CN108065996A - A kind of two parts intramedullary nail Fracture internal fixaiion system - Google Patents

Abstract

The present invention is a two-part intramedullary nail fracture internal fixation system, said intramedullary nail fracture internal fixation system includes intramedullary nail A part, intramedullary nail B part; said intramedullary nail A part and intramedullary nail B part It is a detachable connection; the intramedullary nail A part and the intramedullary nail B part are equipped with fixing screws. Its advantages are as follows: a two-part intramedullary nail fracture internal fixation system of the present invention is implanted through the broken end of the fracture to promote bone tissue healing. It has a simple structure, reasonable design, convenient operation during the operation, and can effectively fix the fracture. Effective functional exercise earlier.

Description

A two-part intramedullary nail fracture internal fixation system

technical field

The invention relates to the technical field of medical devices, in particular to an intramedullary nail fixation system for long bone shaft fractures.

Background technique

Fractures of the long bones of the extremities are relatively common. After the fracture occurs, the function of the limbs is greatly affected. Most of the unstable fractures need to be treated by surgery. The purpose of treatment is to restore the continuity of the fracture and achieve a strong fixation that allows early activities. Fixation systems include plate/screw systems and intramedullary nail systems.

In clinical application, the existing internal fixation systems have the following limitations.

During the installation of the plate/screw system, there is a high requirement for the exposure of the surgical area, and the damage to the surrounding structures of the fracture is relatively large. risk of non-healing etc.

The invention of the intramedullary nail system has brought about a revolutionary change in the treatment of long bone shaft fractures. However, the existing intramedullary nail system needs to be implanted through the end of the long bone, which is contraindicated for adolescents and children with unhealed epiphyses. The nail system does not expose the fracture end, and there is a possibility that anatomical reduction and soft tissue incarceration of the fracture end may not be possible, which will have a certain impact on fracture healing.

Chinese patent literature CN200920278252.5, application date 20091224, the patent name is: a proximal femoral intramedullary nail system, which discloses a proximal femoral intramedullary nail system, which consists of a hollow intramedullary nail, a set of tail nails, a Lag screw and interlocking screw are combined. The proximal end of the intramedullary nail is provided with an oblique lag screw hole, and the opposite distal end is provided with a long slotted hole through which the interlocking screw passes; the proximal lag screw hole is an ellipse to prevent its rotation. hole; the lag screw is composed of a rotating blade, a sliding sleeve nut, a connecting screw and a connecting sleeve. Among them, a set of helical grooves is provided on the upper part of the rotating blade, and the tail of the rotating blade and the front of the sliding sleeve nut are provided with mutually engaging ends. Teeth; the tail of the rotating blade and the sliding sleeve nut are occlusally connected through connecting screws, and the connecting sleeve is sleeved on the combined sliding sleeve nut and rotating blade, and the outer surface of the connecting sleeve is an oval hole with the intramedullary nail The corresponding elliptical cylinder.

The proximal femoral intramedullary nail system in the above patent document is particularly suitable for treating peritrochanteric femoral fractures in patients with osteoporosis. It facilitates the insertion of the intramedullary nail from the apex of the trochanter and facilitates the operation. However, there is no corresponding disclosure about a technical scheme that promotes bone tissue healing through implantation through the broken end of the fracture, is convenient to operate during the operation, can effectively fix the fracture, and enables the patient to perform effective functional exercises earlier.

In summary, there is a need for a two-part intramedullary nail system that can be implanted through the broken end of the fracture, promote bone tissue healing, be easy to operate during the operation, can effectively fix the fracture, and enable the patient to perform effective functional exercises earlier. A two-part intramedullary nail system has not been reported yet.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, to provide a two-part implant that promotes bone tissue healing through the broken end of the fracture, is easy to operate during the operation, can effectively fix the fracture, and enables the patient to perform effective functional exercises earlier. Intramedullary nailing system.

