Bone nail and connecting assembly for converting long bone fracture from strong fixation to biological fixation
By designing degradable bone nails and limiting structures, the problem of fracture end displacement caused by strong fixation in long bone fractures is solved, and the transformation from strong fixation to biological fixation is achieved, promoting fracture healing and avoiding stress occlusion.
Patent Information
- Application Number
- CN202510204376.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-24
- Publication Date
- 2025-07-04
AI Technical Summary
In the treatment of medium- and long bone fractures in the prior art, strong fixation leads to dislocation of the fracture end, resulting in biomechanical instability and affecting the postoperative healing effect.
A bone nail is designed, including a nail cap and a screw body. The nail cap is made of a degradable material or is equipped with a degradable coating on the periphery. It combines the design of a limiting table and limiting slot to prevent the nail cap from rotating and is used in combination with the bone junction plate to achieve transformation from strong fixation to biofixation.
Through the use of degradable materials and limiting structure, secondary surgery is avoided, fracture healing is promoted, fracture end displacement and stress occlusion are prevented, and fracture fixation effect is provided.
Smart Images
Figure CN120241215A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of medical devices, and specifically, to a bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation and a connection assembly including the bone nail. Background Art
[0002] Long bone fractures are common bone injuries in clinical practice. In clinical treatment, rigid internal fixation is often used to treat long bone fractures. The AO (Association for the Study of Internal Fixation) emphasizes that the main goal of surgical treatment is to provide an initial stability for fractures by providing safe open reduction and rigid internal fixation, which allows early, active and painless movement of the affected limb and can avoid early joint stiffness. However, in the late stage of fracture healing, osteoporosis and secondary fractures may occur due to stress shielding.
[0003] The core of the BO (Biological Osteosynthesis) is to perform reduction at a position far from the fracture ends, protect the soft tissues at the fracture site, and not deliberately pursue anatomical reduction of the fracture (except for intra-articular fractures). Although the BO fracture fixation uses internal fixation devices with low elastic modulus and reduces the contact area between the internal fixation device and the bone cortex, etc., to protect the blood supply of the fracture site, these improvements sacrifice the initial stability of fracture fixation. Therefore, it has become a challenge to design a set of bone plate systems that are rigidly fixed in the early stage and transform into biological fixation as the fracture heals.
[0004] Therefore, when currently using rigid mechanical fixation for broken bones, it is still difficult to solve the problem of fracture end displacement during fractures, resulting in biomechanical instability and affecting the postoperative healing effect. Therefore, a more reasonable technical solution still needs to be proposed to solve the current technical problems. Summary of the Invention
[0005] The purpose of the present invention is to provide a bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation and a connection assembly including the bone nail, so as to solve the problems of fracture end displacement during fractures, resulting in biomechanical instability and affecting the postoperative healing effect.
[0006] To achieve the above purpose, the present invention provides a bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation, including a nail cap for connecting a bone plate and a screw body for connecting the distal cortical bone of the fracture site to be fixed.
[0007] One end of the screw body is provided with a first external thread, the other end of the screw body is provided with a limiting platform, the nail cap is provided with a limiting groove adapted to the limiting platform, and the nail cap is sleeved on the limiting platform; the cross-sectional shape of the limiting platform is other than circular to prevent the nail cap from rotating relative to the axis line of the screw body.
[0008] Wherein, only the nail cap of the bone nail is made of a degradable material; or, only a degradable coating is provided on the outer periphery of the first external thread in the bone nail.
[0009] In a possible design, the transverse cross-section of the limiting platform is a regular hexagon.
[0010] In a possible design, along the direction away from the nail cap, the side length of the regular hexagon gradually becomes smaller.
[0011] In a possible design, a second external thread is provided on the outer periphery of the nail cap.
[0012] In a possible design, the degradable material is a bio-metal or a bioceramic.
[0013] A connecting assembly for realizing the transformation of the rigid fixation of a long bone fracture into a biological fixation, comprising a bone plate and bone nails, wherein a plurality of the bone nails are provided and connected to the bone plate.
