Intramedullary fixation device for femur

Abstract

The application discloses a femoral intramedullary fixation device, which comprises a main nail arranged in the femoral medullary cavity along the femoral axis, a lag screw arranged in the proximal end of the main nail and used for connecting the proximal end of the femur and the broken femoral head, and a stabilizing screw arranged in the proximal end of the main nail and used for connecting the femoral head and arranged non-parallelly with the lag screw. The application can improve the early fixation effect of the femoral intramedullary fixation device, reduce the rotation and movement probability of the lag screw in the femoral neck, and effectively prevent the proximal end of the femur from turning inwards and other adverse effects by arranging the lag screw non-parallelly with the stabilizing screw.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to a femoral intramedullary fixation device. Background Technology

[0002] Intramedullary nailing of the femoral spine is the preferred treatment for intertrochanteric and femoral shaft complications. A typical intramedullary nail consists of a main nail, a lag screw, a locking screw, and a cap. The lag screw is usually in blade or screw form, or a combination of a main and locking screw. Current intramedullary nails have a simple structure but are unstable in vivo. Postoperatively, lag screws often cut out or penetrate the femoral head, easily causing a zigzag effect, requiring a second surgery, and increasing patient suffering. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an intramedullary fixation device for the femoral spine in orthopedics, which enhances early fixation and reduces the likelihood of rotation and movement of the lag screw in the femoral neck. The cross-design of the lag screw and stabilizing screw effectively prevents adverse effects such as varus fracture of the proximal femur.

[0004] An intramedullary fixation device for the femoral spine includes:

[0005] The master nail is used to be placed in the femoral medullary cavity along the femoral axis;

[0006] A lag screw, which passes through the proximal end of the main nail, is used to connect the proximal femur and the fractured femoral head. The lag screw includes a smooth shaft, a threaded portion, and an enlarged portion. The threaded portion and the enlarged portion are respectively connected to both ends of the smooth shaft. The threaded portion is used to connect with the medullary canal wall of the femoral head. The smooth shaft passes through the main nail. The enlarged portion is used to abut against the femoral surface on the outside of the femur and the proximal end of the femur.

[0007] A stabilizing screw, which passes through the proximal end of the master screw, is used to connect to the femoral head and is not parallel to the tension screw.

[0008] As a preferred embodiment of the above-mentioned intramedullary fixation device for femoral bone marrow, the smooth rod portion and the enlarged portion are connected by a frustum structure, wherein the diameter of the frustum structure gradually increases from the smooth rod portion to the enlarged portion.

[0009] As a preferred embodiment of the above-mentioned intramedullary fixation device for femoral bone marrow, the enlarged portion is an enlarged structure formed by obliquely cutting a cylinder with a diameter larger than that of the smooth rod portion, and the obliquely cut cross section formed by the enlarged portion is elliptical.

[0010] As a preferred embodiment of the above-mentioned femoral intramedullary fixation device, the axis of the tension screw is set obliquely upward along the femoral neck, and when the tension screw is implanted into the femur, the oblique section of the enlarged portion is parallel to the bone surface at the insertion position of the tension screw.

[0011] As a preferred embodiment of the aforementioned intramedullary fixation device for the femoral bone marrow, the tension screw has an axially penetrating bone cement hole.

[0012] As a preferred embodiment of the aforementioned intramedullary fixation device for the femoral bone, the threaded portion is a cancellous bone thread.

[0013] As a preferred embodiment of the above-mentioned femoral intramedullary fixation device, it further includes a pressure pin, which is threadedly connected to the main nail along the axial direction of the main nail, and the pressure pin is used to press the tension screw.

[0014] As a preferred embodiment of the aforementioned intramedullary fixation device for the femoral bone marrow, the stabilizing screw includes a head and a screw rod, wherein the screw rod may be a semi-threaded structure or a fully threaded structure.

[0015] As a preferred embodiment of the above-mentioned intramedullary fixation device for femoral bone marrow, it further includes a tail cap, which is threaded to the proximal end of the main nail, and the outer end face of the tail cap is flush with the proximal end face of the main nail.

[0016] As a preferred embodiment of the above-mentioned intramedullary fixation device for femoral bone marrow, the proximal end of the main nail is provided with a first interlocking hole and a second interlocking hole in sequence. The first interlocking hole is used to install the stabilizing screw, and the second interlocking hole is used to install the tension screw. The axis of the first interlocking hole and the second interlocking hole are both inclined upward from the outside of the main nail towards the inside of the main nail.