For realizing above-mentioned object, the technical scheme that the present invention takes is:

A two-part intramedullary nail fracture internal fixation system, the intramedullary nail fracture internal fixation system includes intramedullary nail A part, intramedullary nail B part; the intramedullary nail A part and intramedullary nail B part can be The connection is disassembled; the intramedullary nail part A and the intramedullary nail part B are equipped with fixing screws;

The A part of the intramedullary nail is a long tubular intramedullary nail; the free end of the A part of the intramedullary nail is provided with a fixing hole; the fracture end of the A part of the intramedullary nail is provided with a connecting part of the intramedullary nail ;

The B part of the intramedullary nail is a long tubular intramedullary nail; the free end of the B part of the intramedullary nail is provided with a fixing hole; the fracture end of the B part of the intramedullary nail is provided with an intramedullary nail b connecting part , the connecting part b of the intramedullary nail is detachably connected to the connecting part a of the intramedullary nail;

As a preferred technical solution, the internal fixation system further includes an intramedullary nail component A installation system, and the intramedullary nail A component installation system is a multi-directional screw installation device with a distal end.

As a preferred technical solution, the internal fixation system also includes a fracture assisting device, the fracture assisting device includes a spreader rod, a compression rod, a rotating groove, a contact plate, and a connecting rod; the support rod is In the structural form of the gear, the support rod is connected to the contact plate; the contact plate is provided with a rotating groove, and the connecting rod is connected to the pressing rod through the rotating groove.

As a preferred technical solution, it is characterized in that, the intramedullary nail a connecting part is provided with a bayonet, and the intramedullary nail a connecting part is a nut structure; the intramedullary nail b connecting part There is a b bayonet, and the b connecting part of the intramedullary nail is a threaded structure.

As a preferred technical solution, the intramedullary nail a connecting part is provided with a bayonet, and the intramedullary nail a connecting part is a fixed nut structure; the intramedullary nail b connecting part is provided with b Bayonet, and the connecting part of the intramedullary nail b is an active thread structure.

As a preferred technical solution, an embedding cavity is provided on the connecting part of the intramedullary nail a, and the embedding cavity is a square structure; a locking hole runs through the embedding cavity; on the connecting part of the intramedullary nail b A fitting block is provided, and a locking hole runs through the fitting block, and the locking hole corresponds to the locking hole penetrating through the embedding cavity; a locking screw is pierced in the locking hole.

As a preferred technical solution, the connecting part of the intramedullary nail a is provided with a first transverse half-section and a first longitudinal half-section, and a first V-shaped notch is provided on the first transverse half-section; The first longitudinal half section is provided with a first insertion hole; the end of the intramedullary nail a connecting part is provided with a first plug; the intramedullary nail b connecting part is provided with a second transverse half section and a first insertion hole. Two longitudinal half-sections, the second V-shaped notch is provided on the second transverse half-section; the second insertion hole is provided on the second longitudinal half-section; the end of the intramedullary nail a connecting part is provided with a first Two inserts; the second insert matches the first socket; the second insert matches the first insert; the assembled state of the first V-shaped notch and the second V-shaped notch A locking square hole is formed below, and a locking block is assembled in the locking square hole.

The present invention has the advantage that:

A two-part intramedullary nail fracture internal fixation system of the present invention is implanted through the broken end of the fracture to promote bone tissue healing. It has a simple structure, reasonable design, convenient operation during the operation, and can effectively fix the fracture, so that the patient can be effectively treated earlier. functional exercise;

2. The present invention is applicable to all kinds of simple or complex long bone fractures, and is also applicable to long bone fractures in children and adolescents with unclosed epiphysis, without the risk of damage to the epiphysis and metaphysis;

3. Equipped with auxiliary devices, which can be used to expand, reset and pressurize the fracture to its anatomical position. If necessary, the free fracture fragment can also be fixed by means of tension bands and other devices;

4. The connection between part B of the intramedullary nail and part A of the intramedullary nail is a detachable connection. This design method can be implanted through the broken end of the fracture, and can remove the incarcerated soft tissue of the broken end of the fracture and other tissues that affect fracture healing. , is conducive to the early growth and healing of bone tissue;

5. The internal fixation system does not involve the extraosseous periosteum system, which is beneficial to the healing of bone tissue after fracture and reduces the risk of delayed union and nonunion of fracture;

6. Part B of the intramedullary nail can be connected with part A of the intramedullary nail by threaded connection. The threaded connection makes part A of the intramedullary nail and part B of the intramedullary nail effectively fixed and not easy to fall off;

7. The threaded connection section between the B part of the intramedullary nail and the A part of the intramedullary nail can be adjusted, and the length of the threaded connection section can be adjusted according to the needs to ensure the exact fixation effect and achieve precise fixation;

8. By inserting the fitting block into the embedding cavity and locking it with the locking screw, the effect of this design scheme is: fast installation, simple structure, and convenient operation;

9. The connection between part B of the intramedullary nail and part A of the intramedullary nail adopts the mortise and tenon structure design, and the internal fixation is performed from multiple directions, and the internal fixation effect is accurate.

