Movable joint prosthesis

Abstract

The invention provides a movable joint prosthesis which is characterized in that a first prosthesis is used for being connected with a first end of a first bone; the second prosthesis is used for connecting the second end of the second bone; the middle body is positioned between the first prosthesis and the second prosthesis; when the first prosthesis is in a moving state, the friction surface of the first prosthesis can move on the first friction surface of the intermediate in contact with the friction surface and drive the intermediate to move; the second friction surface of the middle body can move on the friction surface of the second prosthesis in contact with the middle body; when the first prosthesis is located at any position in the moving process, the dynamic distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis is not smaller than the initial distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis; the dynamic distance corresponding to one or more positions of the first prosthesis in the movement process is larger than the initial distance. According to the invention, dislocation between the intermediate such as the gasket and the second prosthesis can be reduced.

Description

Technical Field

[0001] This invention relates to an orthopedic joint implant in the field of medical devices, and particularly to a movable joint prosthesis. Background Technology

[0002] Artificial joint prostheses are typically used to replace damaged joint tissues in the human body. For example, a tibial support assembly (hereinafter referred to as a tibial support), a tibial plate assembly (hereinafter referred to as a tibial plate), and a femoral condyle assembly (hereinafter referred to as a tibial condyle) are used to replace a damaged knee joint. Currently, widely used knee prostheses include total knee arthroplasty, unicompartmental knee arthroplasty, and patellofemoral joint prostheses. Taking unicompartmental knee arthroplasty as an example, it is used for articular surface replacement of the medial or lateral compartment of the knee joint. Figure 5 The diagram illustrates the assembled configuration of the prosthesis components after implantation. The tibial support 104 is fixed to the proximal end of the patient's tibia 102 (proximal refers to the point closer to the heart), and the femoral condyle 103 is fixed to the distal end of the patient's femur 101 (distal refers to the point farther from the heart). The tibial spacer 105 is mounted on the tibial support 104, positioned between the tibial support 104 and the femoral condyle 103. Based on the fixation method between the tibial spacer 105 and the tibial support 104, unicompartmental knee prostheses can be classified into mobile and fixed types. In mobile unicompartmental knee prostheses, the tibial spacer 105 can move freely on the platform surface of the tibial support 104, simulating various movements of a normal joint. However, dislocation between the tibial spacer 105 and the tibial support 104 is prone to occur, requiring surgical revision, such as repositioning or replacing the tibial spacer 105; in severe cases, the entire prosthesis may need to be replaced. Summary of the Invention

[0003] The purpose of this invention is to provide a movable joint prosthesis to reduce dislocation of intermediate components such as spacers.

[0004] One technical solution of the present invention is to provide a movable joint prosthesis, comprising:

[0005] The first prosthesis is used to connect to the first end of the first bone.

[0006] The second prosthesis is used to connect to the second end of the second bone.

[0007] An intermediate body is located between the first prosthesis and the second prosthesis;

[0008] The mounting surface of the second prosthesis is used to make close contact with the osteotomy surface of the second end of the second bone; when the first designated point of the mounting surface contacts the first origin of the osteotomy surface, there is a first initial distance between the first designated point and the first origin; when the first designated point is at any offset position that does not contact the first origin, the first dynamic distance between the first designated point and the first origin is not less than the first initial distance; and the first dynamic distance corresponding to one or more of the offset positions is greater than the first initial distance.

[0009] Optionally, when the first prosthesis is in motion, the friction surface of the first prosthesis can move on the first friction surface of the intermediate body in contact with it and drive the intermediate body to move; the second friction surface of the intermediate body can move on the friction surface of the second prosthesis in contact with it.

[0010] When the first prosthesis is in any position during the movement, the second dynamic distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis is not less than the second initial distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis; and the second dynamic distance corresponding to one or more of the movement positions is greater than the second initial distance.

[0011] Optionally, when the first specified point is at the offset position, the first dynamic distance between the first specified point and the first origin is greater than the first initial distance.

[0012] Optionally, the second friction surface of the intermediate body moves on the friction surface of the second prosthesis, including movement or rotation in any direction other than the normal of the friction surface of the second prosthesis.

[0013] Optionally, when the second designated point of the second friction surface of the intermediate body contacts the second origin of the friction surface of the second prosthesis, the distance between the third designated point of the friction surface of the first prosthesis and the second origin is the second initial distance.

[0014] Optionally, the first prosthesis drives the intermediate body to move, so that when the second designated point moves from the second origin to the moving position on the friction surface of the second prosthesis, the second dynamic distance between the third designated point and the second origin is greater than the second initial distance.

[0015] Optionally, the first initial spacing, the first dynamic spacing, the second initial spacing, and the second dynamic spacing refer to the spacing in the Z direction, which is the direction perpendicular to the cross section.

[0016] Optionally, the movable joint prosthesis is a synovial joint.

[0017] Optionally, the first prosthesis is used to connect to the distal end of the first bone;

[0018] The second prosthesis is used to connect to the proximal end of the second bone; the mounting surface of the second prosthesis is a distal mounting surface, which is used to make close contact with the osteotomy surface of the proximal end of the second bone.

[0019] The first designated point is the farthest endpoint of the mounting surface of the second prosthesis; the first origin is the farthest endpoint of the osteotomy surface of the second bone;

[0020] The third designated point is the farthest endpoint of the friction surface of the first prosthesis; the second designated point is the farthest endpoint of the second friction surface of the intermediate body; the second origin is the farthest endpoint of the friction surface of the second prosthesis.

[0021] Optionally, the first prosthesis is used to connect to the proximal end of the first bone;

[0022] The second prosthesis is used to connect to the distal end of the second bone; the mounting surface of the second prosthesis is a proximal mounting surface, which is used to make close contact with the osteotomy surface of the distal end of the second bone.

[0023] The first designated point is the nearest endpoint of the mounting surface of the second prosthesis; the first origin is the nearest endpoint of the osteotomy surface of the second bone.

[0024] The third designated point is the nearest endpoint of the friction surface of the first prosthesis; the second designated point is the nearest endpoint of the second friction surface of the intermediate body; the second origin is the nearest endpoint of the friction surface of the second prosthesis.

[0025] Optionally, the second friction surface of the intermediate body is a first convex surface; the friction surface of the second prosthesis is a first concave surface.