[0017] The advantages and positive effects of this invention are:

[0018] The femoral intramedullary fixation device provided by this invention has both lag screws and stabilizing screws inserted on the main screw, and the stabilizing screws and lag screws are not parallel. This increases the overall stability of the femoral intramedullary fixation device for fixing femoral fractures, effectively preventing adverse effects such as varus fracture of the proximal femur, and enabling patients to exercise early, thereby recovering limb function earlier. In addition, the lag screw has an enlarged portion that abuts against the bone surface. As the lag screw is inserted, the enlarged portion compresses the bone surface, causing the threaded portion of the lag screw to drive the femoral head to compress the fracture site of the femoral neck, avoiding complications such as nonunion and improving the fracture healing speed. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the intramedullary fixation device for femoral bone marrow provided by the present invention;

[0020] Figure 2 This is a cross-sectional view of the intramedullary fixation device for the femur provided by the present invention;

[0021] Figure 3This is a schematic diagram of the main nail structure provided by the present invention;

[0022] Figure 4 This is a schematic diagram of the tension screw provided by the present invention;

[0023] Figure 5 This is a schematic diagram of the stabilizing screw provided by the present invention.

[0024] Wherein: 1. Main pin; 11. First interlocking hole; 12. Second interlocking hole; 13. Third interlocking hole; 14. First internal thread; 15. Second internal thread;

[0025] 2. Tension screw; 21. Smooth section; 22. Threaded section; 23. Enlarged section; 24. Frustum structure; 231. Beveled section; 25. Bone cement hole

[0026] 3. Stabilizing screw; 31. Head; 32. Screw;

[0027] 4. Pressing rivet; 5. Tail cap; 6. Locking rivet. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figure 1-5 As shown, this embodiment provides a femoral intramedullary fixation device, which includes a main nail 1, a lag screw 2, and a stabilizing screw 3. The main nail 1 is positioned along the femoral axis within the femoral medullary cavity. The lag screw 2 passes through the proximal end of the main nail 1 and connects the proximal femur to the fractured femoral head. The lag screw 2 includes a smooth shaft 21, a threaded portion 22, and an enlarged portion 23. The threaded portion 22 and the enlarged portion 23 are respectively connected to both ends of the smooth shaft 21. The threaded portion 22 connects to the medullary cavity wall of the femoral head. The smooth shaft 21 passes through the main nail 1, and the enlarged portion 23 is positioned outside the femur and abuts against the bone surface of the proximal femur. The stabilizing screw 3 passes through the proximal end of the main nail 1 and connects to the femoral head, and is not parallel to the lag screw 2.

[0031] In this embodiment, both the tension screw 2 and the stabilizing screw 3 are inserted through the main nail 1, and the stabilizing screw 3 and the tension screw 2 are not parallel. This increases the overall stability of the intramedullary fixation device for fixing femoral fractures, effectively preventing adverse effects such as varus of the proximal femur, and enabling patients to exercise early, thereby recovering limb function earlier. In addition, the tension screw 2 has an enlarged portion 23 that abuts against the bone surface. As the tension screw 2 is inserted, the enlarged portion 23 compresses the bone surface, causing the threaded portion 22 of the tension screw 2 to drive the femoral head to compress the fracture site of the femoral neck, avoiding complications such as nonunion and improving the fracture healing speed.

[0032] In this embodiment, such as Figure 4 As shown, the smooth rod portion 21 and the enlarged portion 23 are connected by a frustum structure 24. The diameter of the frustum structure 24 gradually increases from the smooth rod portion 21 to the enlarged portion 23, so that the smooth rod portion 21 and the enlarged portion 23 can achieve a smooth transition. When the femoral head is pulled and compressed, the frustum structure 24 is attached to the bone surface of the femur. The frustum structure 24 can adapt to the situation around the femoral screw insertion position and can effectively compress the bone surface at that location.

[0033] In this embodiment, the enlarged part 23 is an enlarged structure formed by obliquely cutting a cylinder with a diameter larger than that of the smooth rod part 21, and the oblique section 231 formed by obliquely cutting the enlarged part 23 is elliptical.

[0034] The axis of the tension screw 2 is set obliquely upward along the femoral neck. When the tension screw 2 is inserted into the femur, the oblique section 231 of the enlarged part 23 is parallel to the bone surface at the insertion position of the tension screw 2, so as to avoid forming a sharp part in the enlarged part 23 and causing irritation to the soft tissue.

[0035] In this embodiment, the tension screw 2 has a through bone cement hole 25 in the axial direction. When encountering patients with osteoporosis, bone cement can be injected to increase the fixation effect of the tension screw 2. The threaded part 22 has a cancellous bone thread, which can grasp the inner wall of the medullary cavity.

[0036] In this embodiment, such as Figure 5 As shown, the stabilizing screw 3 includes a head 31 and a screw 32. The screw 32 can be a semi-threaded structure or a fully threaded structure. The stabilizing screw 3 intersects the tension screw 2 and is closer to the proximal end of the main screw 1.

