CN215425023U

CN215425023U - Internal fixing device

Info

Publication number: CN215425023U
Application number: CN202023068590.1U
Authority: CN
Inventors: 李永杰; 王博; 刘丽亚
Original assignee: Tianjin Zhengtian Medical Instrument Co Ltd
Current assignee: Tianjin Zhengtian Medical Instrument Co Ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2022-01-07
Anticipated expiration: 2030-12-18

Abstract

The utility model provides an internal fixation device, which comprises a bone fracture plate, wherein the bone fracture plate is a combined type bone fracture plate and comprises: the two ends of the first bone fracture plate are respectively fixed on the first broken bone and the second broken bone; the two ends of the second bone fracture plate are respectively fixed on the first broken bone and the second broken bone; the first bone fracture plate and the second bone fracture plate are overlapped and can slide relatively after being overlapped. The internal fixation device can realize relative sliding of the first bone fracture plate and the second bone fracture plate through relative matching of the first bone fracture plate and the second bone fracture plate during stress, so that stress applied to broken bones is transferred to the first bone fracture plate and the second bone fracture plate, and then the broken bones are converted into relative motion of the combined bone fracture plate, stress concentration is avoided, the stress dispersion mode is unique, and the stress dispersion effect is better relative to the traditional bone fracture plate.

Description

Internal fixing device

Technical Field

The utility model belongs to the technical field of orthopedic medical instruments, and particularly relates to an internal fixing device.

Background

Fracture, a common type of injury in the orthopedic medical field, is divided into two major categories, namely, fracture of the articular surface and the vicinity thereof and long tubular fracture, wherein the long tubular fracture is a high-incidence type of fracture. In the field of orthopedic practice, bone fracture plate fixation of fracture is one of the most common and effective treatment methods in fixation treatment of long tubular fracture.

When the bone structure of a human body is completely or partially broken, a patient needs to be treated in time to enable the fracture to heal gradually, the fracture needs to be reinforced by using a bone fracture plate, the bone fracture plate can realize strong fixation, accelerate the healing of the fracture and avoid sequelae. When the fracture of a patient is serious, the fracture part of the bone structure needs to be pressurized by the bone fracture plate so as to ensure good healing of the fracture part. However, the existing pressurized bone fracture plate is generally a bone fracture plate, and the fracture part is pressurized by the bone fracture plate through the tensioning of screws at two ends of the bone fracture plate. In the using process, the bone plate has the following defects: when the screws at the two ends of the bone fracture plate are completely fixed, the fracture gap is not adjustable any more; if the second bone plate is removed and the compression fixation is performed again, the pain of the patient will be increased undoubtedly, and if the second bone plate is not adjusted, the rehabilitation of the patient will be not facilitated.

At present, the existing bone fracture plates are fixed at the fracture part by using screws to form strong internal fixation on the fracture area. Among them, the locking bone plate has the highest application range and frequency due to its superior stability. However, after the two broken ends of the fracture are connected and fixed by the locking screws, all the stress is transmitted to the locking bone fracture plate through the locking screws because the locking screws are driven into the bone to form stable connection, and the large stress is borne at the fixing positions of the hole positions of the locking bone fracture plate and the locking screws, so that the mechanical stress at the backbone position is enhanced after the fracture is fixed by the locking bone fracture plate, and the locking bone fracture plate completely or partially replaces the human skeleton to bear stress conduction, so that the stress at the fractured ends cannot be directly and effectively conducted, and the stress shielding effect is generated. The problems of stress shielding, stress concentration and the like of the traditional metal bone fracture plate are particularly prominent, and the bone fracture plate or a screw is easy to break, so that the conditions of bone nonunion and bone malformation healing are caused, and irreversible injury is caused to a patient.

It has been found that almost all fractures of metal bone plates occur at or closest to the corresponding screw holes at the fracture site. Fractured screw holes occur at the screw hole site where the screw is placed near the fracture end or at the screw hole site where the screw is not placed at the fracture corresponding site. And the substantial portion between the screw holes never has been fractured by the metal bone plate. Obviously, the nail hole part of the screw is embedded into or not embedded into the corresponding nail hole part of the fracture part of the metal bone fracture plate, and the part with the weakest stress concentration and stress resistance is the part without the embedded screw.