[0026] Optionally, the radius of the first convex surface is not greater than the radius of the first concave surface.

[0027] Optionally, the first convex surface may have a single radius, or the first convex surface may have multiple radii, with at least one of the radii being different from the other radii of the first convex surface.

[0028] Optionally, the first concave surface may have a single radius, or the first concave surface may have multiple radii, with at least one of the radii being different from the other radii of the first concave surface.

[0029] Optionally, the mounting surface of the second prosthesis is a second convex surface, and the osteotomy surface of the second bone is a second concave surface.

[0030] Optionally, the second convex surface may have a single radius, or the second convex surface may have multiple radii, with at least one of the radii being different from the other radii of the second convex surface.

[0031] Optionally, the second concave surface may have a single radius, or the second concave surface may have multiple radii, with at least one of the radii being different from the other radii of the second concave surface.

[0032] Optionally, the friction surface of the first prosthesis is a third convex surface; the first friction surface of the intermediate body is a third concave surface.

[0033] Optionally, the first initial spacing corresponds to the minimum distance between a first designated point on the mounting surface of the second prosthesis and a first origin on the osteotomy surface of the second bone.

[0034] Optionally, the second initial spacing corresponds to the minimum spacing between the friction surfaces of the first prosthesis and the second prosthesis.

[0035] Optionally, the difference between the maximum and minimum distance between the friction surfaces of the first prosthesis and the second prosthesis is 0.05 mm to 10 mm.

[0036] Optionally, the second friction surface of the intermediate body is a first convex surface; the friction surface of the second prosthesis is a first concave surface; the first prosthesis applies a first component force in the positive Z direction to the second prosthesis via the intermediate body, and the second prosthesis provides a fourth component force in the opposite Z direction to the intermediate body, which is opposite to the first component force;

[0037] When the first prosthesis is in motion, a second component force and a third component force in the positive X and Y directions are applied to the second prosthesis via the intermediate body; the second prosthesis provides a fifth component force and a sixth component force in the opposite X and Y directions to the intermediate body to resist the second component force and the third component force; wherein, the fifth component force and the sixth component force increase as the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis increases, so as to constrain the movement range of the intermediate body;

[0038] The Z, X, and Y directions are perpendicular to the cross-section, sagittal plane, and coronal plane, respectively.

[0039] Optionally, the mounting surface of the second prosthesis is a second convex surface, and the osteotomy surface of the second bone is a second concave surface; the second prosthesis applies a seventh component force in the positive Z direction to the second bone, and the second bone provides a tenth component force in the opposite Z direction to the second prosthesis, which is opposite to the seventh component force;

[0040] When the frictional shear force generated by the movement of the intermediate body acts on the second prosthesis, the second prosthesis also provides the second bone with the eighth and ninth component forces in the positive X and Y directions; the second bone provides the second prosthesis with the eleventh and twelfth component forces in the opposite X and Y directions to resist the eighth and ninth component forces; wherein, the eleventh and twelfth component forces increase as the distance in the Z direction between the first designated point of the mounting surface and the first origin of the osteotomy surface increases, so as to prevent the relative movement between the second prosthesis and the second bone and to share the frictional shear force.

[0041] Optionally, the greater the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis, the greater the first return force obtained by the intermediate body; the first return force is used to cause the intermediate body to move in the direction of the second origin.

[0042] The first return force corresponds to the tangential component of the positive Z-direction first component at the first contact point where the second designated point of the second friction surface contacts the friction surface of the second prosthesis; the first return force is minimized when the second designated point contacts the second origin.

[0043] Optionally, the greater the distance in the Z direction between the first designated point of the mounting surface of the second prosthesis and the first origin of the osteotomy surface of the second bone, the greater the second return force obtained by the second prosthesis.

[0044] The second return force corresponds to the tangential component of the seventh component of the positive Z-direction force at the second contact point where the first designated point on the mounting surface contacts the osteotomy surface of the second bone, and is used to counteract at least part of the frictional shear force; the second return force is minimal when the first designated point contacts the first origin.

[0045] Optionally, the movable joint prosthesis is a unicompartmental knee prosthesis applied to the medial condyle.

[0046] Optionally, the movable joint prosthesis is a unicompartmental knee prosthesis applied to the lateral condyle.

[0047] Optionally, when the movable joint prosthesis is a unicompartmental knee prosthesis applied to the medial or lateral condyle, the first prosthesis is a femoral condyle for connecting the distal femur, the second prosthesis is a tibial support for connecting the proximal tibia, and the intermediate body is a tibial pad between the femoral condyle and the tibial support.

[0048] Optionally, when the movable joint prosthesis is an ankle joint prosthesis, the first prosthesis is a talus component for connecting the proximal end of the talus, the second prosthesis is a tibia component for connecting the distal end of the tibia, and the intermediate body is a spacer component between the talus component and the tibia component.

[0049] Another technical solution of the present invention is to provide a movable joint prosthesis, comprising:

[0050] The first prosthesis is used to connect to the first end of the first bone.

[0051] The second prosthesis is used to connect to the second end of the second bone.

[0052] An intermediate body is located between the first prosthesis and the second prosthesis;

[0053] The friction surface of the first prosthesis can move on the first friction surface of the intermediate body it contacts;

[0054] The second friction surface of the intermediate body is a first convex surface; the friction surface of the second prosthesis is a first concave surface; the second friction surface of the intermediate body can move on the friction surface of the second prosthesis in contact with it;

[0055] The mounting surface of the second prosthesis is used to make close contact with the osteotomy surface at the second end of the second bone; the mounting surface is a second convex surface and the osteotomy surface is a second concave surface.

[0056] Optionally, the friction surface of the first prosthesis is a third convex surface; the first friction surface of the intermediate body is a third concave surface.

[0057] Optionally, the radius of the first convex surface is not greater than the radius of the first concave surface.

[0058] Optionally, the radius of the second convex surface is not greater than the radius of the second concave surface.

[0059] Optionally, the first convex surface may have a single radius, or the first convex surface may have multiple radii, with at least one of the radii being different from the other radii of the first convex surface.

[0060] Optionally, the first concave surface may have a single radius, or the first concave surface may have multiple radii, with at least one of the radii being different from the other radii of the first concave surface.

[0061] Optionally, the second convex surface may have a single radius, or the second convex surface may have multiple radii, with at least one of the radii being different from the other radii of the second convex surface.

