An expandable prosthesis for cancellous bone reconstruction

Abstract

The present invention discloses an expandable prosthesis for cancellous bone reconstruction, comprising a ring-shaped main body and a one-way expansion component; a gap is formed on the side wall of the main body; the one-way expansion component comprises a first expansion piece and a second expansion piece located inside the main body and arranged on both sides of the gap, and a one-way limiting structure is arranged between the first expansion piece and the second expansion piece and limits the relative movement of the two to relative back movement; the one-way expansion component of the present invention enables the ring-shaped main body to be expanded and expanded in a one-way manner, and the outer surface of the main body is pressed and matched with the medullary cavity, so that the prosthesis is press-fitted and fixed in the femoral medullary cavity, and bone ingrowth can be obtained in the long term; a porous structure is formed on the surface of the main body, so that the reconstruction prosthesis can obtain a long-term biological fixation foundation, improve the fixation strength of the femoral reconstruction prosthesis in the long term, reduce the risk of periprosthetic fracture in the long term, improve the initial fixation effect of the bone cement femoral stem, and improve the success rate of the revision of the bone cement femoral prosthesis.

Description

Technical Field

[0001] The invention relates to an expandable metal ring-shaped prosthesis for cancellous bone reconstruction, belonging to the field of medical instruments. Background Art

[0002] Artificial hip replacement is an effective means of treating various end-stage hip arthritis. Artificial hip revision surgery is a method for treating various failed artificial 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 artificial 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 of femoral bone defects is determined based on the severity of the bone defect, the remaining bone mass and quality, and the changes in anatomical remodeling.

[0003] Many scholars have proposed classifications for femoral bone defects, among which the most widely used classification is the Paprosky classification, which takes into account three factors: the site of bone defect (metaphysis or diaphysis), the remaining bone volume and support of the proximal femur, and the length of the isthmus of the diaphysis that can be used for distal fixation. Based on this classification, doctors can objectively evaluate femoral bone defects and choose appropriate reconstruction methods based on the defect classification. For severe femoral bone defects, especially those in which the medullary cavity forms a trumpet-shaped structure that expands downward or the femoral medullary cavity expands and expands into a stovepipe shape, resulting in a bone defect with no isthmus of the diaphysis for femoral stem fixation, traditional reconstruction methods such as combined conical ridged titanium stems, impaction bone grafting, proximal femoral allograft bone-prosthesis complexes, and proximal femoral replacement can be selected. The incidence of early prosthesis subsidence after combined conical ridged titanium stems is high, and the risk of intraoperative or postoperative fractures is increased. It may also lead to a series of complications such as stress concentration, stress shielding, insufficient effective fixation length, and unreliable prosthesis fixation. Proximal femoral allograft-prosthesis complexes have potential risks such as disease transmission, graft bone absorption and nonunion, aseptic loosening, periprosthetic fracture and infection. Proximal femoral replacement has a high dislocation rate and a low long-term survival rate, and is only suitable as a stopgap measure for elderly patients with low activity and a large number of severe bone defects. Although compression bone grafting has the potential to rebuild the patient's bone mass in theory, it has a high risk of intraoperative fracture and postoperative prosthesis sinking, and has disadvantages such as high surgical technical requirements, time-consuming, disease transmission risk, and bone graft absorption. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an expandable metal ring prosthesis for cancellous bone reconstruction, which overcomes the problems existing in the prior art, enhances the micro-locking ability of bone cement in the hardened medullary cavity, and improves the stability of the bone cement prosthesis.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solutions: an expandable prosthesis for cancellous bone reconstruction, comprising a ring-shaped main body and a unidirectional expansion component; a gap is formed on the side wall of the main body; the unidirectional expansion component comprises a first expansion member and a second expansion member located inside the main body and arranged on both sides of the gap, and a unidirectional limiting structure is formed between the first expansion member and the second expansion member and limits the relative movement between the two to relative back movement.

[0006] In some embodiments, the first expansion member and the second expansion member are respectively a first one-way tooth and a second one-way tooth, the first one-way tooth is formed on the main body on one side of the gap, and each tooth tip on the first one-way tooth points to the gap, the second one-way tooth is fixed on the main body on the other side of the gap, and each tooth tip on the second one-way tooth faces away from the gap, and the teeth on the second one-way tooth mesh with the teeth on the first one-way tooth to form a one-way limiting structure.

[0007] In some embodiments, the main body includes a first arc-shaped body and a second arc-shaped body hinged to each other, and the gap is formed between side end surfaces of the first arc-shaped body and the second arc-shaped body.

[0008] In some embodiments, a porous structure is formed on the surface of the body; and the interior of the body has a solid layer.