In order to solve the above problems, CN201721333571.2 discloses a stress-type compression locking bone fracture device, in which a gradually-changing stress groove is provided between any two adjacent locking holes and compression locking holes on a locking bone plate, so as to reduce the thickness of the edge of the stress-type bone plate, avoid the fracture of the stress-type bone plate caused by too concentrated stress of the stress-type bone plate, and prolong the service life of the stress-type bone plate; the stress through groove is formed between the two locking holes on the stress type bone plate, so that the rigidity between the locking holes is reduced, the metal elastic effect of the stress type bone plate is exerted, the local stress of the stress type bone plate is relieved, the stress is dispersed, the stress concentration and the stress shielding are avoided, and meanwhile, a certain micro-motion can be allowed to exist at the fracture end.

CN201822197492.4 discloses a modular variable stress coaptation board, through stop screw swing joint base plate A and base plate B, leave the clearance between base plate A and the base plate B, two base plates can produce the displacement through arch and spout to realize the conduction of the direct stress of upper and lower fracture end, solved the problem that the fracture end section of the upper and lower fracture end at current coaptation board both ends produced the stress and sheltered from.

CN201721323009.1 discloses a coaptation board of adjustable pretightning force, rotates adjusting screw through adjusting handle, can adjust the pretightning force of first mainboard and second mainboard to bone structure, can make the fracture department of bone structure reach required pretightning force, has realized the good healing of fracture department, is favorable to fracture department health recovery, has avoided the production of sequelae.

The technical scheme does not completely solve the problems of stress concentration, stress shielding and the like of the bone fracture plate, and the shear stress still exists. Meanwhile, the weight and the volume of the bone fracture plate are increased, and the injury to a patient is increased.

SUMMERY OF THE UTILITY MODEL

Aiming at the problems in the prior art, the utility model provides an internal fixing device, in particular to an internal fixing device specially used for fixing a long tubular fracture part, which has the advantages of simple structure, convenient use, capability of dispersing stress, avoidance of stress shielding, firmness and reliability, adjustable fracture gap and contribution to fracture healing.

In order to achieve the purpose, the technical scheme adopted by the utility model is as follows:

the utility model provides an internal fixation device, includes the coaptation board, the coaptation board is combination formula coaptation board, and it includes:

the two ends of the first bone fracture plate are respectively fixed on the first broken bone and the second broken bone;

the two ends of the second bone fracture plate are respectively fixed on the first broken bone and the second broken bone;

the first bone fracture plate and the second bone fracture plate are overlapped and can slide relatively after being overlapped.

The surface of the first bone fracture plate overlapped with the second bone fracture plate is provided with a first resistance structure; a second resistance structure is arranged on the surface of the second bone fracture plate overlapped with the first bone fracture plate; the first resistance structure and the second resistance structure can slide relatively after being matched.

The first resistance structure or the second resistance structure is one or a combination of at least two of a sawtooth structure, a convex and/or concave groove structure or a rough surface structure which are matched with each other.

The part of the first bone fracture plate fixed on the first broken bone is provided with a first locking hole, and the part of the first bone fracture plate fixed on the second broken bone is provided with a first sliding hole and optionally a first through hole;

the second bone fracture plate is provided with a second sliding hole corresponding to the first locking hole, a third sliding hole corresponding to the first sliding hole and a second locking hole corresponding to the first through hole;

a first locking piece is arranged in the first locking hole and the second sliding hole; a second locking piece is arranged in the first sliding hole and the third sliding hole; and a third locking piece is arranged in the second locking hole.

The first through hole is selected from a sliding hole and/or a locking hole.

The first locking aperture and the second locking aperture independently comprise a locking pressurization aperture.

The first, second, and third slip holes independently comprise oblong holes.

And Kirschner wire holes are correspondingly formed in the two ends of the first bone fracture plate and the second bone fracture plate.

The first bone plate and the second bone plate are independently straight plates or micro-arc plates.

The contact limiting groove is arranged on the surface of the combined bone fracture plate, which is in contact with the bone.

