Internal fixation bone pad which gradually eliminates stress shielding

Abstract

The present application relates to an internal fixation bone pad which gradually eliminates stress shielding. The internal fixation bone pad comprises a bone pad body, the bone pad body comprises at least two vertically stacked pad plates (1), different pad plates (1) are made of degradable materials with different degradation times, a vertically penetrating fixing bolt hole (2) is arranged on the pad plates (1), and a fixing bolt is arranged in the fixing bolt hole (2). The degradation time of the bone pad is controlled in a segmented manner, the degradation times of the various pad plates forming the bone pad body being different, so that the looseness of the fixing structure changes from low to high, so as to achieve the effect of gradually increasing the stress borne by a fracture surface. The degradation time of the pad plate closest to a broken bone is the shortest, and the degradation time of the pad plate furthest away from the broken bone is the longest, which helps the pad plates to be absorbed.

Description

An internal fixation bone pad that gradually eliminates stress shielding Technical Field

[0001] The present invention relates to the technical field of medical devices, in particular to an internal fixation bone pad capable of gradually eliminating stress shielding. Background Art

[0002] Internal fixation with metal nail plates will produce stress shielding for the fracture ends, which not only weakens the stimulation of growth on the fracture ends, but also causes thinning of the cortical bone at the healing site, osteoporosis, and reduced strength, ultimately leading to the risk of nonunion or secondary fracture after the metal nail plate is removed.

[0003] To eliminate stress shielding, existing techniques use degradable, absorbable materials in the nail-plate fixation structure. After a period of strong fixation, the material degrades, causing the fixation structure to loosen, eliminating stress shielding. A bone pad is a spacer placed between the plate and the bone. The dotted bone pad not only relaxes the fixation structure after degradation, eliminating stress shielding, but also creates a gap between the plate and the bone during the strong fixation period, protecting the periosteum and maintaining nourishment and blood supply. However, bone pads made of a single degradable, absorbable material (including a blend of multiple components) have a single degradation and disintegration timeframe, making it difficult to achieve a gradual increase in stress on the fracture surface. This process is related to the looseness of the fixation structure after material degradation (i.e., the space left for the nail plate to move after the bone pad degrades). If the fixation structure suddenly loosens significantly and becomes ineffective, the newly healed bone will not have enough time to grow and strengthen, potentially exposing it to the risk of immediate refracture. Summary of the Invention

[0004] In response to the shortcomings of the above-mentioned existing production technology, the present application provides an internal fixation bone pad that gradually eliminates stress shielding, and controls the degradation time of the bone pad in segments, so that the looseness of the fixed structure can be changed from small to large, thereby achieving the effect of gradually increasing the stress on the fracture surface from small to large.

[0005] The technical solutions adopted in the present invention are as follows:

[0006] An internal fixation bone pad that gradually eliminates stress shielding includes a bone pad body, wherein the bone pad body includes at least two pads stacked up and down, and different pads are made of degradable materials with different degradation times; the pads are provided with fixing bolt holes that pass through from top to bottom, and fixing bolts are provided in the fixing bolt holes.

[0007] Furthermore, the degradation time of the backing plate closest to the broken bone is the shortest, and the degradation time of the backing plate farthest from the broken bone is the longest.

[0008] Furthermore, the upper and lower end surfaces of the pad are contact surfaces with the steel plate and the broken bone respectively, and the upper and lower contact surfaces of the pad can be matched and connected with the end surface of the steel plate and the end surface of the broken bone respectively.

[0009] Furthermore, a stacking positioning structure is provided on the pad, and at least two pads are positioned and stacked up and down through the stacking positioning structure.

[0010] Furthermore, the stacking positioning structure includes three positioning posts, which are fixed on one of the pads, and the other pads are sequentially mounted on the three positioning posts.

[0011] Furthermore, a wrapping layer is provided on the outer surface of the bone pad body.

[0012] Furthermore, the wrapping layer wraps the upper and lower end surfaces and the left and right end surfaces of the bone pad body.

