A porous ring-shaped prosthesis for cancellous bone reconstruction

Abstract

The present invention discloses a cancellous bone reconstruction porous ring-shaped prosthesis, characterized in that it includes a hollow main body; the main body includes an inner surface in the shape of a hollow tube, an outer surface adapted to the shape of the femoral medullary cavity, an upper end surface located at the top, and a lower end surface located at the bottom, and the inner surface, outer surface, upper end surface and lower end surface of the main body are all formed with a porous structure. The porous structure on the outer surface of the main body of the present invention can enable the reconstruction prosthesis to obtain bone ingrowth, improve the long-term overall strength of the femur and the main body, reduce the risk of long-term periprosthetic fractures, and improve the long-term fixation effect of the reconstruction prosthesis; the porous structure on the inner surface of the main body can enable bone cement to form sufficient micro-interlocks between the inner surface of the main body and the bone cement femoral prosthesis, thereby improving the fixation effect of the cement prosthesis, overcoming the problem of high failure rate of cement prostheses in existing reconstruction methods, and improving the efficacy of revision surgery for patients with severe bone defects.

Description

Technical Field

[0001] The invention relates to a porous metal ring-shaped prosthesis for cancellous bone reconstruction, belonging 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 porous metal ring-shaped prosthesis for cancellous bone reconstruction for treating severe femoral bone defects, so that the bone cement can form sufficient micro-locks in the femoral medullary cavity, improve the fixation effect of the bone cement handle, and improve the overall reconstruction strength of the femur and prosthesis, overcome the high failure rate of cement prostheses in existing reconstruction methods, and improve the efficacy of revision surgery for patients with severe bone defects.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: a porous ring-shaped prosthesis for cancellous bone reconstruction, comprising a hollow main body; the main body comprises an inner surface in the shape of a hollow tube, an outer surface adapted to the morphology of the femoral medullary cavity, an upper end surface located at the top, and a lower end surface located at the bottom, and a porous structure is formed on the inner surface, outer surface, upper end surface and lower end surface of the main body.

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

[0007] In some embodiments, the porous structure is a trabecular-like structure, the pore size of the porous structure is 700 μm±300 μm, and the porosity is 50% to 80%.

[0008] In some embodiments, the main body is made of titanium alloy or tantalum metal and is formed by 3D printing.

[0009] In some embodiments, the coronal section of the inner surface is rectangular or trapezoidal, with the bottom side of the trapezoid being 1 cm to 6 cm long and the top side being 0.8 cm to 3 cm long; the cross section is circular or elliptical, with the circular diameter being 0.8 cm to 6 cm, the long axis of the ellipse being 1 cm to 6 cm, and the short axis being 0.5 cm to 3 cm.

[0010] In some embodiments, the cross section of the outer surface is circular or elliptical, the diameter of the circle is 1.2 cm to 6.4 cm, the long axis of the ellipse is 1.2 cm to 6.4 cm, and the short axis is 0.9 cm to 3.4 cm. The coronal section of the outer surface is rectangular or trapezoidal.

[0011] In some embodiments, the height of the main body is 1 cm to 10 cm, and the thickness of the main body is 1 mm to 20 mm.

[0012] The present invention adopts the above technical solution, which has the following advantages: the porous ring-shaped prosthesis for cancellous bone reconstruction provided by the present invention includes a main body, the main body includes an inner surface in a hollow tubular shape, an outer surface adapted to the morphology of the femoral medullary cavity, an upper end surface located at the top, and a lower end surface located at the bottom. A porous structure is formed on the inner surface, outer surface, upper end surface and lower end surface of the main body. The porous structure on the outer surface of the main body can enable the reconstructed prosthesis to obtain bone ingrowth, improve the long-term overall strength of the femur and the main body, reduce the risk of long-term peri-prosthesis fractures, and improve the long-term fixation effect of the reconstructed prosthesis; the porous structure on the inner surface of the main body can enable the bone cement to form sufficient micro-locks between the inner surface of the main body and the bone cement femoral prosthesis, thereby improving the fixation effect of the cement prosthesis, overcoming the problem of high failure rate of cement prostheses in existing reconstruction methods, and improving the efficacy of revision surgery for patients with severe bone defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the overall structure of the reconstruction prosthesis of the present invention;

[0014] Figure 2 is a schematic cross-sectional view of a reconstruction prosthesis of the present invention;

[0015] Figure 3 It is a schematic diagram of the structure of the present invention installed in the femoral medullary cavity. DETAILED DESCRIPTION

[0016] 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.

