Novel proximal femur intramedullary nail system

Abstract

The invention discloses a novel proximal femur intramedullary nail system which is characterized by comprising a main nail (comprising a tail cap), a head and neck nail, an anti-introversion supporting nail and a far-end locking nail, a far-end locking hole is formed in the far end of the main nail, the far-end locking nail is installed in the far-end locking hole, a head and neck nail hole, an anti-introversion supporting nail hole and a far-end locking hole are sequentially formed in the proximal end of the main nail from near to far, and the head and neck nail hole is communicated with the far-end locking hole. A head and neck nail, an anti-introversion supporting nail and a far-end lock nail are installed in the main nail, the head of the anti-introversion supporting nail is located in the head and neck nail sliding groove after the anti-introversion supporting nail penetrates out of the anti-introversion supporting nail hole, and the main nail, the head and neck nail and the anti-introversion supporting nail form triangular stable support. According to the design, a single nail (head and neck nail) bearing mode of a traditional proximal femur intramedullary nail is converted into a triangular support combined bearing mode, and the anti-introversion supporting nail is tightly attached to the inner side wall of the proximal femur, so that bone blocks are prevented from sliding outwards, and the femoral head is effectively prevented from collapsing inwards and downwards (namely introversion deformity) during load bearing.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a novel proximal femoral intramedullary nail system. Background Technology

[0002] With the accelerating aging of society, the incidence of intertrochanteric fractures of the femur has increased significantly. This type of fracture often occurs in the elderly population with multiple underlying diseases. If not treated properly, the disability and mortality rates are extremely high, hence it is often referred to as "the last fracture of one's life," highlighting its enormous treatment challenges and dangers.

[0003] Currently, intramedullary nailing of the proximal femur has become the mainstream surgical procedure for treating intertrochanteric fractures of the femur. Compared with extramedullary fixation systems, intramedullary fixation devices, represented by Gamma Nail, Intertan intramedullary nail, and proximal femoral antirotation nail (PFNA), have gained widespread clinical acceptance and achieved good treatment results due to their advantages such as central fixation, short lever arm, and superior biomechanical properties.

[0004] However, existing intramedullary nail systems still face a series of serious complication challenges in clinical application, which severely affect patients' postoperative rehabilitation and functional prognosis. Common complications mainly include: internal fixation device fracture, including main nail fracture and head-neck screw (lag screw) fracture; and coxa vara, which is one of the key complications leading to surgical failure. The occurrence of coxa vara significantly alters the biomechanical environment of the head-neck screw within the femoral head, leading to stress concentration at the screw tip, which can easily result in head-neck screw extrusion or lower limb shortening leading to limping.

[0005] Therefore, there is an urgent need in this field for a new type of proximal femoral intramedullary nail system that can not only achieve reliable fixation of fractures, but also actively and effectively prevent the occurrence of coxa vara deformity from a mechanical mechanism perspective, thereby fundamentally improving the success rate of surgery and the long-term efficacy for patients. Summary of the Invention

[0006] To address the occurrence of coxa vara deformity in the prior art, one of the objectives of this application is to provide a novel proximal femoral intramedullary nail system.

[0007] To solve the aforementioned technical problems, this application adopts the following technical solution: A novel proximal femoral intramedullary nail system includes a main nail, a head-neck nail, an anti-varus screw, and a distal locking screw. The distal end of the main nail has a distal locking hole in which the distal locking screw is installed. The proximal end of the main nail has, from proximal to distal, a head-neck nail hole, an anti-varus screw hole, and a distal locking hole, in which the head-neck nail, the anti-varus screw, and the distal locking screw are installed respectively. After the anti-varus screw passes through the anti-varus screw hole, its head is located in the head-neck nail groove. The main nail, the head-neck nail, and the anti-varus screw form a triangular stable support.

[0008] The head and neck nail is provided with a U-shaped groove along its axial direction. The head of the anti-inward rollover nail is located in the U-shaped groove and can slide along the U-shaped groove.

[0009] The included angle between the U-shaped groove head neck nail and the anti-inward rollover support nail is any value between 0° and 45°.

[0010] The anti-rollover pin hole is an oblique hole, with an angle between 45° and 60° with the horizontal line.

[0011] The anti-inward rollover pin hole is configured with a threaded structure.

[0012] The end face of the proximal end of the master nail is provided with a groove.

[0013] The end face of the proximal end of the master nail is provided with a tail cap.