[0009] 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%.

[0010] In some embodiments, the inner surface of the body is hollow tubular with an inner diameter of 0.8 cm to 6 cm, the cross-section of the outer surface of the body is circular or elliptical, the coronal section of the body is rectangular or trapezoidal, the height of the body is 1 cm to 10 cm, and the thickness is 1 mm to 20 mm.

[0011] In some embodiments, the main body is formed by 3D printing, and the material is titanium alloy or tantalum metal.

[0012] The present invention adopts the above technical scheme, which has the following advantages: the cancellous bone reconstruction expandable prosthesis provided by the present invention includes a ring-shaped main body and a one-way expansion component; the side wall of the main body is formed with a gap; the one-way expansion component includes a first expansion piece, a second expansion piece, and a one-way limiting structure arranged between the first expansion piece and the second expansion piece and limiting the relative movement of the two to relative back movement; the one-way expansion component enables the ring-shaped main body to be expanded and expanded in one direction, and the outer surface of the main body is pressed and matched with the medullary cavity, so that the prosthesis is pressed and fixed in the femoral medullary cavity, and bone can be obtained in the long term. In addition, a porous structure is formed on the surface of the main body, and the porous structure on the outer surface of the main body can obtain bone ingrowth, so that the reconstructed prosthesis can obtain a long-term biological fixation basis, improve the fixation strength of the long-term femoral-reconstructed prosthesis, and reduce the risk of long-term periprosthetic fracture; bone cement can penetrate into the porous structure on the inner surface of the main body, and the bone cement forms a micro-twisting lock between the inner surface of the main body and the bone cement femoral prosthesis, thereby improving the initial fixation effect of the bone cement femoral stem and the success rate of bone cement femoral prosthesis revision. 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

[0013] Figure 1 It is a structural schematic diagram of the present invention;

[0014] Figure 2 It is another structural schematic diagram of the present invention;

[0015] Figure 3 It is a schematic diagram of the top view of the structure of the present invention;

[0016] Figure 4 It is a cross-sectional structural schematic diagram of the present invention;

[0017] Figure 5 It is a structural schematic diagram of the main body of the present invention. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0019] like Figures 1 to 3 As shown, the present invention provides an expandable prosthesis for cancellous bone reconstruction, comprising a ring-shaped main body 1 and a unidirectional expansion component; a side wall of the main body 1 is formed with a gap 2; the unidirectional expansion component comprises a first expansion piece 3 and a second expansion piece 4 located inside the main body 1 and arranged on both sides of the gap, forming a unidirectional limiting structure between the first expansion piece 3 and the second expansion piece 4 and limiting the relative movement between the two to relative back movement.

[0020] In the above embodiment, preferably, Figure 3 , Figure 4 As shown, the first expansion member 3 and the second expansion member 4 are respectively the first one-way tooth and the second one-way tooth. The first one-way tooth is formed on the main body 1 on one side of the gap, and the tip of each tooth on the first one-way tooth faces the gap. The second one-way tooth is fixed on the main body 1 on the other side of the gap, and the tip of each tooth on the second one-way tooth faces away from the gap. The teeth on the second one-way tooth are engaged with the teeth on the first one-way tooth to form a one-way limiting structure. When an external force is applied to drive the first one-way tooth and the second one-way tooth to move toward each other, the teeth on the first one-way tooth and the teeth on the second one-way tooth are more tightly engaged, that is, the movement of the first one-way tooth and the second guide tooth toward each other is locked. When an external force is applied to drive the first guide tooth and the second one-way tooth to move in reverse, the teeth of the first one-way tooth and the second one-way tooth can slide in reverse relative to each other, so that the gap is stretched and enlarged, that is, the expandability of the outer surface of the main body 1 is realized, and the compression fit between the outer surface of the main body 1 and the inner wall of the femoral medullary cavity is ensured, and bone ingrowth can be obtained in the long term.

[0021] In the above embodiment, preferably, the width of the first one-way tooth and the second one-way tooth is 20% to 100% of the height of the main body 1 .

[0022] In the above embodiment, preferably, Figure 5 As shown, the main body 1 includes a first arc-shaped body 11 and a second arc-shaped body 12 which are hinged to each other, and a gap 2 is formed between the side end surfaces of the first arc-shaped body 11 and the second arc-shaped body 12 to facilitate the expansion of the prosthesis. It should be understood that the structure of the main body 1 is not limited to this, and the main body 1 itself can also expand moderately.

