can be achieved.

[0038] The inner wall of the sleeve body 31 is provided with a stop block 311, and the clamping hook 3221 is clamped with the stop block 311, which can prevent the limiting sleeve 32 from coming out of the sleeve body 31.

[0039] The limiting sleeve set 32 further comprises a flange structure 323 capable of abutting against the end face of the proximal end of the sleeve body 31, capable of limiting the position of the limiting sleeve set 32, and through the connection of the flange structure 323 and the hook 3221 of the limiting sleeve set 32 and the sleeve body 31, the limiting sleeve set 32 is fixed on the sleeve body 31, avoiding the instability of the tension screw assembly caused by the position movement of the limiting sleeve set 32.

[0040] In the embodiment, the outer surface of the nail body 2 is provided with two parallel first anti-rotation planes 23 in the radial direction, and the sleeve 3 is provided with second anti-rotation planes 324 abutting against the first anti-rotation planes 23. Specifically, the second anti-rotation planes 324 are arranged on the inner wall of the limiting sleeve set 32, and two second anti-rotation planes 324 are oppositely arranged. According to specific conditions, the number of the first anti-rotation planes 23 and the second anti-rotation planes 324 can be one, three or more than three. Through the arrangement of the first anti-rotation planes 23 and the second anti-rotation planes 324, the relative rotation between the nail body 2 and the sleeve 3 can be avoided, and then the rotation and movement of the femoral neck caused by the nail body 2 can be avoided, which can effectively prevent the varus of the proximal femur.

[0041] As shown in Figure 7 , the lower side of the end face of the distal end of the sleeve body 31 is provided with a convex lip 33, and the connection part of the convex lip 33 and the sleeve body 31 is provided with a locking hole 34, and the locking hole 34 is locked and connected with the head of the proximal locking nail 4. Through the locking effect of the proximal locking nail 4, the sleeve 3 can be prevented from exiting the inside of the femur.

[0042] In the embodiment, as shown in Figure 1 , the end face of the other end of the sleeve 3 is arranged non-perpendicularly to the axis of the sleeve 3, and after the tension screw assembly is implanted into the femur, the end face of the other end of the sleeve 3 is flush with the surface of the corresponding position of the femur, so that the tension screw assembly does not protrude from the surface of the femur and does not irritate the soft tissue.

[0043] The proximal locking nail 4 extends obliquely downward away from the femoral head, and the central axis of the proximal locking nail 4 is coplanar with the central axis of the tension screw assembly and the central axis of the main nail 1. This design can ensure that the proximal locking nail 4, the tension screw assembly and the main nail 1 form a triangular structure, wherein the proximal locking nail 4 and the main nail 1 are connected while being locked with the femur, and through the locking with the cortical bone of the femur, stable fixation of the locking can be achieved, and then the rotation or misplacement of the femoral head caused by the tension screw assembly can be avoided.

[0044] In the embodiment, the distal locking nail 5 is arranged in the distal end of the main nail 1, and the distal nail body 2 fixes the main nail 1 with the femoral shaft.

[0045] The proximal end of the main nail 1 is detachably provided with a tail cap 6, and the existence of the tail cap 6 can prevent the soft tissue from growing into the proximal end of the intramedullary nail, and facilitate the removal of the main nail 1.