The internal fixing device has the advantages and positive effects that:

1. the internal fixing device provided by the utility model has a simple structure and is convenient to operate, and when the internal fixing device is stressed, the first bone fracture plate and the second bone fracture plate can slide relatively, so that the stress on broken bones is transferred to the first bone fracture plate and the second bone fracture plate and further converted into the relative motion of the combined bone plate, the stress concentration is avoided, the stress dispersion mode is unique, and the stress dispersion effect is better compared with that of the traditional bone fracture plate.

2. The first bone fracture plate and the second bone fracture plate in the internal fixing device provided by the utility model are in an up-down overlapping type, so that even if a force vertical to the backbone is applied to a fracture part, the fracture part can be stably fixed at the fracture part, the displacement of the broken bone can be prevented, and the bone fracture plate is ensured to be fixed more stably.

3. The thickness of the bone plate in the internal fixing device provided by the utility model is not reduced, so that the strength and the rigidity are consistent with those of the traditional bone plate, compared with the traditional single plate fixing, the impact of stress on the bone plate and the screw can be greatly reduced, and the fracture of the bone plate or the screw and the secondary fracture of the bone after the fracture is healed can be effectively avoided.

Drawings

Fig. 1 is a sectional view showing a state in which an internal fixation device according to an embodiment of the present invention is used.

Fig. 2 is a plan view of an internal fixation device provided in accordance with an embodiment of the present invention.

Fig. 3 is a schematic perspective view of an internal fixation device according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the first resistive structure and the second resistive structure being asymmetric saw tooth structures according to one embodiment of the present invention.

Fig. 5 is a schematic diagram of a symmetrical sawtooth structure for the first resistance structure and the second resistance structure according to an embodiment of the present invention.

Fig. 6 is a schematic view of the first resistance structure and the second resistance structure being groove or protrusion structures according to an embodiment of the present invention.

Fig. 7 is another schematic view of the first resistance structure and the second resistance structure being grooves or protrusions according to an embodiment of the present invention.

Fig. 8 is a schematic diagram of the first resistance structure and the second resistance structure being rough structures according to an embodiment of the present invention.

FIG. 9 is a top view of a first bone plate provided in accordance with one embodiment of the present invention.

FIG. 10 is a bottom view of a first bone plate provided in accordance with one embodiment of the present invention.

FIG. 11 is a cross-sectional view of a first bone plate provided in accordance with one embodiment of the present invention.

Fig. 12 is a perspective view of a second bone plate according to one embodiment of the present invention.

FIG. 13 is a top view of a second bone plate provided in accordance with one embodiment of the present invention.

FIG. 14 is a bottom view of a second bone plate provided in accordance with one embodiment of the present invention.

Fig. 15 is a cross-sectional view of a second bone plate provided in accordance with one embodiment of the present invention.

In the figure:

1. a first bone plate; 11. a first resistance structure; 12. a first k-wire hole; 13. a first locking hole; 14. a first sliding hole; 15. a first through hole;

2. a second bone plate; 21. a second resistance structure; 22. a second k-wire hole; 23. a second locking hole; 24. a second sliding hole; 25. a restraining contact groove; 26. a third sliding hole;

3. a first broken bone;

4. a second broken bone;

51. a first locking member; 52. a second locking member; 53. and a third locking member.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Embodiments of the utility model are further described below with reference to the accompanying drawings:

as shown in fig. 1-3, an internal fixation device includes a modular bone plate comprising a first bone plate 1 and a second bone plate 2 stacked together. Two ends of the first bone fracture plate 1 are respectively fixed on the first broken bone 3 and the second broken bone 4, and two ends of the second bone fracture plate 2 are respectively fixed on the first broken bone 3 and the second broken bone 4.

Specifically, the lower surface of the second bone fracture plate 2 is attached to the first broken bone 3 and the second broken bone 4, the lower surface of the second bone fracture plate 2 attached to the first broken bone 3 and the second broken bone 4 is provided with a plurality of limiting contact grooves 25, the number of the limiting contact grooves can be 2, 3, 4, 5 or 8, the two ends of the second bone fracture plate 2 are fixed to the first broken bone 3 and the second broken bone 4 respectively, and the upper surface of the second bone fracture plate is provided with a second resistance structure 21.