Description of drawings

Accompanying drawing 1 is a structural block diagram of a two-part intramedullary nail fracture internal fixation system of the present invention.

Accompanying drawing 2 is the schematic diagram of the assembly state of intramedullary nail A part and intramedullary nail B part.

Accompanying drawing 3 is the structure schematic diagram of intramedullary nail A component.

Accompanying drawing 4 is the structure schematic diagram of intramedullary nail B component.

Accompanying drawing 5 is the structure schematic diagram of intramedullary nail A component installation system.

Accompanying drawing 6 is a structural schematic diagram of the fracture assisting device.

Accompanying drawing 7 is the structure schematic diagram of the detachable connection mode in embodiment 2.

Accompanying drawing 8 is the structural diagram of the detachable connection mode in embodiment 3.

Accompanying drawing 9 is the structural diagram of the detachable connection mode in embodiment 4.

Accompanying drawing 10 is the assembly state schematic diagram in embodiment 5.

Accompanying drawing 11 is the schematic diagram of assembly and disassembly state in embodiment 6.

Detailed ways

The specific embodiments provided by the present invention will be described in detail below in conjunction with the accompanying drawings.

The reference signs and components involved in the accompanying drawings are as follows:

1. Part A of intramedullary nail 11. Fixation hole

12. Intramedullary nail a connecting part 121.a Bayonet

122. Insert cavity 123. First transverse section

124. The first jack 125. The first plug

126. First V-shaped notch 127. First longitudinal section

2. Part B of the intramedullary nail

21. Intramedullary nail b connection part 211.b bayonet

212. Fitting block 213. Second transverse half section

214. The second jack 215. The second plug

216. Second V-shaped notch 217. Second longitudinal half-section

3. Fixing screw

4. Locking screw 41. Locking hole

5. Lock block 51. Lock square hole

6. Intramedullary Nail Part A Installation System 7. Fracture Assist Device

71. Stretching rod 72. Compression rod

73. Rotary slot 74. Contact plate

76. Connecting rod

Example 1

Please refer to FIG. 1 . FIG. 1 is a structural block diagram of a two-part intramedullary nail fracture internal fixation system of the present invention. A two-part intramedullary nail fracture internal fixation system, the intramedullary nail fracture internal fixation system includes an intramedullary nail A component 1, an intramedullary nail B component 2, an intramedullary nail A component installation system 6, and a fracture assisting device 7.

Please refer to FIG. 2 , which is a schematic diagram of an assembled state of the intramedullary nail part A 1 and the intramedullary nail part B 2 . The intramedullary nail part A 1 and the intramedullary nail part B 2 are detachably connected; the intramedullary nail part A 1 and the intramedullary nail part B 2 are both equipped with fixing screws 3 .

Please refer to FIG. 3 . FIG. 3 is a schematic structural view of part A of the intramedullary nail. The intramedullary nail A component 1 is a long tubular intramedullary nail; the free end of the intramedullary nail A component 1 is provided with a fixing hole 11; the fracture end of the intramedullary nail A component 1 is provided with an intramedullary Nail a connection part 12.

Please refer to FIG. 4 , which is a schematic structural diagram of part B of the intramedullary nail. The intramedullary nail B part 2 is a long tubular intramedullary nail; the free end of the intramedullary nail B part 2 is provided with a fixing hole 11; the fracture end of the intramedullary nail B part 2 is provided with an intramedullary The nail b connecting part 21, the intramedullary nail b connecting part 21 is detachably connected with the intramedullary nail a connecting part 12.

Please refer to FIG. 5 . FIG. 5 is a schematic structural diagram of the intramedullary nail component A installation system 6 . The intramedullary nail component A installation system 6 is a multi-directional screw installation device with a distal end; the intramedullary nail component A installation system 6 can implant the intramedullary nail component A 1 into the fracture end through the fracture end, temporarily Fixed to become a reference.