[0046] In the implantation process, the main nail 1 can be implanted into the femoral medullary cavity through the pre-set guide needle, the nail body 2 is selected according to the patient's fracture site and the patient's femoral anatomical shape, and the nail body 2 is implanted into the femoral head through the main nail 1; the sleeve body 31 and the limiting sleeve 32 are combined outside the body, then the sleeve 3 is arranged in the main nail 1, and the sleeve 3 is sleeved on the connecting part 22 of the nail body 2, then the proximal end locking nail 4 is used to lock the sleeve 3 and the cortical bone of the femur through the locking hole 34, the sawtooth 221 on the nail body 2 is engaged with the clamping convex 3211 on the limiting sleeve 32, due to the structural form of the sawtooth 221 and the clamping convex 3211, and the nail body 2 and the sleeve 3 can only move in one direction relative to each other, that is, the nail body 2 moves obliquely downward along the sleeve 3, which can prevent the nail body 2 from penetrating out of the femoral head, and the first anti-rotation plane 23 and the second anti-rotation plane 324 between the nail body 2 and the sleeve 3 can be mutually fitted, which can avoid the rotation or movement of the femoral head and other malposition healing. Then, the distal end locking nail 5 is implanted to lock the main nail 1 and the femoral shaft. Finally, the upper tail cap 6 is assembled on the main nail 1 to avoid the soft tissue growing into the inside of the main nail 1 and facilitate the removal operation when the main nail 1 needs to be removed.

[0047] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. Intramedullary nail for a femur, characterized in that: The main nail (1), the tension screw assembly and the proximal locking nail (4), the tension screw assembly is obliquely upwardly arranged in the main nail (1); The tension screw assembly comprises a nail body (2) and a sleeve (3), one end of the sleeve (3) is sleeved on one end of the nail body (2), the other end of the nail body (2) is locked in the femoral head, the other end of the sleeve (3) is provided with a proximal locking nail (4) and is connected with the main nail (1) through the proximal locking nail (4), the middle of the nail body (2) is provided with a flange (211), the flange (211) can abut against the end face of one end of the sleeve (3) to prevent the nail body (2) from being pulled out from the other end of the sleeve (3); The outer surface of the nail body (2) is provided with a plurality of sawteeth (221) along the axial direction, the sleeve (3) is provided with a clamping convex (3211) engaged with the sawteeth (221), after the sawteeth (221) and the clamping convex (3211) are engaged, the clamping convex (3211) can block the movement of the sawteeth (221) towards the femoral head; The sleeve (3) comprises a sleeve body (31) and a limiting sleeve (32), the limiting sleeve (32) is tubular and detachably connected with the sleeve body (31), the limiting sleeve (32) is cut to form a first elastic sheet (321), and the free end of the first elastic sheet (321) is provided with the clamping convex (3211). The limiting sleeve (32) further comprises a flange structure (323) abutting against the end face of the proximal end of the sleeve body (31) to limit the limiting sleeve (32).

2. The femoral intramedullary nail of claim 1, wherein: The limiting sleeve (32) is cut to form a second elastic sheet (322), the free end of the second elastic sheet (322) is provided with a clamping hook (3221), and the clamping hook (3221) is clamped with the inner wall of the sleeve body (31).

3. The femoral intramedullary nail of claim 2, wherein: The inner wall of the sleeve body (31) is provided with a stop block (311), and the clamping hook (3221) is clamped with the stop block (311).

4. The femoral intramedullary nail of claim 1, wherein: The outer surface of the nail body (2) is provided with at least one first anti-rotation plane (23) along the radial direction, and the sleeve (3) is provided with a second anti-rotation plane (324) abutting against the first anti-rotation plane (23).

5. The femoral intramedullary nail of claim 4, characterized in that: The second anti-rotation plane (324) is arranged on the inner wall of the limiting sleeve (32).

6. The femoral intramedullary nail of claim 1, wherein: The lower side of the distal end of the sleeve body (31) is provided with a convex lip (33), the connection between the convex lip (33) and the sleeve body (31) is provided with a locking hole (34), and the locking hole (34) is locked and connected with the head of the proximal locking nail (4).

7. The femoral intramedullary nail of claim 1, wherein: The end face of the other end of the sleeve (3) is arranged non-perpendicularly to the axis of the sleeve (3), and after the tension screw assembly is implanted into the femur, the end face of the other end of the sleeve (3) is flush with the surface of the corresponding position of the femur.

8. The femoral intramedullary nail of claim 1, wherein: The proximal locking nail (4) extends obliquely downward away from the femoral head, and the central axis of the proximal locking nail (4) is coplanar with the central axis of the tension screw assembly and the central axis of the main nail (1).

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