[0017] It should be noted that all directional indications in this embodiment (such as proximal end, distal end, front end, rear end, upper end, lower end, etc.) are only used to explain the relative position relationship, movement status, etc. of each component under the general operating posture, that is, the side close to the operator is called the proximal end or rear end, and the side away from the operator is called the distal end or front end; if the operating posture changes, the directional indication will also change accordingly.

[0018] like Figure 1 、 Figure 2 As shown, the present embodiment provides a porous ring-shaped prosthesis for cancellous bone reconstruction, comprising a hollow main body 10; the main body 10 comprises a hollow tubular inner surface 101, an outer surface 102 adapted to the morphology of the femoral medullary cavity, an upper end surface 103 at the top, and a lower end surface 104 at the bottom, and a porous structure is formed on the inner surface 101, the outer surface 102, the upper end surface 103 and the lower end surface 104 of the main body 10.

[0019] When the reconstructive prosthesis provided in this embodiment is used, the main body 10 is inserted into the femoral medullary cavity, and the outer surface 102 of the main body 10 is pressed tightly against the inner wall of the femoral medullary cavity. The porous structure on the outer surface 102 of the main body 10 can achieve bone ingrowth, so that the prosthesis obtains a long-term biological fixation foundation; the bone cement femoral prosthesis passes through the interior of the main body 10, and the bone cement can penetrate into the porous structure on the inner surface 101 of the main body 10. The bone cement forms a micro-lock between the inner surface 101 of the main body 10 and the bone cement femoral prosthesis, thereby improving the success rate of cement prosthesis revision. At the same time, artificial bone or a coating material that promotes bone ingrowth can be sprayed into the porous structure on the outer surface 102 of the main body 10, thereby stimulating bone integration into the porous surface. Alternatively, the porous structures on the inner surface 101 and the outer surface 102 are filled with antibiotics or antibacterial materials or coatings to prevent periprosthetic infection or promote bone ingrowth. It is understandable that the number of main body parts 10 inserted into the femoral medullary cavity is uncertain and needs to be determined according to the degree of femoral defect of the patient.

[0020] In the above embodiment, preferably, there is a solid layer 105 between the inner surface 101 and the outer surface 102 of the main body 10, and the thickness of the solid layer 105 is 1 to 10 mm, which prevents bone cement from penetrating from the inner surface 101 into the outer surface 102, thereby avoiding bone cement affecting the bone ingrowth potential of the outer surface 102.

[0021] In the above embodiment, preferably, the porous structure is a trabecular-like structure, the pore size of the porous structure is 700 μm±300 μm, and the porosity is 50%-80%.

[0022] In the above embodiment, preferably, the main body 10 is made of metal and can be formed by 3D printing, such as electron beam melting 3D printing process. The main body 100 can be made of titanium alloy or tantalum metal.

[0023] In the above embodiment, preferably, the coronal section of the inner surface 101 can be rectangular or trapezoidal, with the bottom side of the trapezoid being 1 cm to 6 cm long and the top side being 0.8 cm to 3 cm long; the cross section is circular or elliptical, with the circular diameter being 0.8 cm to 6 cm, preferably 1 cm to 2.5 cm, the major axis of the ellipse being 1 cm to 6 cm, and the minor axis being 0.5 cm to 3 cm.

[0024] In the above embodiment, preferably, the cross-section of the outer surface 102 can be circular or elliptical, the diameter of the circle is 1.2 cm to 6.4 cm, the long axis of the ellipse is 1.2 cm to 6.4 cm, and the short axis is 0.9 cm to 3.4 cm. The coronal section of the outer surface 102 can be rectangular or trapezoidal or other shapes to adapt to the morphology of the femoral medullary cavity.

