A cap-shaped prosthesis for cancellous bone reconstruction

Abstract

The present invention discloses a cancellous bone reconstruction cap-shaped prosthesis, comprising a cap-shaped body, wherein the body comprises a proximal and outward-turned edge portion, and a hollow cap portion extending from the inner periphery of the edge portion to the distal end; a porous structure is formed on the inner and outer surfaces of the hollow cap portion. The porous structure on the outer surface of the hollow cap portion of the present invention can achieve bone ingrowth, so that the reconstruction prosthesis can obtain a long-term biological fixation basis, improve the fixation strength of the long-term femoral reconstruction prosthesis, and reduce the risk of long-term periprosthetic fracture; a micro-interlock is formed between the inner surface of the hollow cap portion and the bone cement femoral prosthesis, thereby improving the initial fixation effect of the bone cement femoral stem and improving the success rate of bone cement femoral prosthesis revision; the edge of the body is tightly pressed against the femoral cortical fracture surface, so that stress is transmitted from the reconstruction prosthesis to the femur, preventing the bone cement femoral stem from sinking into the medullary cavity, and improving the overall reconstruction strength of the remaining femoral prosthesis.

Description

Technical Field

[0001] The invention relates to a magic cap-shaped prosthesis for reconstructing cancellous bone in the femoral medullary cavity, and belongs to the field of medical devices. Background Art

[0002] Hip replacement is an effective treatment for various end-stage hip arthritis. Hip revision surgery is a method for treating various failed hip replacements. Due to severe osteolysis caused by loosening or wear, stress shielding, periprosthetic infection, multiple surgical history, osteoporosis, iatrogenic bone defects caused by perforation or fenestration when removing the original prosthesis or residual bone cement, the femoral side is often faced with varying degrees of bone defects during hip revision surgery. The difficulty of reconstruction lies in the fact that there are often severe bone defects on the femoral side. At the same time, the femur is often combined with proximal anatomical remodeling during revision surgery, such as varus or retroversion remodeling. Therefore, the reconstruction strategy for femoral bone defects is determined based on the severity of the bone defect, the remaining bone volume and quality, and the changes in anatomical remodeling.

[0003] Many researchers have proposed classifications for femoral bone defects. The most widely used is the Paprosky classification, which considers three factors: the location of the bone defect (metaphysis or diaphysis), the remaining bone mass and support in the proximal femur, and the length of the diaphyseal isthmus available for distal fixation. This classification allows physicians to objectively assess femoral bone defects and select appropriate reconstructive methods based on the defect type. For severe femoral bone defects, particularly those with a trumpet-shaped, downwardly expanding medullary cavity or a stovepipe-shaped, expanded femoral medullary cavity, resulting in the absence of a diaphyseal isthmus for femoral stem fixation, conventional reconstructive methods include modular tapered titanium stems, impaction bone grafting, proximal femoral allograft bone-prosthesis composites, and proximal femoral replacement. However, modular tapered titanium stems are associated with a high incidence of early prosthesis subsidence, increasing the risk of intraoperative or postoperative fractures. These methods may also lead to complications such as stress concentration, stress shielding, insufficient effective fixation length, and insecure prosthesis fixation. Proximal femoral allograft-prosthesis complexes carry potential risks, including disease transmission, graft resorption and nonunion, aseptic loosening, periprosthetic fracture, and infection. Proximal femoral replacements have high dislocation rates and low long-term survival, making them suitable only as a stopgap measure for elderly, inactive patients with extensive and severe bone defects. While compression bone grafting theoretically has the potential to restore bone mass, it carries a high risk of intraoperative fracture and postoperative prosthesis subsidence. Furthermore, it carries disadvantages such as high surgical skill requirements, a time-consuming procedure, the risk of disease transmission, and graft resorption. Summary of the Invention

[0004] In response to the above problems, the purpose of the present invention is to provide a magic cap prosthesis for cancellous bone reconstruction for treating severe femoral bone defects, which is used to solve the problems of high failure rate of cement prostheses and poor reconstruction efficacy caused by the inability of bone cement to form sufficient micro-locking in the femoral medullary cavity in existing reconstruction methods.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a cancellous bone reconstruction cap-shaped prosthesis, comprising a cap-shaped body, the body comprising a brim located at the proximal end and turned outward, and a hollow cap body extending from the inner periphery of the brim to the distal end; a porous structure is formed on the inner and outer surfaces of the hollow cap body.