Please refer to FIG. 6 , which is a schematic structural diagram of the fracture assisting device 7 . The fracture assisting device 7 includes a spreading rod 71, a pressurizing rod 72, a rotating groove 73, a contact plate 74, and a connecting rod 75; the support rod is in the form of a gear, and the support rod is connected to the contact plate 74; The contact plate 74 is provided with a rotation groove 73 , and the connecting rod 75 is connected with the pressing rod 72 through the rotation groove 73 . The fracture assisting device 7 is used for fracture distraction, reduction and compression. In the state of use, with reference to the intramedullary nail A component 1, it is temporarily implanted at the other end of the fracture away from the fracture line after crossing the fracture line. After operations such as distraction and rotation, the broken end of the fracture is reset, and pressure can be added if necessary.

What needs to be explained in this embodiment is:

Part B of the intramedullary nail can be implanted at the same time as part A of the intramedullary nail, or implanted after the fracture ends are distracted. The connecting part 21 is anastomosed with the intramedullary nail a connecting part 12 and then fixed to form a complete intramedullary nail; the installation device of the intramedullary nail B part 2 uses the intramedullary nail A part 1 as a reference to install the fixing screw 3, and finally the intramedullary nail Nail A Part 1 Temporary fixation/reference replaced with permanent fixation.

Intramedullary nail B part 2 can be detachably connected with intramedullary nail A part 1. This design can be implanted through the broken end of the fracture, and can remove the incarcerated soft tissue of the broken end of the fracture and other tissues that affect fracture healing. , is conducive to the early growth and healing of bone tissue. It is suitable for all kinds of simple or complex long bone fractures, and it is also suitable for long bone fractures in children and adolescents with unclosed epiphysis, without the risk of damage to the epiphysis and metaphysis.

Equipped with auxiliary devices for distraction, reduction and compression, the fracture can be reduced to an anatomical position, and if necessary, free fracture fragments can also be fixed by means of tension bands and other devices.

The installation method of a kind of two-part intramedullary nail fracture internal fixation system of the present invention is:

1. Take a suitable incision from the plane of the fracture end, expose the fracture end, install intramedullary nail A part 1, fix the distal end of the fracture with anti-rotation screws (1-2 pieces), and drill 2 Kirschner through the remaining nail hole channel Temporary fixation with pins/Steiner wires; (if conditions permit, implant B part 2 of the intramedullary nail at the same time)

2. Install the auxiliary device for fracture distraction/reduction/compression on the top of the Kirschner wire/Schner wire, on the other end of the fracture away from the fracture line (the distance from the fracture line > the length of B part 2 of the intramedullary nail) ) into 1-2 Kirschner wires/Schner wires;

3. Stretch the broken end of the fracture, the intramedullary nail B part 2 that cannot be implanted in step 1 can be implanted after the broken end of the fracture is stretched, and connect the two parts of the intramedullary nail A and B;

4. Reset and pressurize the broken end of the fracture;

5. Fix part B of the intramedullary nail (fixed in multiple different directions), remove the fracture distraction/reduction/compression device and all Kirschner wires/Schner wires, and fix the A part of the intramedullary nail with the remaining nail holes and screws. The installation of the intramedullary nail internal fixation system is completed.

Example 2

Please refer to FIG. 7 , which is a schematic structural diagram of the detachable connection method in Embodiment 2. Referring to FIG. This embodiment is basically the same as Embodiment 1, the difference is that the intramedullary nail a connecting part 12 in this embodiment is provided with a bayonet 121, and the intramedullary nail a connecting part 12 is a nut structure; The b-connecting part 21 of the intramedullary nail is provided with a b bayonet 211, and the b-connecting part 21 of the intramedullary nail is a threaded structure.

In this embodiment, the intramedullary nail a connecting part 12 and the intramedullary nail b connecting part 21 are threadedly connected, and the threaded connection enables the intramedullary nail A part 1 and the intramedullary nail B part 2 to be effectively fixed and not easy to fall off; The a bayonet 121 and the b bayonet 211 are inserted into the locking part, which can further fix the intramedullary nail A part 1 and the intramedullary nail B part 2, and prevent the intramedullary nail A part 1 and the intramedullary nail B part 2 from being displaced under pressure .

Example 3

Please refer to FIG. 8 . FIG. 8 is a schematic structural diagram of the detachable connection method in Embodiment 3. Referring to FIG. This embodiment 1 is basically the same as embodiment 1, the difference is that the intramedullary nail a connecting part 12 in this embodiment is provided with a bayonet 121, and the intramedullary nail a connecting part 12 is a fixed nut structure ; The b-connecting part 21 of the intramedullary nail is provided with a b bayonet 211, and the b-connecting part 21 of the intramedullary nail is a movable thread structure.