[0025] In the above embodiment, preferably, the height of the main body 10 is 1 cm to 10 cm, preferably 1.2 cm to 4 cm, and the thickness of the main body 10 is 1 mm to 20 mm, preferably 2 mm to 6 mm.

[0026] like Figure 3 As shown, based on a porous ring-shaped prosthesis for cancellous bone reconstruction in any of the above embodiments, the present invention further provides a method for implanting a porous ring-shaped prosthesis for cancellous bone reconstruction, which comprises the following steps:

[0027] 1) Obtain preoperative hip joint examination data from both the affected and unaffected sides of the patient; reconstruct the femoral morphology using a computer and select a cancellous bone reconstructive porous ring prosthesis of appropriate specifications, or customize the cancellous bone reconstructive porous ring prosthesis through 3D printing based on the patient's specific medullary cavity structure;

[0028] 2) Preoperative planning based on the morphology of the cemented femoral prosthesis;

[0029] 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;

[0030] 4) Use specialized instruments to insert the cancellous bone reconstruction porous ring prosthesis into the femoral medullary cavity at the pre-operative planned position, allowing it to be press-fitted and fixed within the medullary cavity;

[0031] 5) Bone cement is injected into the medullary cavity to allow the bone cement to penetrate into the porous ring-shaped prosthesis, and then the bone cement femoral stem is implanted.

[0032] 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 porous ring-shaped prosthesis for cancellous bone reconstruction, characterized by: The device comprises a hollow main body; the main body comprises an inner surface in the shape of a hollow tube, an outer surface adapted to the shape of the femoral medullary cavity, an upper end surface at the top, and a lower end surface at the bottom, wherein the inner surface, outer surface, upper end surface, and lower end surface of the main body are all formed with a porous structure; A solid layer is provided between the inner surface and the outer surface of the main body, and the thickness of the solid layer is 1 to 10 mm, so as to prevent bone cement from penetrating from the inner surface to the outer surface, thereby preventing the bone cement from affecting the bone ingrowth potential of the outer surface; During use, the main body is injected into the femoral medullary cavity, and the outer surface of the main body is pressed tightly against the inner wall of the femoral medullary cavity. The porous structure on the outer surface of the main body can obtain bone ingrowth, so that the prosthesis obtains a long-term biological fixation foundation; the bone cement femoral prosthesis passes through the interior of the main body, and the bone cement can penetrate into the porous structure on the inner surface of the main body. The bone cement forms a micro-lock between the inner surface of the main body and the bone cement femoral prosthesis, thereby improving the success rate of cement prosthesis revision. At the same time, the porous structure on the outer surface of the main body is sprayed with a coating material that promotes bone ingrowth, thereby stimulating bone integration into the porous surface, or the porous structure on the inner and outer surfaces is filled with antibacterial material to promote bone ingrowth or prevent peri-prosthetic infection. The number of main bodies injected into the femoral medullary cavity is determined according to the degree of femoral defect.

2. The porous ring-shaped prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The porous structure is a trabecular-like structure, the pore size of the porous structure is 700 μm±300 μm, and the porosity is 50% to 80%.

3. The porous ring-shaped prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The main body is made of titanium alloy or tantalum metal and is formed by 3D printing.

4. The porous ring-shaped prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The coronal section of the inner surface is rectangular or trapezoidal, with the bottom side of the trapezoid being 1cm to 6cm long and the top side being 0.8cm to 3cm long; the cross section is circular or elliptical, with the circular diameter being 0.8cm to 6cm, the long axis of the elliptical being 1cm to 6cm, and the short axis being 0.5cm to 3cm.

5. The porous ring-shaped prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The cross section of the outer surface is circular or elliptical, the diameter of the circle is 1.2cm to 6.4cm, the major axis of the ellipse is 1.2cm to 6.4cm, and the minor axis is 0.9cm to 3.4cm. The coronal section of the outer surface is rectangular or trapezoidal.

6. The porous ring-shaped prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The height of the main body is 1 cm to 10 cm, and the thickness of the main body is 1 mm to 20 mm.

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