[0006] In some embodiments, a solid layer is provided between the inner surface and the outer surface of the hollow cap body, and the thickness of the solid layer is 1 to 10 mm.

[0007] In some embodiments, the cross-section of the inner surface of the hollow cap body is circular or elliptical, and the coronal section of the inner surface of the hollow cap body is rectangular or trapezoidal; the cross-section of the outer surface of the hollow cap body is circular or elliptical, and the coronal section of the outer surface of the hollow cap body is rectangular or trapezoidal.

[0008] In some embodiments, the hollow cap body is in the shape of a hollow cylinder, the inner diameter of the hollow cylinder is 0.8 cm to 6 cm, and the outer diameter is 1.2 cm to 6.4 cm;

[0009] Alternatively, when the hollow cap body is in the shape of a hollow cone, the taper is 0° to 30°, the inner diameter of the large end of the hollow cone is 0.8 cm to 6 cm, and the outer diameter of the large end is 1.2 cm to 6.4 cm.

[0010] In some embodiments, the height of the hollow cap body is 1 cm to 10 cm, and the thickness is 1 mm to 20 mm.

[0011] In some embodiments, porous structures are formed on the upper and lower surfaces of the edge portion, and the interior of the edge portion has a solid interlayer.

[0012] In some embodiments, the width of the edge portion is 2 mm to 15 mm, and the thickness is 2 mm to 30 mm.

[0013] In some embodiments, the porous structure is a trabecular-like porous structure with a pore size of 800 μm±200 μm and a porosity of 50% to 80%.

[0014] In some embodiments, the body is formed by 3D printing, and the material is titanium alloy or tantalum metal.

[0015] The present invention adopts the above technical solution, which has the following advantages: the cancellous bone reconstruction cap-shaped prosthesis provided by the present invention includes a main body composed of an edge and a hollow cap body, and a porous structure is formed on the inner and outer surfaces of the hollow cap body. The porous structure on the outer surface of the hollow cap body can obtain bone ingrowth, so that the reconstruction prosthesis can obtain a long-term biological fixation basis, improve the long-term fixation strength of the femoral-reconstruction prosthesis, and reduce the risk of long-term peri-prosthesis fracture; bone cement can penetrate into the porous structure on the inner surface of the hollow cap body, and bone cement forms a micro-lock between the inner surface of the hollow cap body and the bone cement femoral prosthesis, thereby improving the initial fixation effect of the bone cement femoral stem and improving the success rate of bone cement femoral prosthesis revision. The edge of the main body is tightly pressed on the bone surface of the femoral cortical fracture end, so that the stress is transmitted from the reconstruction prosthesis to the femur, preventing the bone cement femoral stem from sinking into the medullary cavity, and can improve the overall reconstruction strength of the remaining femur-prosthesis. The present invention effectively overcomes the defects of the prior art and improves the therapeutic effect of bone cement prosthesis reconstruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is another structural schematic diagram of the present invention;

[0018] Figure 3 It is a schematic diagram of the cross-sectional structure of the hollow cap body of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments. However, it should be understood that the accompanying drawings are provided only for a better understanding of the present invention and should not be construed as limiting the present invention.

[0020] like Figure 1 、 Figure 2 As shown, the present embodiment provides a cancellous bone reconstruction cap-shaped prosthesis, comprising a cap-shaped main body 1, the main body 1 comprising a brim 100 located at the proximal end and turned outward, and a hollow cap body 200 extending from the inner periphery of the brim 100 to the distal end; a porous structure is formed on the inner and outer surfaces of the hollow cap body 200.