What needs to be explained in this embodiment is: the length of the threaded connection section on the connecting part 12 of the intramedullary nail a and the connecting part 21 of the intramedullary nail b is adjustable, and different connections produce different internal fixation forces, and Different types of fractures in different patients require different internal fixation forces. According to the method of this embodiment, the length of the threaded connection section can be adjusted as required to ensure a definite fixation effect and achieve precise fixation.

Example 4

Please refer to FIG. 9 . FIG. 9 is a schematic structural diagram of the detachable connection method in Embodiment 4. Referring to FIG. This embodiment is basically the same as Embodiment 1, the difference is that the intramedullary nail a connecting part 12 in this embodiment is provided with an embedding cavity 122, and the embedding cavity 122 is a square structure; the embedding cavity 122 runs through There is a locking hole; the connecting part 21 of the intramedullary nail b is provided with a fitting block 212, and the fitting block 212 is penetrated with a locking hole, and the locking hole corresponds to the locking hole through which the embedding cavity 122 penetrates; A locking screw 4 is pierced in the locking hole.

What needs to be explained in this embodiment is that the connecting part 12 of the intramedullary nail a and the connecting part 21 of the intramedullary nail b are inserted into the embedding cavity 122 by the fitting block 212 and locked by the locking screw 4. The effect of this design scheme is: It can be installed quickly, has a simple structure and is easy to operate.

Example 5

Please refer to FIG. 10 and FIG. 11 , FIG. 10 is a schematic diagram of the assembled state in Embodiment 5. Fig. 11 is a schematic diagram of the assembled and disassembled state in Embodiment 6. This embodiment is basically the same as Embodiment 1, the difference is that the intramedullary nail a connecting part 12 in this embodiment is provided with a first transverse half-section 123 and a first longitudinal half-section 127, the first transverse The half-section 123 is provided with a first V-shaped notch 126; the first longitudinal half-section 127 is provided with a first insertion hole 124; the end of the intramedullary nail a connecting part 12 is provided with a first insert 125; The connecting part 21 of the intramedullary nail b is provided with a second transverse half-section 213 and a second longitudinal half-section 217, and the second transverse half-section 213 is provided with a second V-shaped notch 216; A second socket 214 is provided on the half-section 217; a second insert 215 is provided at the end of the intramedullary nail a connecting part 12; the second insert 215 is matched with the first socket 124; The second socket 214 is matched with the first plug 125; the first V-shaped notch 126 and the second V-shaped notch 216 are assembled to form a locking square hole 51, and a locking square hole 51 is installed in the locking square hole 51. Block 5.

What needs to be explained in this embodiment is that the intramedullary nail a connecting part 12 and the intramedullary nail b connecting part 21 adopt a mortise and tenon structure design, which has the following technical effects: 1. When installing, only one of the sockets needs to be inserted into the other. It can be inserted into the block, and the installation is fast and accurate; 2. The intramedullary nail a connecting part 12 and the intramedullary nail b connecting part 21 perform internal fixation from multiple directions, such as between the first insertion hole 124 and the second insertion block 215 The fixing between the second socket 214 and the first plug 125; the fixing between the locking block 5 and the locking square hole 51 is fixed from the longitudinal direction and the lateral direction respectively, and the fixing effect is definite.

A two-part intramedullary nail fracture internal fixation system of the present invention is implanted through the broken end of the fracture to promote bone tissue healing. It has a simple structure, reasonable design, convenient operation during the operation, and can effectively fix the fracture, so that the patient can be effectively treated earlier. Functional forging; the present invention is suitable for various simple or complex long bone fractures, and is also suitable for long bone fractures in children and adolescents with unclosed epiphyses, without the risk of damage to the epiphysis and metaphysis; with auxiliary devices, it can be used to expand, reset and Pressurization can restore the fracture to the anatomical position. If necessary, the free fracture fragment can also be fixed by tension bands and other devices; the connection between the intramedullary nail B part 2 and the intramedullary nail A part 1 can be detachable. This design method can be implanted through the broken end of the fracture, and can remove the incarcerated soft tissue of the broken end and other tissues that affect fracture healing, which is conducive to the early growth and healing of bone tissue; the internal fixation system does not involve the extraosseous periosteum system, which is beneficial The bone tissue heals after the fracture, reducing the risk of delayed union and nonunion of the fracture; the connection between the intramedullary nail B part 2 and the intramedullary nail A part 1 adopts threaded connection, and the threaded connection makes the intramedullary nail A part 1 and the intramedullary nail part A Intramedullary nail B part 2 can be effectively fixed and is not easy to fall off; the thread connection section between intramedullary nail B part 2 and intramedullary nail A part 1 can be adjusted, and the length of the thread connection section can be adjusted according to needs to ensure the exact fixation effect. Accurate fixation is realized; by inserting the fitting block 212 into the embedding cavity 122 and locking it with the locking screw 4, the effect of this design scheme is: fast installation, simple structure, and convenient operation; part B of the intramedullary nail can be connected with the The connection between part A of the inner nail adopts a mortise and tenon structure design, and the internal fixation is performed from multiple directions, and the internal fixation effect is accurate.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the method of the present invention, some improvements and supplements can also be made, and these improvements and supplements should also be considered Be the protection scope of the present invention.