[0062] Optionally, the second concave surface may have a single radius, or the second concave surface may have multiple radii, with at least one of the radii being different from the other radii of the second concave surface.

[0063] Optionally, the first prosthesis applies a first component force in the positive Z direction to the second prosthesis via an intermediate body, and the second prosthesis provides a fourth component force in the opposite Z direction to the intermediate body, which is opposite to the first component force.

[0064] Optionally, when the first prosthesis is in motion, a second component force and a third component force in the positive X and Y directions are applied to the second prosthesis via the intermediate body; the second prosthesis provides a fifth component force and a sixth component force in the opposite X and Y directions to the intermediate body to resist the second and third component forces; wherein, the fifth and sixth component forces increase as the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis increases, so as to constrain the range of motion of the intermediate body; the Z, X, and Y directions are perpendicular to the cross section, the sagittal plane, and the coronal plane, respectively.

[0065] Optionally, the second prosthesis applies a seventh component force in the positive Z direction to the second bone, and the second bone provides a tenth component force in the opposite Z direction to the second prosthesis, which is opposite to the seventh component force.

[0066] Optionally, when the frictional shear force generated by the movement of the intermediate body acts on the second prosthesis, the second prosthesis also provides the second bone with the eighth and ninth component forces in the positive X and Y directions; the second bone provides the second prosthesis with the eleventh and twelfth component forces in the opposite X and Y directions to resist the eighth and ninth component forces; wherein, the eleventh and twelfth component forces increase as the distance in the Z direction between the first designated point of the mounting surface and the first origin of the osteotomy surface increases, so as to prevent the relative movement between the second prosthesis and the second bone and to share the frictional shear force.

[0067] Optionally, the greater the Z-direction distance between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis, the greater the first return force obtained by the intermediate body; the first return force is used to cause the intermediate body to move in the direction of the second origin.

[0068] Optionally, the first return force corresponds to the tangential component of the positive Z-direction first component at the first contact point where the second designated point of the second friction surface contacts the friction surface of the second prosthesis; the first return force is minimized when the second designated point contacts the second origin.

[0069] Optionally, the greater the Z-direction distance between the first designated point of the mounting surface of the second prosthesis and the first origin of the osteotomy surface of the second bone, the greater the second repositioning force obtained by the second prosthesis.

[0070] Optionally, the second return force corresponds to the tangential component of the seventh component of the positive Z-direction force at the second contact point where the first designated point on the mounting surface contacts the osteotomy surface of the second bone, and is used to counteract at least part of the frictional shear force; the second return force is minimal when the first designated point contacts the first origin.

[0071] Optionally, the movable joint prosthesis is a synovial joint.

[0072] Optionally, the first prosthesis is used to connect the distal end of the first bone; the second prosthesis is used to connect the proximal end of the second bone; the mounting surface of the second prosthesis is a distal mounting surface, which is used to make close contact with the osteotomy surface of the proximal end of the second bone.

[0073] The first designated point is the farthest endpoint of the mounting surface of the second prosthesis; the first origin is the farthest endpoint of the osteotomy surface of the second bone; the second designated point is the farthest endpoint of the second friction surface of the intermediate body; the second origin is the farthest endpoint of the friction surface of the second prosthesis.

[0074] Optionally, the first prosthesis is used to connect the proximal end of the first bone; the second prosthesis is used to connect the distal end of the second bone; the mounting surface of the second prosthesis is a proximal mounting surface, which is used to make close contact with the osteotomy surface of the distal end of the second bone.

[0075] The first designated point is the nearest endpoint of the mounting surface of the second prosthesis; the first origin is the nearest endpoint of the osteotomy surface of the second bone; the second designated point is the nearest endpoint of the second friction surface of the intermediate body; and the second origin is the nearest endpoint of the friction surface of the second prosthesis.

[0076] Optionally, the movable joint prosthesis is a unicompartmental knee prosthesis applied to the medial condyle.

[0077] Optionally, the movable joint prosthesis is a unicompartmental knee prosthesis applied to the lateral condyle.

[0078] Optionally, when the movable joint prosthesis is a unicompartmental knee prosthesis applied to the medial or lateral condyle, the first prosthesis is a femoral condyle for connecting the distal femur, the second prosthesis is a tibial support for connecting the proximal tibia, and the intermediate body is a tibial pad between the femoral condyle and the tibial support; the first designated point is the farthest endpoint of the distal mounting surface of the tibial support; the first origin is the farthest endpoint of the proximal osteotomy surface of the tibia; the second designated point is the farthest endpoint of the distal friction surface of the tibial pad; and the second origin is the farthest endpoint of the proximal friction surface of the tibial support.

[0079] Optionally, when the movable joint prosthesis is an ankle joint prosthesis, the first prosthesis is a talus component for connecting the proximal end of the talus, the second prosthesis is a tibia component for connecting the distal end of the tibia, and the intermediate body is a spacer component between the talus component and the tibia component; the first designated point is the nearest endpoint of the proximal mounting surface of the tibia component; the first origin is the nearest endpoint of the distal osteotomy surface of the tibia; the second designated point is the nearest endpoint of the proximal friction surface of the spacer component; and the second origin is the nearest endpoint of the distal friction surface of the tibia.

[0080] The beneficial effects of this invention are at least as follows:

[0081] In embodiments of the present invention, for a first prosthesis in motion during joint movement and a second prosthesis in a relatively fixed state, the distance between the friction surfaces of the first and second prostheses is controlled so that when the first prosthesis moves through the intermediate body, the dynamic distance between the friction surfaces of the two prostheses is not less than the initial distance between the two friction surfaces (the initial distance is, for example, the minimum distance), and the dynamic distance at one or more points during the movement is greater than the initial distance, thereby preventing the intermediate body from dislodging.

[0082] In embodiments of the present invention, a concave friction surface is provided for the second prosthesis, and the second friction surface of the intermediate body (such as a gasket) in contact with it is set as a convex surface. This design allows the friction surface of the second prosthesis to provide Z-direction support force to the intermediate body, and to apply X and Y-direction lateral forces to constrain the intermediate body. Moreover, the lateral force can increase with the increase of the displacement of the intermediate body relative to the friction surface of the second prosthesis, thus constraining the intermediate body within a certain range of motion and reducing the risk of dislocation between the intermediate body and the second prosthesis.

