A bidirectional self-expanding internal fixation system and method for femoral metaphyseal fractures

Abstract

The application provides a bidirectional self-expanding internal fixation system and method for femoral metaphyseal fracture, and belongs to the technical field of orthopedic medical instruments, and comprises: an intramedullary nail, a bidirectional self-expanding locking nail, and a visible and controllable self-expanding platform; the intramedullary nail is implanted in a femoral medullary cavity; the bidirectional self-expanding locking nail is implanted in a pre-hole of a femoral metaphysis and cooperates with a locking hole formed on the intramedullary nail; and the visible and controllable self-expanding platform is used for controlling and displaying the expansion size of the bidirectional self-expanding locking nail. The application has the advantages of simple structure, convenient operation, reduced operation difficulty, relatively small damage to patients, low manufacturing cost and convenience for promotion.

Description

Technical Field

[0001] This invention relates to the field of orthopedic medical device technology, specifically to a bidirectional self-expanding internal fixation system and method for femoral metaphysis fractures. Background Technology

[0002] As one of the main weight-bearing bones of the lower limb, fractures involving the femur are among the most common fractures in clinical practice. With the increasing aging of society and the growing awareness of exercise and fitness among the general public, the incidence of femoral metaphysis fractures near joints is also rising. Due to their proximity to joints, surgical treatment of femoral metaphysis fractures is challenging, difficult, and high-risk; even slight errors can lead to postoperative vascular damage. The classic surgical treatment method currently involves open reduction and internal fixation with plates and titanium cables. This method achieves ideal results for simple, stable fractures. However, if the patient has an unstable fracture or osteoporosis, the limitations of this method are very obvious, mainly in the following aspects:

[0003] 1. The femoral metaphysis is mostly cancellous bone, and the holding force of traditional nail-plate systems is relatively weak, so the fixation strength cannot meet the needs of early rehabilitation;

[0004] 2. The plate and nail system lacks a stabilizing mechanism to prevent displacement of the fractured ends of cancellous bone;

[0005] 3. If titanium cable fixation is required, it will cause significant damage to the blood supply to the periosteum, seriously affecting fracture healing. Summary of the Invention

[0006] The purpose of this invention is to provide a bidirectional self-expanding internal fixation system for femoral metaphysis fractures and its method of use.

[0007] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows:

[0008] A bidirectional self-expanding internal fixation system for femoral metaphysis fractures includes: an intramedullary nail, a bidirectional self-expanding locking nail, and a visually controllable self-expanding platform;

[0009] The intramedullary nail is implanted into the femoral medullary cavity; the bidirectional self-expanding locking nail is implanted into a pre-hole in the femoral metaphysis and cooperates with a locking hole opened on the intramedullary nail; the visual and controllable self-expanding platform is used to control and display the expansion size of the bidirectional self-expanding locking nail;

[0010] The bidirectional self-expanding locking pin includes two self-expanding locking pins fixedly connected as one unit; the self-expanding locking pin includes a middle section, an expandable opening bracket, an end section, and a drive screw; the expandable opening bracket is disposed between the middle section and the end section; the self-expanding locking pin has a hollow operating cavity inside; the drive screw is disposed inside the operating cavity, one end of which is threadedly connected to the distal internal thread opened on the inner wall of the middle section, and the other end of which is threadedly connected to the proximal internal thread opened on the inner wall of the end section;

[0011] The visible and controllable self-expanding platform includes a worm, a worm wheel, and a housing; the worm and the worm wheel are meshed inside the housing; both ends of the worm extend outside the housing, one end of which can be detachably connected to the drive screw, and the other end is used to control rotation; a worm wheel shaft is fixedly provided at the center of the worm wheel, and a pointer is fixedly provided at the other end of the worm wheel shaft, with a corresponding scale on the pointer.