[0021] When the reconstruction prosthesis provided by this embodiment is in use, the hollow cap body 200 of the main body 1 is driven into the femoral medullary cavity, and the outer surface of the hollow cap body 200 is tightly fitted with the inner wall of the femoral medullary cavity. The porous structure of the outer surface of the hollow cap body 200 can obtain bone ingrowth, so that the reconstruction prosthesis of the present invention can obtain a long-term biological fixation foundation, improve the long-term fixation strength of the femoral-reconstruction prosthesis, and reduce the risk of long-term peri-prosthesis fracture; the edge 100 of the main body 1 is tightly pressed on the bone surface of the femoral cortical end, so that the stress is transmitted from the reconstruction prosthesis to the femur, preventing the bone cement femoral stem from sinking into the medullary cavity, and can improve the overall reconstruction strength of the remaining femoral-prosthesis. The bone cement can penetrate into the porous structure on the inner surface of the hollow cap body 200, and the bone cement forms a micro-lock between the inner surface of the hollow cap body 200 and the bone cement femoral prosthesis, thereby improving the initial fixation effect of the bone cement femoral stem and improving the success rate of bone cement femoral prosthesis revision. Artificial bone or a coating material that promotes bone ingrowth can be sprayed into the porous structure on the outer surface of the hollow cap body 200 to stimulate bone integration into the porous surface; alternatively, the porous structure on the inner and outer surfaces of the hollow cap body 200 can be filled with antibiotics or antibacterial materials or coatings to prevent peri-prosthetic infection or promote bone ingrowth.

[0022] In the above embodiment, preferably, Figure 3 As shown, there is a solid layer between the inner surface and the outer surface of the hollow cap body 200. The thickness of the solid layer is 1 to 10 mm, which prevents bone cement from penetrating from the inner surface to the outer surface, thereby avoiding bone cement affecting the bone ingrowth potential of the outer surface.

[0023] In the above embodiment, preferably, the cross-section of the inner surface of the hollow cap body 200 may be circular or elliptical, and the coronal section of the inner surface of the hollow cap body 200 may be rectangular or trapezoidal; the cross-section of the outer surface of the hollow cap body 200 may be circular or elliptical, and the coronal section of the outer surface of the hollow cap body 200 may be rectangular or trapezoidal.

[0024] In the above embodiment, preferably, the hollow cap body 200 is in the shape of a hollow cylinder or a hollow cone. When the hollow cap body 200 is in the shape of a hollow cylinder, the inner diameter is 0.8cm~6cm, preferably 1cm~2.5cm, and the outer diameter is 1.2cm~6.4cm; when the hollow cap body 200 is in the shape of a hollow cone, the taper is 0°~30°, preferably 1°~15°, the inner diameter of the large end of the hollow cone is 0.8cm~6cm, preferably 1cm~2.5cm, the outer diameter of the large end is 1.2cm~6.4cm, preferably 1.4cm~3cm, the height of the hollow cap body 200 is 1cm~10cm, preferably 1.2cm~5cm; the thickness is 1mm~20mm, preferably 2mm~6mm.

[0025] In the above embodiment, preferably, porous structures are formed on the upper and lower surfaces of the edge portion 100 , and the interior of the edge portion 100 has a solid interlayer.

[0026] In the above embodiment, preferably, the porous structure is a trabecular-like porous structure with a pore size of 800 μm±200 μm and a porosity of 50%-80%.

[0027] In the above embodiment, preferably, the main body 1 can be formed by 3D printing, and the material can be titanium alloy or tantalum metal.

[0028] In the above embodiment, preferably, the width of the edge portion 100 is 2 mm to 15 mm, preferably 3 mm to 10 mm; the thickness of the edge portion 100 is 2 mm to 30 mm, preferably 2 mm to 10 mm.

[0029] The implantation process of the cancellous bone reconstruction cap prosthesis of the present invention is as follows:

[0030] 1) Obtain preoperative CT scan data of the patient's affected and unaffected hip joints. Use a computer to reconstruct the femoral morphology and select a cancellous bone cap with appropriate specifications. Alternatively, customize the cap by 3D printing based on the patient's specific medullary cavity structure.