The first bone fracture plate 1 is arranged on the upper surface of the second bone fracture plate 2, two ends of the first bone fracture plate 1 are respectively connected with two ends of the second bone fracture plate 2 in an aligned mode and fixed on the first broken bone 3 and the second broken bone 4, and the lower surface of the first bone fracture plate 1 is provided with a first resistance structure 11. The first resistance structure 11 is matched with the second resistance structure 21, the first bone fracture plate 1 and the second bone fracture plate 2 can slide back to back, and stress can be buffered or the relative sliding movement can be dispersed when stress with certain strength is applied.

The first resistance structure 11 and the second resistance structure 21 are mutually matched and can play a role in stress dispersion, and the first resistance structure 11 and the second resistance structure 21 can be of various structures as long as the functions are realized. Specifically, as shown in fig. 4 and 5, the first resistance structure 11 and the second resistance structure 21 may be saw-tooth structures, and the saw-tooth structures may be symmetrical saw-tooth structures or asymmetrical saw-tooth structures. In order to achieve the technical effect of sliding between the first bone plate 1 and the second bone plate 2, the height of the sawteeth in the sawteeth structure can be 0.2mm-5mm, such as 0.5mm, 0.8mm, 1.0mm, 2.0mm, 3.5mm or 4.5 mm; as shown in fig. 6 and 7, the first resistance structure 11 may also be a protrusion and/or a groove structure, and correspondingly, the second resistance structure 21 is a groove and/or a protrusion structure, in order to achieve the technical effect that the first resistance structure 11 and the second resistance structure 21 can slide after being matched, the height of the protrusion or the depth of the groove may be 0.2mm to 5mm, such as 0.5mm, 0.8mm, 1.0mm, 2.0mm, 3.5mm, or 4.5mm, and the like, and those skilled in the art can design the corresponding height or depth according to the actual stress situation. As shown in fig. 8, the first resistance structure 11 and the second resistance structure 21 may be rough surface structures, and those skilled in the art can calculate the friction coefficient of the rough surfaces of the first bone plate 1 and the second bone plate 2 according to the actual stress condition of the combined bone plates.

As shown in fig. 9-11, the first bone plate 1 is a straight bone plate or a micro-arc bone plate, the edges of the two ends of the first bone plate 1 are respectively provided with a first kirschner wire hole 12, a first fixing hole is arranged between the first kirschner wire holes 12 of the two ends of the first bone plate 1, and the first fixing hole comprises a first locking hole 13, a first sliding hole 14 and optionally a first through hole 15. The part of the first bone plate 1 fixed on the first broken bone 3 is provided with a first locking hole 13, the part of the first bone plate 1 fixed on the second broken bone 4 is provided with a first sliding hole 14 and optionally a first through hole 15, and the first locking hole 13, the first sliding hole 14 and the first through hole 15 can be respectively provided with a plurality of holes, such as 3, 4, 5 or 6; the plurality of first locking holes 13, the plurality of first sliding holes 14 and the plurality of first through holes 15 may be symmetrically or asymmetrically distributed. The first locking hole 13 can be a common hole type structure and/or a locking pressurizing hole, and the first sliding hole 14 can be a spherical hole and/or an oblong hole; preferably, the part of the first bone plate 1 fixed on the second broken bone 4 is also provided with a first through hole 15, the first through hole 15 can be a locking hole and/or a sliding hole, and preferably, the first sliding hole 14 and the first through hole 15 are alternately arranged;