[0023] In the above embodiments, preferably, a porous structure is formed on the surface of the main body 1, and bone cement can penetrate into the porous structure on the inner surface of the main body 1, and the bone cement forms a micro-lock between the inner surface of the main body 1 and the bone cement femoral prosthesis, thereby improving the initial fixation effect of the bone cement handle; the outer surface of the main body 1 is pressed and matched with the inner wall of the femoral medullary cavity to achieve bone ingrowth in the long term; artificial bone or a coating material that promotes bone ingrowth can be sprayed into the porous structure on the outer surface, thereby stimulating bone integration into the porous surface; or, antibiotic drugs or antibacterial materials or coatings are filled in the porous structures on the inner and outer surfaces to prevent periprosthetic infection or promote bone ingrowth.

[0024] In the above embodiment, preferably, Figure 4 As shown, the interior of the main body 1 has a solid layer 100 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.

[0025] 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%.

[0026] In the above embodiment, preferably, the inner surface of the main body 1 is hollow tubular with an inner diameter of 0.8 cm to 6 cm, preferably 1 cm to 2.5 cm. The cross-section of the outer surface of the main body 1 is circular or elliptical or other irregular shapes to adapt to the shape of the intramedullary cavity. When it is circular, the diameter of the outer surface of the main body 1 is 1.2 cm to 6.4 cm. The coronal section of the main body 1 can be rectangular or trapezoidal, with a height of 1 cm to 10 cm, preferably 1.2 cm to 4 cm, and a thickness of 1 mm to 20 mm, preferably 2 mm to 6 mm.

[0027] In the above embodiment, preferably, the main body 1 may be a hollow cylindrical or conical shape, and the taper of the cone is 0° to 30°, preferably 1° to 15°.

[0028] In the above embodiment, preferably, the main body 1 is formed by 3D printing, and the material is a metal material. Specifically, it is formed by electron beam melting or other 3D printing processes, and the material is a titanium alloy or tantalum metal.

[0029] Additionally, based on an expandable prosthesis for cancellous bone reconstruction in any of the above embodiments, the present invention further provides a method for implanting an expandable prosthesis for cancellous bone reconstruction, which comprises the following steps:

[0030] 1) Obtain CT examination data of the patient's hip joint on the affected side and the healthy side before surgery; reconstruct the femoral morphology using a computer, select the expandable prosthesis in any of the above embodiments, or customize the expandable prosthesis in any of the above embodiments according to patient-specific 3D printing;

[0031] 2) Preoperative planning according to preoperative femoral morphology;

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

[0033] 4) Use a special holder to place the expandable ring-shaped prosthesis into the pre-planned position in the medullary cavity, then insert a special expander into the expandable ring-shaped prosthesis, rotate the expander, and gradually expand the expandable ring-shaped prosthesis until the expandable ring-shaped prosthesis is tightly pressed against the inner wall of the medullary cavity;

[0034] 5) Inject bone cement into the medullary cavity to allow the bone cement to penetrate into the expandable prosthesis, and then implant the bone cement femoral stem.

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

Claims

1. An expandable prosthesis for cancellous bone reconstruction, characterized in that: The invention comprises a ring-shaped main body and a one-way expansion component; a gap is formed on the side wall of the main body; the one-way expansion component comprises a first expansion member and a second expansion member located inside the main body and arranged on both sides of the gap, and a one-way limiting structure is formed between the first expansion member and the second expansion member and limits the relative movement of the two to relative back movement; The first expansion member and the second expansion member are respectively a first one-way tooth and a second one-way tooth, the first one-way tooth is formed on the main body at one side of the gap, and each tooth tip on the first one-way tooth points to the gap, the second one-way tooth is fixed on the main body at the other side of the gap, and each tooth tip on the second one-way tooth points away from the gap, and the teeth on the second one-way tooth are engaged with the teeth on the first one-way tooth to form a one-way limiting structure; The main body comprises a first arc-shaped body and a second arc-shaped body hinged to each other, and the gap is formed between the side end surfaces of the first arc-shaped body and the second arc-shaped body; A porous structure is formed on both the inner surface and the outer surface of the main body, and the interior of the main body has a solid layer to prevent bone cement from penetrating from the inner surface into the outer surface.

2. The expandable prosthesis for cancellous bone reconstruction 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%.

3. The expandable prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The inner surface of the main body is hollow tubular with an inner diameter of 0.8 cm to 6 cm, the cross section of the outer surface of the main body is circular or elliptical, the coronal section of the main body is rectangular or trapezoidal, the height of the main body is 1 cm to 10 cm, and the thickness is 1 mm to 20 mm.

4. The expandable prosthesis for cancellous bone reconstruction according to claim 1, characterized in that: The main body is formed by 3D printing and is made of metal material.

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