[0031] 2) Preoperative planning based on the morphology of the cemented femoral prosthesis;

[0032] 3) The femur to be reconstructed is surgically exposed, the femoral medullary cavity is expanded, and the femoral medullary cavity is ground and reamed to the predetermined size;

[0033] 4) Using specialized instruments, the cancellous bone reconstruction cap is inserted into the femoral medullary cavity at the planned femoral osteotomy end, ensuring that it is press-fitted and fixed within the medullary cavity. The cap's edge is then tightly pressed against the femoral end.

[0034] 5) Bone cement is injected into the medullary cavity, allowing the bone cement to penetrate into the porous structure of the cap-shaped prosthesis, and then the bone cement femoral stem is implanted.

[0035] The present invention is described only with reference to the above embodiments, and the structure, location, and connection of each component are subject to change. Based on the technical solution of the present invention, any improvement or equivalent transformation of individual components based on the principles of the present invention should not be excluded from the scope of protection of the present invention.

Claims

1. A cap-shaped prosthesis for cancellous bone reconstruction, characterized in that: The invention comprises a cap-shaped body, the body comprising a proximal and outward-turned brim, and a hollow cap portion extending from the inner periphery of the brim to the distal end; a porous structure is formed on the inner and outer surfaces of the hollow cap portion; the porous structure on the outer surface of the hollow cap portion can achieve bone ingrowth, bone cement penetrates into the porous structure on the inner surface of the hollow cap portion, and the bone cement forms a micro-interlock between the inner surface of the hollow cap portion and the bone cement femoral prosthesis; a coating material that promotes bone ingrowth is sprayed into the porous structure on the outer surface of the hollow cap portion; or the porous structures on the inner and outer surfaces of the hollow cap portion are filled with an antibacterial material; A porous structure is formed on the upper and lower surfaces of the edge portion, and a solid interlayer is provided inside the edge portion; The width of the edge is 2mm to 15mm, and the thickness is 2mm to 30mm; The edge of the body is pressed tightly against the femoral cortical fracture surface, so that the stress is transferred from the reconstruction prosthesis to the femur, preventing the bone cement femoral stem from sinking into the medullary cavity, and improving the overall reconstruction strength of the remaining femur and prosthesis; A solid layer is provided between the inner surface and the outer surface of the hollow cap body, and the thickness of the solid layer is 1 to 10 mm.

2. The cancellous bone reconstruction cap-shaped prosthesis according to claim 1, characterized in that: The cross-section of the inner surface of the hollow cap body is circular or elliptical, and the coronal section of the inner surface of the hollow cap body is rectangular or trapezoidal; the cross-section of the outer surface of the hollow cap body is circular or elliptical, and the coronal section of the outer surface of the hollow cap body is rectangular or trapezoidal.

3. The cancellous bone reconstruction cap-shaped prosthesis according to claim 1, characterized in that: The hollow cap body is in the shape of a hollow cylinder, the inner diameter of the hollow cylinder is 0.8 cm to 6 cm, and the outer diameter is 1.2 cm to 6.4 cm; Alternatively, when the hollow cap body is in the shape of a hollow cone, the taper is 0° to 30°, the inner diameter of the large end of the hollow cone is 0.8 cm to 6 cm, and the outer diameter of the large end is 1.2 cm to 6.4 cm.

4. The cancellous bone reconstruction cap-shaped prosthesis according to any one of claims 1 to 3, characterized in that: The height of the hollow cap body is 1 cm to 10 cm, and the thickness is 1 mm to 20 mm.

5. The cancellous bone reconstruction cap-shaped prosthesis according to claim 1, characterized in that: The porous structure is a bone trabecular-like porous structure with a pore size of 800 μm±200 μm and a porosity of 50% to 80%.

6. The cancellous bone reconstruction cap-shaped prosthesis according to claim 1, characterized in that: The main body is formed by 3D printing, and the material is titanium alloy or tantalum metal.

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