as shown in fig. 12-15, the second bone plate 2 is a straight bone plate or a micro-arc bone plate, the edges of the two ends of the second bone plate 2 are respectively provided with a second kirschner wire hole 22, a second fixing hole is arranged between the second kirschner wire holes 22 of the two ends of the second bone plate 2, and the second fixing hole comprises a second locking hole 23, a second sliding hole 24 and a third sliding hole 26; the part of the second bone plate 2 fixed on the first broken bone 3 is provided with a second sliding hole 24, and the part of the second bone plate 2 fixed on the second broken bone 4 is provided with a second locking hole 23 and a third sliding hole 26; the number of the second locking holes 23, the second sliding holes 24 and the third sliding holes 26 can be multiple, such as 3, 4, 5 or 6; the plurality of second sliding holes 24, the plurality of second locking holes 23 and the plurality of third sliding holes 26 are symmetrically or asymmetrically arranged; preferably, a plurality of third sliding holes 26 are alternately arranged with the second locking holes 23; the second locking hole 23 can be a common hole structure, and can also be a locking pressurizing hole, the second sliding hole 24 and the third sliding hole 26 can be oblong holes or spherical holes, preferably, the second sliding hole 24 is arranged between two or more second locking holes 23, and the number of the sliding holes can be set according to the requirement; when the first through-holes 15 are not provided, the second locking holes 23 may be provided as needed to lock the second bone plate 2 to the second fractured bone 4.

Preferably, when the first bone plate 1 is placed on the upper surface of the second bone plate 2, the first k-wire holes 12 and the second k-wire holes 22 are relatively overlapped, and meanwhile, the first fixing holes on the first bone plate 1 are overlapped with the second fixing holes on the second bone plate 2. Specifically, the first locking hole 13 is provided corresponding to the second sliding hole 24; the first sliding hole 14 and the third sliding hole 26 are arranged correspondingly; the first through hole 15 is provided corresponding to the second locking hole 23.

The internal fixation device further comprises a first locking member 51, a second locking member 52 and a third locking member 53, wherein the first locking member 51 passes through the first locking hole 13 and the second sliding hole 24 and is fixed on the first fractured bone 3, the second locking member 52 passes through the first sliding hole 14 and the third sliding hole 26 and is fixed on the second fractured bone 4, and the third locking member 53 passes through the second locking hole 23 and is fixed on the second fractured bone 4. The first locking member 51, the second locking member 52 and the third locking member 53 may be locking screws, and specifically, they may be cortical screws or cancellous screws, etc., and those skilled in the art can select a suitable screw type according to the needs.

Preferably, the first bone fracture plate 1 and the second bone fracture plate 2 of the internal fixing device have the same thickness and the same size, and the sum of the thicknesses of the first bone fracture plate 1 and the second bone fracture plate 2 is the thickness of the common bone fracture plate.

The working principle of the internal fixing device is as follows:

when the bone fracture plate is used, the first resistance structure 11 of the first bone fracture plate 1 is contacted with the second resistance structure 21 of the second bone fracture plate 2, the first resistance structure 11 and the second resistance structure 21 in the embodiment respectively adopt asymmetric sawtooth structures, and the inverse buckles of the asymmetric sawtooth structures are mutually matched to realize that the first bone fracture plate 1 and the second bone fracture plate 2 can only slide in one direction. The first and second k-

wire holes

12, 22 may be used to position the first and

second bone plates

1, 2 when first combined.

The first locking piece 51 fixes the first bone plate on the first broken bone 3 through the first bone plate 1 passing through the first locking hole and the second sliding hole; the second locking piece 52 enables the first bone plate and the second bone plate to be overlapped through the first sliding hole on the first bone plate 1 and the third sliding hole 26 on the second bone plate; the third locking member 53 fixes the second bone plate 2 to the second fractured bone 4 through the optional first through hole 15 and the second locking hole; or, one end of the second bone fracture plate 2 can be fixed on the second broken bone 4 through the third locking piece 53, then the first bone fracture plate 1 is overlapped on the second bone fracture plate 2, and the first locking piece 51 fixes the first bone fracture plate 1 on the first broken bone 3 through the first bone fracture plate 1 passing through the first locking hole 13 and the second sliding hole 24; the second locking member 52 allows the first bone plate 1 and the second bone plate 2 to be stacked together and fixed on the first fractured bone 3 and the second fractured bone 4 through the first sliding hole 14 of the first bone plate 1 and the third sliding hole 26 of the second bone plate 2. Therefore, one end of the first bone fracture plate 1 is fixed on the first broken bone 3, and the other end can slide; one part of the second bone fracture plate 2 is fixed on the second broken bone 4, and the other end can slide; the first bone plate 1 and the second bone plate 2 are engaged with each other by the first locking member 51 and the second locking member 52, so that the first resistance structure 11 and the second resistance structure 21 are engaged with each other. First coaptation board 1 and second coaptation board 2 cooperation are used, can realize the unilateral gliding motion through asymmetric sawtooth structure, and the stress concentration dispersion of screw hole department is the relative gliding motion between two bone plates, makes the fracture clearance inseparabler, realizes that main stress passes through human skeleton transmission, but the coaptation board bears partial stress, avoids coaptation board stress concentration and shelters from the phenomenon and takes place.