[0083] In embodiments of the present invention, a raised mounting surface is further provided for the second prosthesis, and the osteotomy surface of the second bone in close contact with it is set as a concave surface. The concave-convex fit between the osteotomy surface and the mounting surface reduces the lateral forces in the X and Y directions transmitted by the second prosthesis to the second bone, thereby reducing the risk of loosening between the second prosthesis and the second bone and improving the stability of osseointegration. Attached Figure Description

[0084] Figure 1 It is a schematic diagram showing the structure and stress analysis of natural joints and various artificial joint prostheses;

[0085] Wherein, a1, b1, c1, and d1 are schematic diagrams of the structure and stress analysis of the first form of the artificial joint prosthesis of the natural joint, the first existing design, and the first and second embodiments of the present invention, respectively; and a2, b2, c2, and d2 are schematic diagrams of the structure and stress analysis of the second form of the artificial joint prosthesis of the natural joint, the existing design, and the first and second embodiments of the present invention, respectively.

[0086] Figure 2 e1, e2, and e3 are schematic diagrams showing the structural conditions when the radius of the second friction surface of the intermediate is equal to, less than, and greater than the radius of the friction surface of the second prosthesis, respectively.

[0087] Figure 3 , Figure 4 These are schematic diagrams showing the friction surface of the second prosthesis in the embodiments of the present invention having a single radius shape and a multi-radius shape.

[0088] Figure 5 This is a schematic diagram of the assembly relationship of a unicompartmental knee joint prosthesis.

[0089] Figure 6 It is a diagram showing the orientation in an anatomical coordinate system.

[0090] Figure 7 'aa' is a schematic diagram of the coordinate system for setting the force on the knee joint; 'bb' is a schematic diagram of the positional relationship between the collateral ligament and the bone at the knee joint.

[0091] Figure 8 This is a diagram showing the inner and outer sides of the knee joint.

[0092] Figure 9 This is an image of a unicompartmental knee joint prosthesis of the second existing design when the spacer dislocates.

[0093] Figure 10 This is a schematic diagram showing the change in distance between the lowest point of the friction surface of the first prosthesis and the origin of the friction surface of the second prosthesis when the first prosthesis and the spacer move toward the edge of the friction surface of the second prosthesis in a unicompartmental knee prosthesis of the first prior art design, Embodiment 1 of the present invention, and the second prior art design. In this diagram, f1 corresponds to the front view and the BB-direction sectional view of the unicompartmental knee prosthesis of the first prior art design; f2 and f3 correspond to the front view and the BB-direction sectional view of the unicompartmental knee prosthesis of Embodiment 1 of the present invention when the spacer is not moved and the prosthesis moves toward the edge; and f4 and f5 correspond to the front view and the BB-direction sectional view of the unicompartmental knee prosthesis of the second prior art design when the spacer is not moved and the prosthesis moves toward the edge.

[0094] Figure 11 yes Figure 10 A schematic diagram showing the change in distance between the lowest point of the first prosthesis friction surface and the origin of the second prosthesis friction surface in a unicompartmental knee joint prosthesis of the first prior art design, Embodiment 1 of the present invention, and the second prior art design.

[0095] Figure 12 This is a three-dimensional diagram illustrating the structure of a unicompartmental knee joint prosthesis under the first existing design.

[0096] Figure 13 yes Figure 12 The diagram shows a top view illustrating the structure of a unicompartmental knee joint prosthesis.

[0097] Figure 14 yes Figure 13 The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the AA direction.

[0098] Figure 15 yes Figure 14 The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the BB direction.

[0099] Figure 16 yes Figure 12 The diagram shows a dislocation of a unicompartmental knee prosthesis under the first existing design.

[0100] Figure 17 This is a three-dimensional schematic diagram of the unicompartmental knee joint prosthesis according to Embodiment 1 of the present invention.

[0101] Figure 18 yes Figure 17 The diagram shows a top view illustrating the structure of a unicompartmental knee joint prosthesis.

[0102] Figure 19 yes Figure 18The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the AA direction.

[0103] Figure 20 yes Figure 19 The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the BB direction.

[0104] Figure 21 This is a top view and cross-sectional views along the AA and BB directions of the pad structure of the unicompartmental knee joint prosthesis described in Embodiment 1 of the present invention.

[0105] Figure 22 This is a top view and cross-sectional views along the AA and BB directions of the tibial support structure of the unicompartmental knee joint prosthesis described in Embodiment 1 of the present invention.

[0106] Figure 23 This is a three-dimensional schematic diagram of the unicompartmental knee joint prosthesis according to Embodiment 2 of the present invention.

[0107] Figure 24 yes Figure 23 The diagram shows a top view illustrating the structure of a unicompartmental knee joint prosthesis.

[0108] Figure 25 yes Figure 24 The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the AA direction.

[0109] Figure 26 yes Figure 25 The diagram shows a schematic cross-sectional view of the unicompartmental knee joint prosthesis along the BB direction.

[0110] Figure 27 This is a top view and cross-sectional views along the AA and BB directions of the tibial support structure of the unicompartmental knee joint prosthesis described in Embodiment 2 of the present invention.

[0111] Figure 28 This is a schematic diagram of the joint motion model of a hinge joint.

[0112] Figure 29 This is a top view of the structure of the first existing ankle joint prosthesis.

[0113] Figure 30 yes Figure 29 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the AA direction.

[0114] Figure 31 yes Figure 29 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the BB direction.

[0115] Figure 32 This is a top view of the structure of the ankle joint prosthesis according to Embodiment 3 of the present invention.

[0116] Figure 33 yes Figure 32 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the AA direction.

[0117] Figure 34 yes Figure 32 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the BB direction.

[0118] Figure 35 This is a top view of the ankle joint prosthesis of Embodiment 4 of the present invention.

[0119] Figure 36 yes Figure 35 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the AA direction.

[0120] Figure 37 yes Figure 35 The diagram shows a schematic cross-sectional view of the ankle joint prosthesis along the BB direction.

[0121] Figure 38 These are front, bottom, and left views of the structure of the pad of the ankle joint prosthesis described in Embodiment 4 of the present invention.

[0122] Figure 39 These are front, bottom, and left views of the tibial component of the ankle joint prosthesis described in Embodiment 4 of the present invention.