[0012] Based on the above scheme and as a preferred embodiment of the above scheme, the expandable opening bracket includes several expandable connecting plates, each expandable connecting plate including two connecting plates, which are flexibly connected to each other, and the ends of the two connecting plates are respectively flexibly connected to the middle section and the end section.

[0013] Based on the above solution and as a preferred embodiment, a limit rod is provided on the housing; the limit rod can lock the worm gear.

[0014] Based on the above scheme and as a preferred embodiment of the above scheme, it further includes an insertion handle and a proximal aiming bracket; one end of the insertion handle is adapted to be connected to the intramedullary nail connection hole opened at the end of the intramedullary nail, and the other end is fixedly connected to the proximal aiming bracket.

[0015] A method of using the above-mentioned bidirectional self-expanding internal fixation system for femoral metaphysis fractures includes the following steps:

[0016] Step 1: Before surgery, examine the width of the patient's medullary canal and the fracture gap under CT or X-ray, and select an appropriate intramedullary nail for surgery based on the width of the patient's medullary canal;

[0017] Step 2: Pre-drilling holes; including intramedullary nail implantation holes and bidirectional self-expanding locking nail implantation holes;

[0018] Step 3: Calculate the expansion size of the bidirectional self-expanding locking pin. The calculation method is as follows: When the bidirectional self-expanding locking pin is in its unexpanded natural state, it is a straight line. Assuming the length of a single arm of the expandable stent is R, the depth of the drive screw is Δ, the distance the center point of the expandable stent moves backward relative to its original position is x, and the diameter of the bidirectional self-expanding locking pin implantation hole is h, the height h1 of the bidirectional self-expanding locking pin expanded inside the implantation hole can be obtained as h / 2. The expansion height h can be calculated using the following formula:

[0019] R-△+x 2 +h1 2 =R 2

[0020] Rx 2 +h1 2 =R 2

[0021] After calculating the screw-in depth △, the expansion size of the expandable opening bracket can be precisely controlled according to the dial.

[0022] Step 3: Implantation of the intramedullary nail; The intramedullary nail is implanted into the medullary cavity using specific instruments;

[0023] Step 4: Implant the bidirectional self-expanding locking pin; insert the bidirectional self-expanding locking pin into the implantation hole;

[0024] Step 5: Control the expansion of the bidirectional self-expanding locking pin through the visual and controllable self-expanding platform; use the worm gear and drive screw to connect, rotate the worm gear to drive the drive screw to rotate, and then drive the expandable opening bracket to expand to the predetermined size, and then disassemble the visual and controllable self-expanding platform.

[0025] The beneficial effects of this invention are:

[0026] Compared to traditional methods of fixing fracture fragments along the fracture line, this invention features a bidirectional self-expanding locking nail opening bracket that expands and presses against each other in different fracture fragments, causing the fracture fragments to press against each other. At the same time, it is combined with a visual and controllable self-expanding platform to precisely control the distance of expansion and pressurization, effectively preventing the fracture gap from being compressed due to excessive expansion, and ensuring that blood supply to the fracture is not obstructed.

[0027] Meanwhile, the invention has a simple structure, is easy to operate, can reduce the difficulty of surgery, causes relatively little damage to patients, has low manufacturing cost, and is easy to promote. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the bidirectional self-expanding locking pin in its natural state according to the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the bidirectional self-expanding locking pin in its expanded state according to the present invention;

[0030] Figure 3 This is a cross-sectional view of the bidirectional self-expanding locking pin of the present invention in its expanded state;

[0031] Figure 4 This is a structural diagram of the device used in this invention to implant a self-expanding intramedullary nail into the femoral medullary cavity;

[0032] Figure 5 This is a front view of the visible and controllable self-expanding platform structure of the present invention;

[0033] Figure 6 This is a cross-sectional view of the visible and controllable self-expanding platform structure of the present invention;

[0034] Figure 7 for Figure 6 Enlarged view of a specific area;

[0035] Figure 8 This is a schematic diagram of the self-expansion implementation scheme of the present invention;