[0014] In a possible design, the bone nails are arranged at intervals along the length direction of the bone plate.
[0015] The screw body is the main part of the bone nail and can connect and fix the distal cortical bone of the fracture site to be fixed. One end of the screw body is provided with a first external thread, which can be firmly embedded in the bone through the first external thread to provide a stable fixation effect. The other end of the screw body is provided with a limiting platform, which can increase the connection stability between the screw body and the nail cap and also prevent the rotation of the nail cap through its specific shape. The nail cap is used to connect the bone plate and is provided with a limiting groove adapted to the limiting platform, so that the nail cap can be stably sleeved on the limiting platform, thereby making the connection between the bone nail and the bone plate more firm and not easy to loosen.
[0016] Part of the structure of the bone nail can be made of a degradable material, so that it can gradually degrade and be finally absorbed in the human body, thus avoiding the risk of a second operation to remove the implant in the future. The selection of the degradable material should be based on factors such as its biocompatibility, mechanical properties, and degradation rate, and be flexibly selected according to the actual bone fracture situation of the patient.
[0017] It should be noted that the cross-sectional shape of the limiting platform is other shapes (such as polygons, ellipses, etc.) other than a circle, which can prevent the nail cap from rotating relative to the axis line of the screw body. After the bone nail is implanted into the body, the nail cap will not rotate relative to the screw body, thereby ensuring the connection relationship between the bone plate and the screw body and further ensuring the fixation effect. Thus, the relative rotation between the screw body and the nail cap is avoided, and the stability and fixation effect of the bone nail are ensured.
[0018] This bone nail is used in combination with a traditional bone plate for the recovery of long bone fractures. During the application process, the bone plate is first attached to the broken bone, and then multiple bone nails are used to connect to different broken bones respectively, thereby connecting the broken bones. Among them, in the initial stage, it is a rigid mechanical fixation, and the bone plate and the fracture site bear the force together, which can effectively prevent the displacement of the fracture ends and at the same time allow the patient to exercise early; in the later stage, as the nail cap gradually degrades, it is transformed into a biological fixation, and the fracture site bears the force, and the stimulation of the fracture ends gradually increases, which can effectively prevent the occurrence of secondary fractures and stress shielding phenomena.
[0019] Through the above technical solution, the transition repair of long bone fractures from mechanical fixation (AO) to biological fixation (BO) can be achieved. The mechanical fixation (AO) involved is an existing bone repair method. Based on the cooperation of bone nails and bone plates, it can provide good reliability and repair performance, and the repair instruments supporting the mechanical fixation (AO) can be modified to implement the improved scheme of this design without much improvement. When applied to the broken bone, it not only has good biocompatibility and degradability, but also can avoid the stress shielding effect, thereby promoting the healing of the broken bone.
[0020] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. Brief Description of the Drawings
[0021] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:
[0022] Figure 1 is a schematic structural diagram of the bone nail provided by the present invention for realizing the transformation of long bone fractures from rigid fixation to biological fixation in one embodiment. In this scheme, only the nail cap of the bone nail is made of a degradable material;
[0023] Figure 2 is Figure 1 a schematic structural diagram of the nail cap in
[0024] Figure 3 is Figure 1 a schematic structural diagram of the nail body in
[0025] Figure 4 is a schematic structural diagram of the bone nail provided by the present invention for realizing the transformation of long bone fractures from rigid fixation to biological fixation in another embodiment. Among them, Figure 4 different from the Figure 1 scheme, for example, the shape of the nail cap is different from the nail cap shown in Figure 1 ; and in this scheme, only the first external thread of the bone nail is plated with a degradable coating; Figure 4 The bone nail shown in
[0026] Figure 5 It is a usage state diagram of a connection component provided by the present invention for realizing the conversion of rigid fixation of long bone fractures into biological fixation;
[0027] Figure 6 It is the change of force conduction during the fracture recovery process of the connection component provided by the present invention for realizing the conversion of rigid fixation of long bone fractures into biological fixation.