[0123] Figure 40 This is a schematic diagram of a "bowl-ball" constraint model formed by the concave and convex surfaces between the second prosthesis and the intermediate body, or by the concave and convex surfaces between the second bone and the second prosthesis, in an artificial joint prosthesis according to an embodiment of the present invention. Here, h1 corresponds to the force analysis diagram when the ball is at the origin of the concave surface of the bowl, and h2 and h3 correspond to the force analysis diagrams when the ball moves to two different positions away from the origin of the concave surface of the bowl. Detailed Implementation

[0124] See Figures 12-15As shown, the first prior art design provides a movable unicompartmental knee prosthesis. When applied to the medial condyle, the cruciate ligament is preserved during clinical surgery, while the tibial articular surface and meniscus are removed and replaced with an artificial tibial support 402 and tibial pad 403. The femoral condyle 401 is fixed to the distal femur via a fixation part 406, and the tibial support 402 is fixed to the proximal tibia via a fixation part 407. The tibial pad 403 is located between the tibial support 402 and the femoral condyle 401. The proximal friction surface 404 of the tibial support 402 and the distal friction surface 405 of the tibial pad 403 are both planar. When these two friction surfaces 404 and 405 come into contact, it is a planar-to-planar contact. Therefore, when the tibial pad 403 moves on the tibial support 402, its movement and rotation in directions other than the height direction are unrestricted. Without the constraints of bones and menisci, the anteroposterior displacement limit of the medial condyle increases, making dislocation between the tibial pad 403 and the tibial support 402 more likely. The tibial support 402 has a sidewall 408 located at one edge of the proximal friction surface 404, which can provide some protection to the tibial pad 403, but cannot completely prevent dislocation such as... Figure 16 The tibial pad 403 shown is dislocated from the edge in other directions.

[0125] See further Figure 1 The simplified model shown illustrates the principle and corresponding measures for spacer dislocation by analyzing the stress conditions of natural joints and artificial joint prostheses. Figure 1 a1 in the figure corresponds to the first form of natural joint. The friction surface 2011 of the first bone 201a is a convex surface that bulges downward, and it can move on the friction surface 2021 of the second bone 202a that is in contact with it. The friction surface 2021 of the second bone 202a is a concave surface that bulges downward, and the radii of the two friction surfaces 2011 and 2021 are matched. Figure 1 a2 in the figure corresponds to the second form of natural joint. The main difference between the first and second forms is that the radii of the friction surfaces 2011' and 2021' of the two bones in contact with each other are different. The radius of the friction surface 2011' of the first bone 201a' is smaller than the radius of the friction surface 2021' of the second bone 202a'. The friction surface 2011' of the first bone 201a' can also move on the friction surface 2021' of the second bone 202a'.

[0126] Figure 1In the first design, b1 and b2 correspond to two forms of artificial joint prostheses. In the first form corresponding to b1, after the diseased joint friction surfaces on the first bone 201b and the second bone 202b are cut off, the joints are reconstructed by replacing them with the first prosthesis 203b and the second prosthesis 204b. The first prosthesis 203b is fixed to the first bone 201b, and the second prosthesis 204b is fixed to the second bone 202b. It is assumed that the second bone 202b and the second prosthesis 204b are fixed during joint movement, while the first bone 201b and the first prosthesis 203b are movable (moving relative to the second bone 202b and the second prosthesis 204b). An intermediate body 205b (e.g., a gasket) is provided between the two prostheses 203b and 204b. The friction surface 2030 of the first prosthesis 203b is a downwardly convex surface (simulating the friction surface 2011 of the first bone 201a of the natural joint in a1), and the first friction surface 2050 of the intervening intermediate body 205b is a downwardly concave surface (simulating the friction surface 2021 of the second bone 202a of the natural joint in a1). The friction surface 2030 of the first prosthesis 203b can contact the first friction surface 2050 of the intermediate body 205b and move on the first friction surface 2050. At the same time, as a movable joint prosthesis, the second friction surface 2051 of the intermediate body 205b can further move or rotate on the friction surface 2041 of the second prosthesis 204b in any direction other than the normal of the friction surface 2041. The contacting friction surfaces 2041 and 2051 are both planar.

[0127] In the first form shown in b1, the friction surface 2030 of the first prosthesis 203b has the same radius as the first friction surface 2050 of the intermediate body 205b; while in the second form shown in b2, the radius of the friction surface 2030' of the first prosthesis 203b' is smaller than the radius of the first friction surface 2050' of the intermediate body 205b'. The structure and motion of other parts are basically the same as in the first form, and will not be described in detail.

[0128] Let's take a mobile unicompartmental knee prosthesis as an example for explanation. Figure 1 In Figure b1, the first bone 201b and the second bone 202b correspond to the femur (distal) and tibia (proximal), respectively; the first prosthesis 203b and the second prosthesis 204b correspond to the femoral condyle and tibial support, respectively; and the intermediate body 205b corresponds to the tibial pad. The friction surface 2041 of the second prosthesis 204b corresponds to the proximal friction surface of the tibial support, and the second friction surface 2051 of the intermediate body 205b corresponds to the distal friction surface of the tibial pad. The contact between these two friction surfaces 2041 and 2051 is a plane-to-plane contact; therefore, the intermediate body 205b has the following characteristics: Figure 16 The dislocation risk is shown.

[0129] See Figure 1 , Figure 6 , Figure 7 As shown in Figure aa, this paper defines the direction perpendicular to the cross-section as the Z direction, the direction perpendicular to the coronal plane as the Y direction, and the direction perpendicular to the sagittal plane as the X direction. ± represents the interaction force, which can be freely defined. (Comparison) Figure 1 From the force conditions in a1 and b1, it can be seen that when the first bone 201a of the natural joint moves or when the first bone 201b of the artificial joint moves the first prosthesis 203b, Fx+( Figure 1 The force components in the three directions Fy+, Fz+, and Fy+ are omitted in the text. For this, the second bone 202a of the natural joint in a1 provides corresponding three negative directions Fx- (…). Figure 1 (omitted in the original text) The force components of Fy- and Fz- are used for balance. However, the movable joint prosthesis under the first existing design shown in b1 lacks sufficient balancing force because the second friction surface 2051 of the intermediate body 205b and the friction surface 2041 of the second prosthesis 204b are two planes in free sliding fit. The end of the intermediate body 205b that contacts the second prosthesis 204b is only constrained by the force in the Fz- direction. The X and Y directions are easy to exceed the friction limit and become unconstrained. Therefore, the intermediate body 205b and the second prosthesis 204b (as shown in the original text) under the first existing design are in a state of equilibrium. Figure 12 The tibial pad 403 and the tibial support 402 are prone to dislocation. Figure 1 The analysis of the stress conditions and dislocation causes of a2 and b2 is similar to the analysis of a1 and b1 above, and will not be repeated here.