[0036] In the diagram: 1. Intramedullary nail; 2. Bidirectional self-expanding locking nail; 21. Mid-section; 22. Expandable opening support; 23. End section; 24. Drive screw; 25. Distal internal thread; 26. Proximal internal thread; 3. Visual and controllable self-expanding platform; 31. Worm gear; 32. Worm wheel; 33. Housing; 34. Worm wheel shaft; 35. Pointer; 36. Dial; 37. Limiting rod; 38. Bearing; 39. Key; 4. Insertion handle; 5. Proximal aiming support. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 4 As shown, a bidirectional self-expanding internal fixation system for femoral metaphysis fractures includes: an intramedullary nail 1, a bidirectional self-expanding locking nail 2, a visually controllable self-expanding platform 3, an insertion handle 4, and a proximal aiming bracket 5;

[0039] Intramedullary nail 1 is inserted into the femoral medullary canal through an opening at the distal femur. A bidirectional self-expanding locking nail 2 is inserted into a pre-drilled hole in the femoral metaphysis and engages with a locking hole on intramedullary nail 1. A visually controllable self-expanding platform 3 is used to control and display the expansion size of the bidirectional self-expanding locking nail 2. An insertion handle 4 is used to insert intramedullary nail 1 into the medullary canal. A proximal aiming bracket 5 is used to aim at the pre-drilled hole to facilitate the insertion of the locking nail.

[0040] like Figures 1 to 3 As shown, the bidirectional self-expanding locking screw 2 includes two self-expanding locking screws fixedly connected as one unit. Preferably, the two self-expanding locking screws have the same structure and size and are symmetrically arranged about the axis of the intramedullary nail 1.

[0041] The self-expanding locking pin includes a middle section 21, an expandable opening bracket 22, an end section 23, and a drive screw 24. The expandable opening bracket 22 is located between the middle section 21 and the end section 23 and can expand to a size suitable for fixing the locking pin. The self-expanding locking pin has a hollow operating cavity that extends through the end section 23 but does not penetrate the middle section 21. The drive screw 24 is located inside the operating cavity, with one end threaded to a distal internal thread 25 on the inner wall of the middle section 21 and the other end threaded to a proximal internal thread 26 on the inner wall of the end section 23. The threads on the drive screw 24 corresponding to the distal and proximal internal threads 25 are opposite in direction, causing the middle section 21 and the end section 23 to move closer or further apart during rotation. The middle sections 21 of the two self-expanding locking pins are joined together to form a single unit.

[0042] Furthermore, the end of the drive screw 24 has an inner groove to connect to the visible and controllable self-expanding platform 3.

[0043] Preferably, such as Figure 7 As shown, the expandable opening bracket 22 includes several expandable connecting plates 221 evenly distributed circumferentially along the bidirectional self-expanding locking pin 2. Each expandable connecting plate 221 includes two connecting plates 2211, which are bendably connected. The ends of the two connecting plates 2211 are respectively bendably connected to the middle section 21 and the end section 23. When the bidirectional self-expanding locking pin 2 is in its unexpanded natural state, the connecting plates 2211 are slightly tilted to facilitate easy expansion.

[0044] like Figure 5 and Figure 6 As shown, the visible and controllable self-expanding platform 3 includes a worm gear 31, a worm wheel 32, and a housing 33. The worm gear 31 meshes with the worm wheel 32, and the meshing point is located inside the housing 3. Both ends of the worm gear 31 extend outside the housing 33. One end can be detachably connected to the drive screw 24, and the other end is used to control rotation. During operation, the worm gear 31 can be rotated by holding this end to drive the drive screw 24 to rotate. Optionally, the worm gear 31 is rotatably connected to the housing 33 through a bearing 38. The end of the worm gear 31 is provided as a polygonal pin, which can be inserted into the inner groove of the end of the drive screw 24 to drive the drive screw 24 to rotate.