[0028] Explanation of reference numerals
[0029] 1 - nail cap, 2 - screw body, 3 - limit groove, 4 - second external thread, 5 - first external thread, 6 - limit platform, 7 - fractured bone, 8 - bone plate, 9 - degradable coating. Specific embodiments
[0030] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.
[0031] According to the specific embodiments of the present disclosure, a bone nail for realizing the conversion of rigid fixation of long bone fractures into biological fixation is provided. It is mainly applied to long bone fractures and is used in cooperation with a bone plate, which can reduce stress shielding and promote the recovery of the fracture site. Among them, Figures 1 to 6 One specific embodiment is shown.
[0032] Referring to Figures 1 to 6 As shown, the bone nail for realizing the conversion of rigid fixation of long bone fractures into biological fixation includes a nail cap 1 for connecting the bone plate 8 and a screw body 2 for connecting the distal cortical bone of the fracture site to be fixed; one end of the screw body 2 is provided with a first external thread 5, the other end of the screw body 2 is provided with a limit platform 6, and the nail cap 1 is provided with a limit groove 3 adapted to the limit platform 6, and the nail cap 1 is sleeved on the limit platform 6; the cross-sectional shape of the limit platform 6 is other than circular to prevent the nail cap 1 from rotating relative to the axis line of the screw body 2. Among them, only the nail cap in this bone nail is made of a degradable material; or, only the outer periphery of the first external thread in this bone nail is provided with a degradable coating.
[0033] The screw body 2 is the main part of the bone nail and can connect and fix the distal cortical bone of the fracture site to be fixed. One end of the screw body 2 is provided with a first external thread 5, which is firmly embedded in the bone through the first external thread 5 to provide a stable fixation effect. The other end of the screw body 2 is provided with a limit platform 6, which can increase the connection stability between the screw body 2 and the nail cap 1 and also prevent the rotation of the nail cap 1 through its specific shape. The nail cap 1 is used to connect the bone plate 8 and is provided with a limit groove 3 adapted to the limit platform 6, so that the nail cap 1 can be stably sleeved on the limit platform 6, thereby making the connection between the bone nail and the bone plate 8 more firm and not easy to loosen.
[0034] In one embodiment, only the nail head of the bone nail is made of a degradable material. In this way, the nail head can gradually degrade in the human body and ultimately be absorbed, thus avoiding the risk of a second surgery to remove the implant in the future. The choice of the degradable material should be based on factors such as its biocompatibility, mechanical properties, and degradation rate.
[0035] In another embodiment, only the first external thread 5 of the bone nail is coated with a degradable coating 9. The introduction of the degradable coating 9 makes the bone nail have better biocompatibility after being implanted into the human body. It can be gradually absorbed and metabolized by human tissues, thereby reducing the irritation and inflammatory response to the surrounding tissues. In addition, the degradable coating 9 can also improve the interfacial relationship between the bone nail and the bone tissue. Before the coating degrades, it can provide a lubricating and protective layer to reduce the friction and damage between the bone nail and the bone tissue. As the coating degrades, the fixation between the bone nail and the bone becomes loose, converting from strong mechanical fixation to biological fixation.
[0036] Furthermore, the degradable coating 9 can also adjust the mechanical properties of the bone nail. By controlling the material and thickness of the coating, the strength and stiffness of the bone nail in the initial stage of implantation can be adjusted to meet different treatment requirements, which helps to improve the surgical effect and reduce the risk of the bone nail breaking or loosening during use. In this case, it can be selected whether to use it in combination with a bone plate according to the actual usage requirements. That is, the bone nail can be fixed alone or in combination with a bone plate.