[0130] To reduce gasket dislodgement, see Figure 1As shown in c1 and c2, these correspond to two forms of the movable joint prosthesis described in Embodiment 1 of the present invention. In the first form of Embodiment 1 shown in c1, the movable joint prosthesis includes a first prosthesis 203c connected to a first bone 201c, a second prosthesis 204c connected to a second bone 202c, and an intermediate body 205c located between the first prosthesis 203c and the second prosthesis 204c. The friction surface 2033 of the first prosthesis 203c is a downwardly convex surface (simulating the friction surface 2011 of the first bone 201a in the natural joint in a1), and the first friction surface 2053 of the intermediate body 205c that cooperates with it is a downwardly concave surface (simulating the friction surface 2021 of the second bone 202a in the natural joint in a1). The friction surface 2033 of the first prosthesis 203c can contact the first friction surface 2053 of the intermediate body 205c and move on the first friction surface 2053. In this first embodiment, the second friction surface 2052 of the intermediate body 205c is a downwardly convex surface, and the friction surface 2042 of the corresponding and contacting second prosthesis 204c is a downwardly concave surface. The second friction surface 2052 of the intermediate body 205c can move or rotate in any direction other than the normal direction of the friction surface 2042 on the friction surface 2042 of the second prosthesis 204c. The mounting surface 2043 of the second prosthesis 204c and the osteotomy surface 2022 of the second bone 202c connected to the mounting surface 2043 are both planar.

[0131] In the first form of Embodiment 1 shown in c1, the friction surface 2033 of the first prosthesis 203c has the same radius as the first friction surface 2053 of the intermediate body 205c. In the second form of Embodiment 1 shown in c2, the radius of the friction surface 2033' of the first prosthesis 203c' is smaller than the radius of the first friction surface 2053' of the intermediate body 205c'. The structure and motion of other parts are basically the same as in the first form, and will not be described in detail.

[0132] In the first embodiment of the present invention described above, with Figure 1 Taking the force situation of c1 as an example (the force situation of c2 is similar), when the first bone 201c moves the first prosthesis 203c, it will apply force components in three directions: Fx+, Fy+, and Fz+. The concave friction surface 2042 on the second prosthesis 204c provides both support force in the Fz- direction for the intermediate body 205c and lateral constraint force in the Fy- and Fx- directions for the intermediate body 205c, so as to balance the three force components applied by the first bone 201c (the Fx+ or Fx- component is in...). Figure 1(Not shown); Moreover, since the friction surface 2042 of the second prosthesis 204c is concave, the friction surface 2042 is concave in a region closer to the middle and shallower in a region closer to the edge, so that the force in the Fy- and Fx- directions increases with the increase of the displacement of the intermediate body 205c relative to the origin of the friction surface 2042 of the second prosthesis 204c (the origin is the position where the friction surface 2042 is concave the deepest). Thus, when imitating the movement pattern of a natural joint, the intermediate body 205c can be constrained within a certain range of motion, reducing the risk of dislocation between the intermediate body 205c and the second prosthesis 204c.

[0133] Embodiment 2 of the present invention provides another type of movable joint prosthesis. Figure 1 d1 and d2 correspond to the two forms of Embodiment 2, respectively. In the first form of Embodiment 2 shown by d1, the movable joint prosthesis includes a first prosthesis 203d connected to the first bone 201d, a second prosthesis 204d connected to the second bone 202d, and an intermediate body 205d located between the second prosthesis 204d and the first prosthesis 203d. The main difference from Embodiment 1 is that in this Embodiment 2, the mounting surface 2044 of the second prosthesis 204d is a downwardly convex surface, and the osteotomy surface 2023 of the corresponding and connected second bone 202d is a downwardly concave surface, and the concave and convex shapes of the mounting surface 2044 and the osteotomy surface 2023 match each other.

[0134] The structure and motion of other parts in this embodiment are similar to those in embodiment one, such as... Figure 1 As shown in d1, the friction surface 2033 of the first prosthesis 203d is a downwardly convex surface (simulating the friction surface 2011 of the first bone 201a of the natural joint in a1), and the first friction surface 2053 of the mating intermediate body 205d is a downwardly concave surface (simulating the friction surface 2021 of the second bone 202a of the natural joint in a1). The friction surface 2033 of the first prosthesis 203d can contact the first friction surface 2053 of the intermediate body 205d and move on the first friction surface 2053. The second friction surface 2052 of the intermediate body 205d is a downwardly convex surface, and the corresponding and contacting friction surface 2042 of the second prosthesis 204d is a downwardly concave surface. The second friction surface 2052 of the intermediate body 205d can move or rotate on the friction surface 2042 of the second prosthesis 204d in any direction other than the normal of the friction surface 2042.

[0135] In the first form of Embodiment 2 shown in d1, the friction surface 2033 of the first prosthesis 203d has the same radius as the first friction surface 2053 of the intermediate body 205d; while in the second form of Embodiment 2 shown in d2, the radius of the friction surface 2033' of the first prosthesis 203d' is smaller than the radius of the first friction surface 2053' of the intermediate body 205d'. The structure and motion of other parts are basically the same as those in the first form of Embodiment 2, and will not be described in detail.

[0136] In this second embodiment, Figure 1 Taking the force situation of d1 as an example (the force situation of d2 is similar), the concave friction surface 2042 of the second prosthesis 204d provides the intermediate body 205d with a supporting force in the Fz- direction, as well as constraint forces in the Fy- and Fx- directions, to balance the three force components in the Fz+, Fy+, and Fx+ directions applied when the first bone 201d moves the first prosthesis 203d (the component of Fx+ or Fx- is in Figure 1 (Not shown); Since the friction surface 2042 of the second prosthesis 204d is concave (for example, the area closer to the middle is more concave and the area closer to the edge is less concave), the forces in the Fy- and Fx- directions increase as the displacement of the intermediate body 205d relative to the origin of the friction surface 2042 of the second prosthesis 204d increases (the origin is the position where the friction surface 2042 is most concave), thereby constraining the range of motion of the intermediate body 205d and reducing the risk of dislocation between the intermediate body 205d and the second prosthesis 204d.