Specifically, during the rehabilitation of a patient, if a gap exists between the opposite ends of the fracture, when the bone at the fracture part is stressed and exceeds the sliding friction force of the bone fracture plate, the combined bone fracture plate disperses the stress at the screw hole into relative sliding force through the sliding function, and takes the human bone as a main stress carrier, and the stress shielding and concentration phenomena of the traditional bone plate are effectively avoided in the bone plate auxiliary stress mode; when the bone plates are not removed after fracture healing, when the bones are subjected to large stress, the bone plates slide relative to each other, the stress on the bones can be dispersed, and when the amount of bone compression reaches a limit, the bones can be subjected to certain stress.

Internal fixation device simple structure, convenient operation, through the relative cooperation of first coaptation board and second coaptation board, during the atress, can realize the relative slip of first coaptation board and second coaptation board to on transferring first coaptation board and the second coaptation board the stress that the broken bone received, and then changing into the relative motion of combination formula hone lamella, avoided stress concentration, the stress dispersion mode is unique, and better for traditional coaptation board stress dispersion effect.

First coaptation board and second coaptation board are coincide type from top to bottom in the internal fixation device, even when fracture department receives the power of perpendicular to diaphysis, it also can stably fix in fracture department, and can prevent the broken bone displacement, ensures that the coaptation board is fixed more firmly.

The thickness of the bone plate in the internal fixing device is not reduced, so the strength and the rigidity are consistent with those of the traditional bone plate, compared with the traditional single plate fixation, the impact of stress on the bone plate and the screw can be greatly reduced, and the fracture of the bone plate or the screw and the secondary fracture of the bone after the fracture is healed can be effectively avoided.

While one embodiment of the present invention has been described in detail, the description is only a preferred embodiment of the present invention and should not be taken as limiting the scope of the utility model. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.

Claims

1. The utility model provides an internal fixation device, includes the coaptation board, its characterized in that, the coaptation board is combination formula coaptation board, and it includes:

2. The internal fixation device as claimed in claim 1, wherein the overlapping surfaces of the first and second bone plates are provided with a first resistance structure; a second resistance structure is arranged on the surface of the second bone fracture plate overlapped with the first bone fracture plate; the first resistance structure and the second resistance structure can slide relatively after being matched.

3. The internal fixation device as claimed in claim 2, wherein the first or second resistance structure is one or a combination of at least two of a cooperating serration, protrusion and/or indentation structure or a roughened surface structure.

4. The internal fixation device as claimed in any one of claims 1 to 3, wherein the portion of the first bone plate fixed to the first bone fragment is provided with a first locking hole, and the portion of the first bone plate fixed to the second bone fragment is provided with a first sliding hole and optionally a first through hole;

5. The internal fixation device as claimed in claim 4, wherein the first through hole is selected from a slip hole and/or a lock hole.

6. The internal fixation device as recited in claim 4, wherein the first and second locking holes independently comprise locking compression holes.

7. The internal fixation device as recited in claim 4, wherein the first, second, and third slip holes independently comprise oblong holes.

8. The internal fixation device as claimed in any one of claims 1 to 3, wherein the first bone plate and the second bone plate are provided with Kirschner wire holes at both ends thereof.

9. The internal fixation device of any one of claims 1 to 3, wherein the first bone plate and the second bone plate are independently straight plates or micro-arc shaped plates.

10. The internal fixation device as claimed in any one of claims 1 to 3, wherein the bone-contacting surface of the modular bone plate is provided with contact-limiting grooves.