[0045] A worm gear shaft 34 is fixedly mounted at the center of the worm gear 32, and a pointer 35 is fixedly mounted at the other end of the worm gear shaft 34. A dial 36 is correspondingly mounted on the pointer 35. Specifically, the worm gear 32 and the worm gear shaft 34 are fixedly connected by a key 39, so that the pointer 35 rotates together with the worm gear 32. Preferably, both the pointer 35 and the dial 36 are located inside the housing 33, and transparent portions are provided at corresponding locations for observation and protection.

[0046] Furthermore, a limit rod 37 is provided on the housing 33; the limit rod 37 can lock the worm gear 32. Specifically, the limit rod 37 is rotatably connected to the housing 33 and can be screwed into the housing 33 to lock the worm gear 32 to prevent the pointer 35 from rotating, thus self-locking the visible and controllable self-expanding platform 2.

[0047] Furthermore, the dial 36 has values ​​from 1 to 80, with each interval representing 0.1 mm. The large transmission ratio of the worm gear 31 and worm wheel 32 amplifies minute displacements. Specifically, the transmission ratio of the worm gear 31 to the worm wheel 32 is 1:20. The expandable bracket 22 is opened by the drive screw 24. After opening, rotating the limiting rod 37 locks the entire visible and controllable self-expanding platform 2. At this point, the value on the dial 36 indicates the depth to which the drive screw 24 has been screwed in.

[0048] One end of the insertion handle 4 is adapted to connect with the intramedullary nail connection hole opened at the end of the intramedullary nail 1 to facilitate the implantation of the intramedullary nail 1.

[0049] The proximal aiming bracket 5 is fixedly connected to the other end of the insertion handle 4, which facilitates aiming at the pre-hole for precise implantation of the locking pin.

[0050] A method of using the bidirectional self-expanding internal fixation system for femoral metaphysis fractures as described above includes the following steps:

[0051] Step 1: Before surgery, examine the width of the patient's medullary canal and the fracture gap under CT or X-ray, and select an appropriate intramedullary nail for surgery based on the width of the patient's medullary canal;

[0052] Step 2: Pre-hole preparation; including the intramedullary nail 1 implantation hole and the bidirectional self-expanding locking nail 2 implantation hole;

[0053] Step 3: Calculate the expansion size of the bidirectional self-expanding locking pin 2; the calculation method is as follows: Figure 8 As shown, when the bidirectional self-expanding locking pin 2 is in its unexpanded natural state, it is a straight line. Assuming the length of a single arm of the expandable opening stent 22 is R, the depth of the drive screw 24 is Δ, the distance the center point of the expandable stent 21 moves backward relative to its original position is x, and the diameter of the bidirectional self-expanding locking pin implantation hole is h, the height h1 of the bidirectional self-expanding locking pin 2 expanded inside the implantation hole can be obtained as h / 2. The expansion height h1 can be calculated using the following formula:

[0054] R-△+x 2 +h1 2 =R 2

[0055] Rx 2 +h1 2 =R 2

[0056] After calculating the screw-in depth △, the expansion size of the expandable opening bracket 22 can be precisely controlled according to the scale 36;

[0057] For example, assuming the diameter of the pre-hole for implanting the bidirectional self-expanding locking nail is 10mm, the expansion height required for the expandable opening stent 22 is h1 = 5mm. Given that the single arm length of the expandable opening stent is R = 15mm (in this embodiment, the single arm length is the length of the connecting plate 2211), Δ = 1.72mm can be calculated according to the above formula.

[0058] Step 3: Implantation of intramedullary nail 1; The intramedullary nail 1 is implanted into the medullary cavity using a specific instrument. In this embodiment, after connecting the insertion handle 4 to the connection hole at the end of the intramedullary nail 1, the intramedullary nail 1 is implanted retrogradely into the femoral medullary cavity by tapping or rotating the insertion handle 4.