[0037] The intramedullary fixation device for the femoral neck also includes a clamping screw 4, which is threaded into the main screw 1 along its axial direction. The clamping screw 4 is used to clamp the lag screw 2. A groove, such as a slotted or Phillips head, is provided on the proximal end face of the clamping screw 4 to facilitate its insertion. The distal end of the clamping screw 4 abuts against the smooth shaft 21 of the lag screw 2, preventing displacement and rotation of the lag screw 2 relative to the main screw 1, and reducing the likelihood of rotation and movement of the lag screw 2 in the femoral neck.

[0038] The femoral intramedullary fixation device also includes a tail cap 5, which is threaded to the proximal end of the main nail 1, and the outer end face of the tail cap 5 is flush with the proximal end face of the main nail 1. The tail cap 5 is designed to prevent soft tissue from growing into the proximal end of the main nail 1, facilitating the removal of the main nail 1. The tail cap 5 is provided with a slot or cross slot for connecting to tools.

[0039] Locking pin 6 connects to the distal end of main pin 1 and is used to lock main pin 1 to the distal femur. Locking pin 6 forms a stable interlock between the proximal and distal femurs.

[0040] like Figure 2 and Figure 3 As shown, the proximal end of the main nail 1 is provided with a first interlocking hole 11 and a second interlocking hole 12. The first interlocking hole 11 is used to install the stabilizing screw 3, and the second interlocking hole 12 is used to install the tension screw 2. The axes of the first interlocking hole 11 and the second interlocking hole 12 are both inclined upwards from the outside of the main nail 1 towards the inside of the main nail 1. The distal end of the main nail 1 is provided with a third interlocking hole 13, which is used to connect the locking nail 6. Optionally, the axis of the third interlocking hole 13 is approximately perpendicular to the main nail 1.

[0041] The main nail 1 has a first internal thread 14 and a second internal thread 15 along its axial direction. The first internal thread 14 is threadedly engaged with the pressure nail 4, and the second internal thread 15 is threadedly engaged with the tail cap 5.

[0042] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A femoral intramedullary fixation device, comprising: The utility model relates to a kind of femur nail and its application, including: Main nail (1) is used to be arranged in femoral medullary cavity along femoral shaft direction; Tension screw (2) is arranged in the proximal end of the main nail (1), for connecting femoral proximal end and broken femoral head, the tension screw (2) includes light rod part (21), threaded portion (22) and bulging portion (23), threaded portion (22) and bulging portion (23) are connected at the both ends of light rod part (21) respectively, threaded portion (22) is used to be connected with the medullary cavity wall of femoral head, light rod part (21) is arranged in the main nail (1), and bulging portion (23) is used to be arranged outside the femur and abut against the femoral surface of femoral proximal end; Stabilizing screw (3) is arranged in the proximal end of the main nail (1), for being connected with the femoral head, and being arranged non-parallel with the tension screw (2);Bulging portion (23) is abutted against bone surface, and as tension screw (2) is implanted, bulging portion (23) is extruded to bone surface, so that threaded portion (22) of tension screw (2) is extruded to the fracture of femoral neck of femoral head; The bulging portion (23) is the bulging structure formed by beveling the cylinder with diameter larger than the diameter of the light rod part (21), and the beveled section (231) formed by beveling the bulging portion (23) is oval-shaped; The axis of the tension screw (2) is arranged obliquely upward along the femoral neck, and when the tension screw (2) is implanted into the femur, the beveled section (231) of the bulging portion (23) is parallel to the bone surface at the position where the tension screw (2) is implanted; Further comprising a compression screw (4) which is axially and threadedly connected in the main nail (1), and the compression screw (4) is used to compress the tension screw (2); The stabilizing screw (3) includes a head (31) and a screw rod (32), and the screw rod (32) is a full-thread structure; The end of the stabilizing screw away from the head (31) is close to the tension screw (2) relative to the head (31).

2. The femoral intramedullary fixation device of Claim 1, wherein: The light rod part (21) and the bulging portion (23) are connected by a frustum structure (24) with gradually increasing diameter from the light rod part (21) to the bulging portion (23).

3. The femoral intramedullary fixation device of Claim 1, wherein: The tension screw (2) is axially provided with a through bone cement hole (25).

4. The femoral intramedullary fixation device of Claim 1, wherein: The threaded portion (22) is cancellous bone thread.

5. The femoral intramedullary fixation device of Claim 1 wherein, Further comprising a tail cap (5) which is threadedly connected with the proximal end of the main nail (1), and the outer end surface of the tail cap (5) is flush with the proximal end surface of the main nail (1).

6. The femoral intramedullary fixation device of Claim 1, wherein: The proximal end of the main nail (1) is sequentially provided with a first interlocking hole (11) and a second interlocking hole (12), the first interlocking hole (11) is used to install the stabilizing screw (3), and the second interlocking hole (12) is used to install the tension screw (2), and the hole axes of the first interlocking hole (11) and the second interlocking hole (12) are both obliquely upward arranged from the outside of the main nail (1) to the inside of the main nail (1).

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