[0014] The distal locking hole is unthreaded, and the distal locking pin is a regular screw that passes through the bone cortex and through the locking pin hole to achieve fixation.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared to traditional technologies, this invention adds an anti-varus deformity support pin. This pin contacts the groove of the head and neck screw and supports it. The support pin is tightly attached to the medial cortex of the proximal femur, preventing the bone fragment from sliding outward. Even with negative support, it can prevent hip varus deformity, while not affecting the sliding of the head and neck screw, effectively preventing the head and neck screw from protruding. The main screw, head and neck screw, and support pin form a stable triangular support. The head and neck screw has two fulcrums, significantly shortening the lever arm and effectively reducing the pressure on the head and neck screw and main screw, preventing screw breakage. At the same time, the triangular plane also increases the anti-rotation effect. One design achieves multiple purposes, providing multiple benefits.

[0016] By optimizing the structural design, additional and reliable mechanical fulcrums are provided for the head and neck screws to distribute stress, significantly reducing the risk of fatigue fracture of the main screw and head and neck screws. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Schematic diagram of the central master nail; Figure 3 for Figure 1 Schematic diagram of the head and neck screw; Figure 4 for Figure 1 Schematic diagram of the structure of the anti-inward flipping support pin; Figure 5 for Figure 1 A simulation diagram of the usage status; In the diagram: 1. Main nail; 2. Head and neck nail; 3. Anti-inward rollover nail; 4. Tail cap; 5. Distal locking nail; 6. Groove; 7. Head and neck nail hole; 8. Anti-inward rollover nail hole; 9. Distal locking hole; 10. U-shaped groove. Detailed Implementation

[0018] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0019] like Figures 1-5 As shown, a novel proximal femoral intramedullary nail system includes a main nail 1, a head-neck nail 2, an anti-varus screw 3, and a distal locking screw. The main nail 1 has a distal locking hole at its distal end, in which the distal locking screw is installed. From proximal to distal, the main nail 1 has a head-neck nail hole 7, an anti-varus screw hole 8, and a distal locking hole, in which the head-neck nail 2, the anti-varus screw 3, and the distal locking screw are respectively installed. The anti-varus screw 3 exits through the anti-varus screw hole 8, and its head is positioned within the groove of the head-neck nail 2. The main nail 1, head-neck nail 2, and anti-varus screw 3 form a stable triangular support. In biomechanics, a triangle is the most stable structure. This design transforms the traditional "single screw (head and neck screw 2) weight-bearing" mode of proximal femoral intramedullary nails into a "triangular support combined weight-bearing" mode, bringing revolutionary advantages: effectively preventing the femoral head from collapsing inward and downward under weight (i.e., varus deformity), which is the most common form of internal fixation failure in proximal femoral fractures. By distributing stress to three components and bone tissue, excessive stress concentration on the head and neck screw 2 is avoided, thus greatly reducing the risk of the head and neck screw 2 cutting through bone, penetrating the femoral head, or breaking, preventing varus deformity while supporting the head and neck screw 2.

[0020] The head and neck screw 2 is provided with a U-shaped groove 10 along its axial direction. The head of the anti-inversion screw 3 is located within the U-shaped groove 10 and can slide along the U-shaped groove 10. This allows the head and neck screw 2 to slide controllably along its axial direction when under load, thereby achieving automatic compression of the fracture ends, ensuring close contact of the fracture surfaces, and promoting healing. It also addresses the two crucial and sometimes contradictory needs in fracture healing: "dynamic compression" and "continuous stability."

[0021] The included angle between the U-shaped groove 10-head cervical screw 2 and the anti-inversion support screw 3 is any value between 0° and 45°. This allows surgeons to select the most suitable support angle based on different fracture types and patient anatomical differences, achieving individualized treatment and optimal mechanical support.

[0022] The anti-inward rollover pin hole 8 is an oblique hole, with an angle between it and the horizontal line of any value between 45° and 60°.

[0023] The anti-inward rollover pin hole 8 is configured with a threaded structure.

[0024] The anti-inward rollover pin 3 has a threaded hole for locking the tail of the anti-inward rollover pin 3.

[0025] A tail cap 4 is provided on the proximal end face of the main nail 1. This seals the entrance at the proximal end of the main nail 1, preventing bone ingrowth into the threads or interior of the main nail 1, and facilitating possible removal surgery in the future.

[0026] The proximal end face of the main nail 1 is provided with a groove 6, which is used to assist in applying pressure to the head and neck nail 2 during the operation in conjunction with other tools, thereby reducing the risk of it penetrating.

[0027] The distal locking hole 9 is unthreaded. The distal locking pin passes through the lateral cortex, then through the locking hole, and finally through the medial cortex to achieve fixation.

[0028] The steps for using this invention are as follows: Step 1: After fracture reduction, the main nail is inserted. An opening is made at the top of the greater trochanter of the femur or at the corresponding needle insertion point, and the medullary canal is expanded.