[0013] Furthermore, bolt mounting holes are provided on the upper and lower end surfaces of the wrapping layer at positions corresponding to the fixing bolt holes, and the bolt mounting holes are used to pass the fixing bolts.

[0014] Furthermore, a plurality of liquid-permeable holes are provided on the surface of the wrapping layer, and the plurality of liquid-permeable holes are evenly distributed on the surface of the wrapping layer, and the liquid-permeable holes connect the inner and outer cavities of the wrapping layer.

[0015] Furthermore, a wrapping layer is provided on the outer surface of the bone pad body, and the wrapping layer wraps all end surfaces of the bone pad body.

[0016] The beneficial effects of the present invention are as follows:

[0017] The present invention controls the degradation time of the bone pad in sections, and the degradation time of each pad constituting the bone pad body is different, so that the looseness of the fixed structure can be changed from small to large, thereby achieving the effect of gradually increasing the stress on the fracture surface from small to large; the degradation time of the pad closest to the broken bone is the shortest, and the degradation time of the pad farthest from the broken bone is the longest, which is conducive to the absorption of the pads; a stacking positioning structure is provided between different pads, and different pads are positioned and stacked up and down through the stacking positioning structure; a wrapping layer is provided on the outer surface of the bone pad body, and the wrapping layer wraps the upper and lower end faces and the left and right end faces of the bone pad body to form a complete structure, ensuring that the pads constituting the bone pad body can be stacked together without scattering; a plurality of liquid-permeable holes are provided on the surface of the wrapping layer, and tissue fluid can penetrate into the interior of the bone pad body through the liquid-permeable holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a perspective view of a first embodiment of the present invention.

[0019] FIG2 is a schematic diagram of the stacking positioning structure of the first embodiment of the present invention.

[0020] FIG3 is a perspective view of a second embodiment of the present invention.

[0021] FIG4 is a perspective view of a third embodiment of the present invention.

[0022] Among them: 1. Base plate; 2. Fixing bolt hole; 3. Positioning column; 4. Wrapping layer; 5. Liquid permeable hole; 6. Bolt installation hole. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention will be described below with reference to the accompanying drawings. Example 1:

[0024] As shown in FIG1 , an internal fixation bone pad for gradually eliminating stress shielding includes a bone pad body, which includes at least two pads 1 stacked up and down. The number of pads 1 is related to the number of nodes in the stress shielding elimination process and can be set as needed.

[0025] Different pads 1 are made of degradable materials with different degradation times. The position of the pads 1 with different degradation times within the bone pad body does not affect the looseness of the pad body. However, to facilitate absorption, the pads 1 closer to the broken bone should degrade earlier. Therefore, the pads 1 closest to the broken bone will have the shortest degradation time, while the pads 1 furthest from the broken bone will have the longest degradation time.

[0026] The various types of biodegradable and absorbable biomaterials used in the pad 1 of this embodiment need to be able to maintain their strength for about 3-6 months, 6-8 months, or 8-12 months after being implanted into the human body, such as synthetic polymer materials such as PCL, PLA, and PPDO.

[0027] The backing plate 1 is provided with a fixing bolt hole 2 which passes through the backing plate 1 from top to bottom. A fixing bolt is provided in the fixing bolt hole 2. The fixing bolt fixes the plurality of backing plates 1 together between the steel plate and the broken bone.

[0028] The upper and lower end surfaces of the backing plate 1 are contact surfaces with the steel plate and the broken bone respectively. The upper and lower contact surfaces of the backing plate 1 can be matched and connected with the end surface of the steel plate and the end surface of the broken bone respectively.

[0029] As shown in Figures 1 and 2, a stacking positioning structure is provided on the backing plate 1, and at least two backing plates 1 are stacked vertically by the stacking positioning structure. The stacking positioning structure includes three positioning posts 3, which are fixed to one of the backing plates 1, and the other backing plates 1 are sequentially mounted on the three positioning posts 3. Example 2:

[0030] As shown in Figure 3, the difference from Example 1 is that a wrapping layer 4 is provided on the outer surface of the bone pad body, and the wrapping layer 4 wraps the upper and lower end faces and the left and right end faces of the bone pad body to form a complete structure, ensuring that the pads 1 constituting the bone pad body can be stacked together without scattering.