[0137] The second prosthesis needs to be fixed to the second bone. It is generally undesirable for there to be relative movement (such as lateral sliding) between the mounting surface and the osteotomy surface, otherwise the second prosthesis is prone to loosening. In this embodiment, the mounting surface 2044 of the second prosthesis 204d is convex (for example, the area closer to the center protrudes more, and the area closer to the edge protrudes less), while the osteotomy surface 2023 on the second bone 202d corresponding to the mounting surface 2044 is concave (for example, the concave surface is deeper in the area closer to the center and less in the area closer to the edge, matching the convex surface of the mounting surface 2044). The concave-convex interface between the osteotomy surface 2023 and the mounting surface 2044 in this example constitutes an effective limiting mechanism, making the fixation of the second prosthesis 204d and the second bone 202d more reliable. The principle behind this is explained below.

[0138] When the second friction surface 2052 of the intermediate body 205d moves on the friction surface 2042 of the second prosthesis 204d, the frictional shear force generated by the movement of the intermediate body 205d acts on the second prosthesis 204d. Assuming that the second prosthesis 204d, under the influence of the frictional shear force, moves relative to the second bone 202d in a certain direction (assuming in...), Figure 1When sliding laterally (from center to left), the convex portion of the mounting surface 2044 near this direction (left) is blocked by the concave portion of the osteotomy surface 2923 of the second bone 202d in the same direction (left); moreover, when the forces in the Fx+, Fy+, and Fz+ directions are transmitted to the second bone 202d via the second prosthesis 204d, the second bone 202d provides the second prosthesis 204d with a support force in the Fz- direction and constraint forces in the Fy- and Fx- directions through the concave osteotomy surface 2023 to balance (the component forces of Fx+ or Fx- in... Figure 1 (Not shown) Since the osteotomy surface 2023 is concave, the forces in the Fy- and Fx- directions increase as the distance between the second prosthesis 204d and the deepest concave position on the osteotomy surface 2023 increases. This constrains and restricts the movement of the second prosthesis 204d relative to the second bone 202d and counteracts at least part of the frictional shear force. This improves the ability of the second prosthesis 204d and the second bone 202d to resist lateral sliding, effectively reducing the risk of loosening between the two and improving the stability of the osseointegration between the second prosthesis 204d and the second bone 202d.

[0139] See further Figure 40 The "bowl-sphere" constraint model can be used to illustrate the motion process and force changes when the friction surface (concave bowl surface 2091) of the second prosthesis in Embodiments 1 and 2 of the present invention contacts the second friction surface (convex sphere surface 2081) of the intermediate body, and when the osteotomy surface (concave bowl surface 2091) of the second bone in Embodiment 2 contacts the mounting surface (convex sphere surface 2081) of the second prosthesis. This model is applicable to both forms of Embodiments 1 and 2 (the radius of the convex surface is equal to or less than the radius of the concave surface). The sizes of the sphere and bowl, and the proportional relationships between their radii, are schematic representations used to illustrate the principle and are not intended to be limiting.

[0140] According to this constraint model, the ball 208 is inside the bowl, applying pressure in the Fz+ direction to the bowl; taking the knee joint as an example, the unicompartmental knee prosthesis is installed between the femur (first bone) and the tibia (second bone), and the femur will be affected by gravity and the fibular collateral ligament and tibial collateral ligament (see... Figure 7 The tension of aa and bb) generates Fz+ direction pressure on the unicompartment knee prosthesis, which is further transmitted between the tibial platen and the tibial support (corresponding to the intermediate body and the second prosthesis), and between the tibial support and the tibia (the second prosthesis and the second bone). The deepest point of the concave surface 2091 of the bowl is called the origin 2092 of the surface; according to Figure 40As shown in h1, when the contact point 210 where the convex surface 2081 of the ball and the concave surface 2091 of the bowl coincides with the origin 2092, the pressure in the Fz+ direction passes through the origin 2092 (specifically applied to the concave surface 2091 of the bowl along the normal at the origin 2092), and reaches a state of equilibrium with the support force in the Fz- direction provided by the concave surface 2091 of the bowl to the ball 208.

[0141] according to Figure 40 As shown in h2 and h3, when the ball 208 slides towards the edge of the bowl due to a lateral force (such as inertial force), causing the contact point 210 where the convex surface 2081 of the ball contacts the concave surface 2091 of the bowl to deviate from the origin 2092, the pressure in the Fz+ direction will generate a component force F1 (F1 = Fz+·sinθ, where θ is the slope angle of the concave surface) tangential to the concave surface 2091 and a component force F2 normal to the contact point 210 at the contact point 210; among them, the F1 component force pointing towards the origin 2092 is a return force, which is used to cause the ball 208 to move in the direction of the origin 2092 (relative to the current direction of the ball 208). The upward movement along the concave surface 2091 of the bowl has the opposite trend. During the upward movement shown in h2 to h3, the closer the ball 208 is to the edge of the bowl, the greater the displacement between the contact point 210 and the origin 2092, the larger the angle θ (the slope is steeper when it is close to the edge), and the greater the component force F1 (return force). For example, the return force at h3 is greater than the return force at h2. Until the kinetic energy is completely converted into potential energy, the upward velocity of the ball 208 is zero, and the ball 208 reaches its highest point in the concave surface 2091 of the bowl (assuming it is at h3). After that, the ball 208 slides down the slope under the action of the return force, etc., and returns to the origin 2092.

[0142] Therefore, by forming a geometric shape similar to a "bowl-ball" concave-convex surface to constrain the range of lateral sliding between components, when the second friction surface of the intermediate body corresponds to the convex surface of the ball or the mounting surface of the second prosthesis corresponds to the convex surface of the ball, a return force that can be adaptively adjusted in both direction and magnitude can be obtained by decomposing the Z-direction force (this return force increases as the displacement of the convex surface away from the origin of the concave surface increases, and the direction of the return force always tends towards the origin), causing the ball to return to the origin (return to the equilibrium state). Therefore, from a mechanical point of view, the present invention can achieve a self-stabilizing balance effect between components with a relative sliding tendency through such a "return tendency" that always tends towards the origin, thus eliminating the need to rely on the friction between the contact surfaces or additional mechanical stops. It can also effectively improve the ability of the intermediate body and the second prosthesis described in Embodiments 1 and 2, and the second prosthesis and the second bone in Embodiment 2 to resist lateral sliding, reduce the risk of intermediate body dislocation and prosthesis loosening, and retain the flexibility of the physiological movement of the artificial joint prosthesis.