Claims (7)

1. A two-part intramedullary nail fracture internal fixation system is characterized in that, the intramedullary nail fracture internal fixation system includes intramedullary nail A part, intramedullary nail B part; described intramedullary nail A part and Part B of the inner nail is detachably connected; part A of the intramedullary nail and part B of the intramedullary nail are equipped with fixing screws; The A part of the intramedullary nail is a long tubular intramedullary nail; the free end of the A part of the intramedullary nail is provided with a fixing hole; the fracture end of the A part of the intramedullary nail is provided with a connecting part of the intramedullary nail ; The B part of the intramedullary nail is a long tubular intramedullary nail; the free end of the B part of the intramedullary nail is provided with a fixing hole; the fracture end of the B part of the intramedullary nail is provided with an intramedullary nail b connecting part , the connecting part b of the intramedullary nail is detachably connected to the connecting part a of the intramedullary nail. 2. The two-part intramedullary nail fracture internal fixation system according to claim 1, characterized in that, the internal fixation system also includes an intramedullary nail A component installation system, and the intramedullary nail A component installation system is a belt with a distal end Multi-directional screw mounting device. 3. The two-part intramedullary nail fracture internal fixation system according to claim 1, characterized in that, the internal fixation system also includes a fracture assisting device, and the fracture assisting device includes a spreader rod, a compression rod, Rotation groove, contact plate, connecting rod; the support rod is in the form of a gear, and the support rod is connected to the contact plate; the contact plate is provided with a rotation groove, and the connection rod is connected to the pressure rod through the rotation groove. 4. The two-part intramedullary nail fracture internal fixation system according to claim 1, wherein said intramedullary nail a connecting part is provided with a bayonet, and the intramedullary nail a connecting part is a nut structure ; The connecting part of the intramedullary nail b is provided with a b bayonet, and the connecting part of the intramedullary nail b is a threaded structure. 5. The two-part intramedullary nail fracture internal fixation system according to claim 1, wherein said intramedullary nail a connecting part is provided with a bayonet, and the intramedullary nail a connecting part is a fixing nut Structure; the b-connecting part of the intramedullary nail is provided with a b bayonet, and the b-connecting part of the intramedullary nail is a movable thread structure. 6. The two-part intramedullary nail fracture internal fixation system according to claim 1, wherein said intramedullary nail a connecting part is provided with an embedding cavity, and said embedding cavity is a square structure; A locking hole is penetrated; the connecting part of the intramedullary nail b is provided with a fitting block, the fitting block is penetrated with a locking hole, and the locking hole corresponds to the locking hole penetrating through the embedding cavity; the locking hole Threaded with locking screws. 7. The two-part intramedullary nail fracture internal fixation system according to claim 1, wherein said intramedullary nail a connecting part is provided with a first transverse half-section and a first longitudinal half-section, said second A first V-shaped notch is provided on a transverse half-section; a first insertion hole is provided on the first longitudinal half-section; a first insert is provided at the end of the intramedullary nail a connecting part; A second transverse half-section and a second longitudinal half-section are provided on the connecting part of the inner nail b, and a second V-shaped notch is provided on the second transverse half-section; a second jack is provided on the second longitudinal half-section The end of the connecting part of the intramedullary nail a is provided with a second plug; the second plug is matched with the first socket; the second socket is matched with the first plug; The first V-shaped notch and the second V-shaped notch are assembled to form a locking square hole, and a locking block is installed in the locking square hole.