[0059] Step 4: Implant the bidirectional self-expanding locking pin 2; Insert the bidirectional self-expanding locking pin 2 into the implantation hole;

[0060] Step 5: Control the expansion of the bidirectional self-expanding locking pin 2 via the visible and controllable self-expanding platform 3; connect the worm gear 31 to the drive screw 24, rotate the worm gear 31 to drive the drive screw 24 to rotate, thereby expanding the expandable opening bracket 22 to the predetermined size, and then disassemble the visible and controllable self-expanding platform 2. This invention has two expandable opening brackets 22. During expansion, two sets of visible and controllable self-expanding platforms 3 can be used for simultaneous expansion, or one set of visible and controllable self-expanding platforms 3 can be used for expansion one by one.

[0061] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A bidirectional self-expanding internal fixation system for femoral metaphysis fractures, characterized in that, include: Intramedullary nail (1), bidirectional self-expanding locking nail (2), visual and controllable self-expanding platform (3); The intramedullary nail (1) is implanted in the femoral medullary cavity; the bidirectional self-expanding locking nail (2) is implanted in a pre-hole in the femoral metaphysis and cooperates with the locking hole opened on the intramedullary nail (1); the visual and controllable self-expanding platform (3) is used to control and display the expansion size of the bidirectional self-expanding locking nail (2); The bidirectional self-expanding locking pin (2) includes two self-expanding locking pins fixedly connected as one unit; the self-expanding locking pin includes a middle section (21), an expandable opening bracket (22), an end section (23), and a drive screw (24); the expandable opening bracket (22) is disposed between the middle section (21) and the end section (23); the self-expanding locking pin has an operating cavity in its hollow interior; the drive screw (24) is disposed inside the operating cavity, one end of which is threaded to the distal internal thread (25) opened on the inner wall of the middle section (21), and the other end of which is threaded to the proximal internal thread (26) opened on the inner wall of the end section (23); The expandable opening bracket (22) includes several expandable connecting plates (221), each expandable connecting plate (221) including two connecting plates (2211), which are bendable and connected, and the ends of the two connecting plates (2211) are bendable and connected to the middle section (21) and the end section (23) respectively. The visible and controllable self-expanding platform (3) includes a worm (31), a worm wheel (32), and a housing (33); the worm (31) and the worm wheel (32) are meshed inside the housing (33); both ends of the worm (31) extend outside the housing (33), one end can be detachably connected to the drive screw (24), and the other end is used to control rotation; a worm wheel shaft (34) is fixedly provided at the center of the worm wheel (32), and a pointer (35) is fixedly provided at the other end of the worm wheel shaft (34), and a scale (36) is provided corresponding to the pointer (35); A limit rod (37) is provided on the housing (33); the limit rod (37) can lock the worm gear (32). Calculate the expansion size of the bidirectional self-expanding locking pin (2); the calculation method is as follows: when the bidirectional self-expanding locking pin (2) is in its unexpanded natural state, it is a straight line. Let the length of the single arm of the expandable opening bracket (22) be R, the depth of the drive screw (24) screwing in be △, the distance the center point of the expandable opening bracket (22) moves backward relative to its original position be x, and the diameter of the bidirectional self-expanding locking pin implantation hole be h. The height h1 of the bidirectional self-expanding locking pin (2) expanded inside the implantation hole can be obtained as h1 = h / 2. The expansion height h1 can be calculated using the following formula: (R-△+x) 2 +h1 2 =R 2 (Rx) 2 +h1 2 =R 2 After calculating the screw-in depth △, the expansion size of the expandable opening bracket (22) can be precisely controlled according to the dial (36).

2. The bidirectional self-expanding internal fixation system for femoral metaphysis fractures according to claim 1, characterized in that, It also includes an insertion handle (4) and a proximal aiming bracket (5); one end of the insertion handle (4) is adapted to be connected to the intramedullary nail connection hole opened at the end of the intramedullary nail (1), and the other end is fixedly connected to the proximal aiming bracket (5).

Images