[0037] It should be noted that the cross-sectional shape of the limiting platform 6 is other shapes than a circle (such as a polygon, an ellipse, etc.), which can prevent the nail head 1 from rotating relative to the axis line of the screw body 2. After the bone nail is implanted into the body, the nail head 1 remains fixed relative to the screw body 2 and does not rotate, thereby ensuring the stable connection relationship between the bone plate 8 and the screw body 2 and ensuring the final fixation effect. In this way, the relative rotation between the screw body 2 and the nail head 1 is avoided, ensuring the stability and fixation effect of the bone nail.
[0038] This bone nail is used in combination with a traditional bone plate 8 for the recovery of long bone fractures. During the application process, first, the bone plate 8 is attached to the fractured bone 7, and then multiple bone nails are used to connect to different fractured bones 7 respectively, thereby connecting the fractured bones 7. Among them, in the initial stage, it is strong mechanical fixation, and the bone plate 8 and the fracture site bear the force together, which can effectively prevent the displacement of the fracture end and at the same time allow the patient to move early; in the later stage, as the nail head 1 gradually degrades, it is converted into biological fixation, and the fracture site bears the force, and the stimulation of the fracture end gradually increases, which can effectively prevent the occurrence of secondary fractures and stress shielding phenomena.
[0039] Through the above technical solution, the transitional repair of long bone fractures from mechanical fixation (AO) to biological fixation (BO) can be achieved. The mechanical fixation (AO) involved is an existing bone repair method, which can provide good reliability and repair performance based on the cooperation of bone nails and bone plates, and the repair instruments supporting the mechanical fixation (AO) can implement the improved scheme of this design without much modification. When applied to the broken bone, it not only has good biocompatibility and degradability, but also can avoid the stress shielding effect, thus promoting the healing of the broken bone.
[0040] In an embodiment provided by the present disclosure, the transverse section of the limiting platform 6 is a regular hexagon, and the limiting groove 3 is formed into a structure adapted to the hexagonal limiting platform 6. Thus, the relative rotation between the screw body 2 and the nail cap 1 is avoided, ensuring the stability and fixation effect of the bone nail.
[0041] Specifically, the regular hexagon structure has six equal-length sides and six equal-sized angles. This symmetry enables it to provide stable support in multiple directions. When the limiting groove 3 of the nail cap 1 cooperates with the regular hexagonal limiting platform 6 of the screw body 2, multiple stable contact points will be formed between them. These contact points can not only effectively prevent rotation but also provide sufficient connection strength to ensure that the bone nail remains stable under various stresses. Thus, the loosening or rotation of the bone nail after implantation is avoided, the displacement of the fracture site is prevented, and the healing of the fracture is guaranteed.
[0042] Specifically, along the direction away from the nail cap 1, the side length of the regular hexagon gradually decreases. Due to the gradually decreasing side length, when the screw body 2 and the nail cap 1 cooperate, a tapered locking structure can be formed to prevent the relative rotation between the screw body 2 and the nail cap 1. In addition, the design of the gradually decreasing side length also causes a slight deformation of the contact surface between the screw body 2 and the nail cap 1 during the rotation fixation process, thereby increasing the friction between the two, which can further improve the stability of the bone nail and reduce the risk of its loosening during use.
[0043] In an embodiment provided by the present disclosure, the outer periphery of the nail cap 1 is provided with a second external thread 4, which can facilitate the cooperation of the nail cap 1 with the threaded hole provided on the bone plate 8, thereby providing mechanical locking for the connection between the nail cap 1 and the bone plate 8. When the nail cap 1 is screwed into the threaded hole of the bone plate 8, the interaction between the threads will generate a frictional force, which can effectively prevent the relative movement between the bone nail and the bone plate 8, so that the bone nail can be stably fixed on the bone plate 8.
[0044] In an embodiment provided by the present disclosure, the degradable material is bio-metal or bioceramic.
[0045] As a biodegradable material, biometal can gradually decompose in the human body environment and be absorbed or excreted by the human body, while having good biocompatibility with surrounding tissues. Specifically, the biometal can be configured as a magnesium alloy, an iron-based alloy, etc. By setting it in this way, not only can the biocompatibility of the bone nail be improved, reducing the inflammatory reaction after implantation, but it can also gradually degrade as the bone nail is implanted and the bone tissue grows, eliminating the need for a second operation to remove it.