[0031] As shown in FIG3 , bolt mounting holes 6 are provided at positions corresponding to the fixing bolt holes 2 on the upper and lower end surfaces of the wrapping layer 4 , and the bolt mounting holes 6 are used to pass the fixing bolts.

[0032] As shown in Figure 3, the surface of the wrapping layer 4 is provided with a plurality of liquid-permeable holes 5, which are evenly distributed on the surface of the wrapping layer 4. The liquid-permeable holes 5 connect the inner and outer cavities of the wrapping layer 4, and tissue fluid can penetrate into the interior of the bone pad body through the liquid-permeable holes 5.

[0033] The upper end surface structure of the wrapping layer 4 is consistent with the contact end surface of the steel plate, and the lower end surface structure of the wrapping layer 4 is consistent with the end surface of the broken bone. Example 3:

[0034] As shown in FIG4 , the difference from the second embodiment is that the wrapping layer 4 wraps all the end faces of the bone pad body to form a complete structure, ensuring that the pads 1 constituting the bone pad body can be stacked together without falling apart.

[0035] The working principle of the present invention is as follows: the present invention uses biomaterials with different degradation and disintegration times to make pads 1 corresponding to the looseness of the fixed structure, and stacks the pads 1 in a number corresponding to the number of nodes in the stress shielding elimination process and fixes them into a bone pad body. In this way, at each node in the stress shielding elimination process, a corresponding pad 1 made of degradable absorbent material degrades and disintegrates, generating and accumulating space, which is converted into a change in the looseness of the fixed structure, thereby realizing the gradual elimination of stress shielding in line with the progress of fracture healing.

[0036] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any modifications may be made within the scope of protection of the present invention.

Claims

1. An internal fixation bone pad for gradually eliminating stress shielding, comprising a bone pad body, characterized in that: The bone pad body comprises at least two pads (1) stacked up and down, and the different pads (1) are made of degradable materials with different degradation times; the pads (1) are provided with fixing bolt holes (2) that penetrate up and down, and fixing bolts are arranged in the fixing bolt holes (2).

2. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 1, characterized in that: The degradation time of the backing plate (1) closest to the broken bone is the shortest, and the degradation time of the backing plate (1) farthest from the broken bone is the longest.

3. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 1, characterized in that: The upper and lower end surfaces of the pad (1) are contact surfaces with the steel plate and the broken bone respectively. The upper and lower contact surfaces of the pad (1) can be matched and connected with the end surface of the steel plate and the end surface of the broken bone respectively.

4. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 1, characterized in that: A stacking positioning structure is provided on the pad (1), and at least two pads (1) are stacked up and down by means of the stacking positioning structure.

5. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 4, characterized in that: The stacking positioning structure comprises three positioning columns (3), the three positioning columns (3) being fixed on one of the pads (1), and the other pads (1) being sequentially sleeved on the three positioning columns (3).

6. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 1, characterized in that: A wrapping layer (4) is provided on the outer surface of the bone pad body.

7. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 6, characterized in that: The wrapping layer (4) wraps the upper and lower end surfaces and the left and right end surfaces of the bone pad body.

8. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 7, characterized in that: Bolt mounting holes (6) are provided at positions on the upper and lower end surfaces of the wrapping layer (4) corresponding to the fixing bolt holes (2), and the bolt mounting holes (6) are used to pass the fixing bolts.

9. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 8, characterized in that: A plurality of liquid-permeable holes (5) are arranged on the surface of the wrapping layer (4), the plurality of liquid-permeable holes (5) are evenly distributed on the surface of the wrapping layer (4), and the liquid-permeable holes (5) connect the inner and outer cavities of the wrapping layer (4).

10. The internal fixation bone pad for gradually eliminating stress shielding as claimed in claim 6, characterized in that: The wrapping layer (4) wraps all end surfaces of the bone pad body.

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