[0029] Insert the appropriate size master nail and allow it to descend smoothly along the femoral medullary cavity.

[0030] Adjust the depth of the master nail under fluoroscopy to ensure its proximal position is appropriate, so that the axis of the head and neck nail hole and the anti-varus nail hole can obtain good lateral and anteroposterior fluoroscopic images of the femoral neck-head.

[0031] Step 2: Implanting the head and neck nail A guide pin is inserted into the subchondral bone of the femoral head through the head and neck screw hole proximal to the main screw.

[0032] After drilling a stepped hole along the guide pin, select a head and neck pin of appropriate length.

[0033] Screw the head and neck screw into the predetermined position. Key points: Ensure that the tip of the head and neck screw is located approximately 10 mm below the femoral head and is centered on both anteroposterior and lateral fluoroscopy views. At this point, the U-shaped groove on the axial direction of the head and neck screw should be aligned with the expected implantation path of the anti-varus screw (marked on the screwing tool).

[0034] Step 3: Implant anti-inversion brace to construct triangular support. The guide pin is inserted through the anti-inversion pin hole near the master pin (which is an oblique hole at 45-60° to the horizontal line and has internal threads).

[0035] After drilling along the guide pin, select an anti-inward rollover pin of appropriate length.

[0036] Screw in the anti-varus pin, allowing it to pass through the threaded hole of the master pin and proceed forward and upward. Key points: Under fluoroscopic monitoring, continue screwing in close to the medial cortex of the proximal femur until the head of the anti-varus pin precisely enters the U-shaped groove of the head-neck pin and contacts the bottom of the groove.

[0037] Continue tightening. At this point, the head of the anti-varus screw is positioned within the U-shaped groove, with its shaft pressed against the medial cortex of the proximal femur. The main screw, the head-neck screw, and the anti-varus screw together form a stable "triangular support" structure.

[0038] Step 4: Perform auxiliary pressurization (optional, but recommended) At this point, the groove on the near end face of the master nail can be used in conjunction with a special pressure tool.

[0039] Step 5: Install the remote locking pin Using a sight or manual technique, a distal locking pin is inserted percutaneously through the distal locking hole at the distal end of the master pin.

[0040] This prevents the main nail from rotating and shifting axially within the medullary cavity, thus controlling the stability of the femur along its entire length.

[0041] Step 6: Install the tail cap and close the slit. Finally, screw the tail cap into the thread near the master nail to seal the near-end entrance of the master nail.

[0042] Function: Prevents bone ingrowth, facilitating future removal; at the same time, it smooths the proximal contour, reducing soft tissue irritation.

[0043] The incision was thoroughly rinsed and sutured layer by layer to complete the surgery.

[0044] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A novel proximal femoral intramedullary nail system, characterized in that, The device includes a main nail, a head and neck nail, an anti-inversion support nail, and a distal locking nail. The distal end of the main nail has a distal locking hole in which the distal locking nail is installed. The proximal end of the main nail has, from proximal to distal, a head and neck nail hole, an anti-inversion support nail hole, and a distal locking hole, in which the head and neck nail, the anti-inversion support nail, and the distal locking nail are installed respectively. After the anti-inversion support nail passes through the anti-inversion support nail hole, its head is located in the head and neck nail groove. The main nail, the head and neck nail, and the anti-inversion support nail form a triangular stable support, which at the same time prevents the proximal cortex from shifting outward, thereby preventing inversion deformity.

2. The novel proximal femoral intramedullary nail system according to claim 1, characterized in that, The head and neck nail is provided with a U-shaped groove along its axial direction. The head of the anti-inverting support nail is located in the U-shaped groove and can slide along the U-shaped groove. The head of the head and neck nail is provided with a threaded structure.

3. The novel proximal femoral intramedullary nail system according to claim 2, characterized in that, The included angle between the U-shaped groove head neck nail and the anti-inward rollover support nail is any value between 0° and 45°.

4. The novel proximal femoral intramedullary nail system according to claim 3, characterized in that, The anti-rollover pin hole is an oblique hole, with an angle between 45° and 60° between it and the horizontal line.

5. The novel proximal femoral intramedullary nail system according to claim 4, characterized in that, The anti-inward rollover pin hole is configured with a threaded structure.

6. The novel proximal femoral intramedullary nail system according to claim 5, characterized in that, The proximal end face of the head and neck nail is provided with a groove.

7. The novel proximal femoral intramedullary nail system according to claim 6, characterized in that, The end face near the main nail is provided with a tail cap.

8. The novel proximal femoral intramedullary nail system according to any one of claims 1-7, characterized in that, The distal locking hole is provided with no threads, and the distal locking pin passes through the locking pin hole through the bone cortex to achieve the fixation function.

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