[0046] As a biodegradable material, bioceramics also have excellent biocompatibility and bioactivity, can form chemical bonds with bone tissue, and promote the growth and repair of bone tissue.
[0047] According to the second aspect of the present disclosure, a connection component for realizing the conversion of rigid fixation of a long bone fracture into biological fixation is provided.
[0048] The connection component includes a bone plate 8 and bone nails. The bone nails are configured as multiple and are connected to the bone plate 8. The bone plate 8 is used to fix the fracture site, and can help the bone realign and heal. The threaded holes on the bone plate 8 can be connected to the bone nails, thereby fixing the bone plate 8 at the fracture site.
[0049] During the operation, first place the bone plate 8 at the fracture site to ensure it fits closely with the bone. Then, use the bone nails to fix the bone plate 8 to the bone. The bone nails are connected to the bone plate 8 by screwing into the threaded holes on the bone plate 8. This connection method is not only firm and reliable, but also can be adjusted as needed to ensure the best fixation of the fracture site. Through the close cooperation of the bone nails and the bone plate 8, it can be ensured that the fracture site is stably fixed, reducing the risk of displacement and deformation.
[0050] After the connection component is applied to the broken bone 7, it is initially in rigid mechanical fixation, with the bone plate 8 and the fracture site jointly bearing the force, which can effectively prevent the displacement of the fracture ends, and at the same time allow the patient to exercise early; later, as the nail cap 1 gradually degrades, it is converted into biological fixation, with the fracture site bearing the force, and the stimulation of the fracture ends gradually increases, which can effectively prevent the occurrence of secondary fractures and stress shielding phenomena.
[0051] In the present disclosure, the bone nails are arranged at intervals along the length direction of the bone plate 8, which can ensure uniform fixation of the fracture site and reduce the risk of displacement or deformation caused by uneven fixation. Even when some bone nails are subjected to external pressure or impact, other bone nails can still provide sufficient support. In this way, it can adapt to fracture sites of different lengths and shapes.
[0052] The biodegradable material includes but is not limited to biodegradable metal materials for biomedical use, biodegradable bioceramic materials, and polymer materials.
[0053] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.
Claims
1. A bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation, characterized in that, It includes a nail head for connecting an osteosynthesis plate and a screw body for connecting the distal cortical bone of the fracture site to be fixed. One end of the screw body is provided with a first external thread, the other end of the screw body is provided with a limiting platform, the nail head is provided with a limiting groove adapted to the limiting platform, and the nail head is sleeved on the limiting platform; the cross-sectional shape of the limiting platform is other than circular to prevent the nail head from rotating relative to the axis line of the screw body. Among them, only the nail head of the bone nail is made of a degradable material; or, only a degradable coating is provided on the outer periphery of the first external thread in the bone nail.
2. The bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation according to claim 1, characterized in that, The lateral cross-section of the limiting platform is a regular hexagon.
3. The bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation according to claim 2, characterized in that, Along the direction away from the nail head, the side length of the regular hexagon gradually becomes smaller.
4. The bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation according to claim 1, characterized in that, The outer periphery of the nail head is provided with a second external thread.
5. The bone nail for realizing the transformation of rigid fixation of long bone fractures into biological fixation according to claim 1, characterized in that, The degradable material is a bio-metal or a bioceramic.
6. A connecting component for realizing the transformation of rigid fixation of long bone fractures into biological fixation, characterized in that, It includes an osteosynthesis plate and the bone nail according to any one of claims 1 to 5, and a plurality of the bone nails are arranged and connected to the osteosynthesis plate.
7. The connecting component for realizing the transformation of rigid fixation of long bone fractures into biological fixation according to claim 6, characterized in that, The bone nails are arranged at intervals along the length direction of the osteosynthesis plate.