[0143] In comparison, for such Figure 1In the first existing design shown in b1 and b2, the second friction surface 2051 of the intermediate body 205b and the friction surface 2041 of the second prosthesis 204b, as well as the mounting surface 2043 of the second prosthesis 204b and the osteotomy surface 2022 of the second bone 202b, are all in plane-to-plane contact. The Fz+ pressure transmitted between the components (such as the resultant force of the femoral weight and ligament tension on the unicompartment knee joint prosthesis) is perpendicular to the aforementioned planes. The lateral friction force generated at the contact point can only rely on this Fz+ pressure to resist the lateral forces in the Fy- and Fx- directions transmitted between the components. If the lateral force transmitted from the intermediate body 205b to the second prosthesis 204b exceeds the static friction limit between the second friction surface 2051 and the friction surface 2041, the intermediate body 205b is prone to dislocation; if the lateral force transmitted from the second prosthesis 204b to the second bone 202b exceeds the static friction limit between the mounting surface 2043 and the osteotomy surface 2022, the second prosthesis 204b and the second bone 202b are prone to lateral sliding, posing a risk of mechanical loosening.

[0144] See further Figure 2 As shown, in the movable joint prosthesis of the present invention ( Figure 2 Taking the structure of Embodiment 1 as an example, the situation between the intermediate body and the second prosthesis in Embodiment 2 is similar to that in Embodiment 1 and will not be repeated. The first prosthesis 203e is connected to the first bone 201e, the second prosthesis 204e is connected to the second bone 202e, and an intermediate body 205e is provided between the two prostheses. A friction interface is formed between the intermediate body 205e and the second prosthesis 204e, and the second friction surface 2054 of the intermediate body 205e is a convex surface, while the friction surface 2047 of the second prosthesis 204e in contact with it is a concave surface. Preferably, the radius of the convex surface is not greater than the radius of the concave surface (e1 shows the case where the radius of the second friction surface 2054 of the intermediate body 205e is equal to the radius of the friction surface 2047 of the second prosthesis 204e, and e2 shows the case where the radius of the second friction surface 2054' of the intermediate body 205e' is less than the radius of the friction surface 2047' of the second prosthesis 204e'). This facilitates the formation of an interface lubricating film to reduce interface friction and wear. If, as shown in e3, the radius of the convex surface of the second friction surface 2054” of the intermediate body 205e” is greater than the radius of the concave surface of the friction surface 2047” of the second dummy body 204e”, then the intermediate body 205e” is in an unstable state and the stress condition is very poor; moreover, the gasket used as the intermediate body is generally made of plastic, and in practice, due to plastic creep, it is difficult to achieve the situation where the radius of the convex surface is greater than the radius of the concave surface as shown in e3.

[0145] See also Figure 3 , Figure 4 As shown, in the movable joint prosthesis of the present invention, the arcuate surface of the second prosthesis can have Figure 3The shape shown is 2045 with a single radius, or has Figure 4 The shape 2046 shows multiple radii. The arcuate surface of the second prosthesis can be the friction surface (concave surface) of the second prosthesis in Embodiment 1 or Embodiment 2, or the mounting surface (convex surface) of the second prosthesis in Embodiment 2. For example... Figure 3 The second prosthesis has the same radius R0 at all points on its curved surface. Figure 4 The arcuate surface of the second prosthesis is shown to be composed of three arcuate surfaces with radii R1, R2, and R3, wherein at least one of the arcuate surfaces has a different radius than the other arcuate surfaces, including cases where the radii of each arcuate surface are different (R1, R2, and R3 are only illustrative and are not a limitation on the number of arcuate surfaces or the size relationship between the radii).

[0146] Similarly, the second friction surface (convex surface) of the intermediate described in Embodiment 1 or Embodiment 2 can have an arcuate shape with a single radius or multiple radii (similar). Figure 3 , Figure 4 When the second friction surface has a single radius, the friction surface (concave surface) of the second prosthesis in contact with it can have a single radius or multiple radii, and the single radius of the second friction surface is not greater than the single radius of the friction surface of the second prosthesis or the radius of any segment of its arc surface (according to...). Figure 2 (e1, e2); When the second friction surface has multiple radii, the friction surface (concave surface) of the second prosthesis in contact with it can have a single radius or multiple radii, and the radius of any arc segment of the second friction surface is not greater than the single radius of the friction surface of the second prosthesis or the radius of any arc segment of it (according to...). Figure 2 (e1, e2).

[0147] Similarly, in Embodiment 2, the osteotomy surface (concave surface) of the second bone can have an arcuate shape with a single radius or multiple radii (similar). Figure 3 , Figure 4 Furthermore, it is generally matched with the arc shape and radius setting of the mounting surface (convex surface) of the second prosthesis in Embodiment 2, so as to improve the stability of the osseointegration between the second prosthesis and the second bone.

[0148] In Embodiment 2 of the present invention, the arc surface and radius shape of the friction surface (concave surface) of the second prosthesis, and the arc surface and radius shape of the mounting surface (convex surface) of the second prosthesis, can be set independently. The bending shapes of these two surfaces can be the same or different according to actual application needs (while maintaining the premise that the friction surface of the second prosthesis in contact with the pad is concave and the mounting surface of the second prosthesis in contact with the second bone is convex). As an example, when the friction surface (concave surface) of the second prosthesis has an arc surface shape with a single radius, the mounting surface (convex surface) of the second prosthesis can have an arc surface shape with a single radius or multiple radii. The single radius of the friction surface can be the same as or different from the single radius of the mounting surface of the second prosthesis, or the radius of one or more segments of the multiple arc surfaces of the mounting surface. For example, when the friction surface of the second prosthesis has an arc shape with multiple radii, the mounting surface (convex surface) of the second prosthesis can have an arc shape with a single radius or multiple radii. The radius of one or more segments of the multiple arcs of the friction surface can be the same as or different from the single radius of the mounting surface of the second prosthesis, or the radius of one or more segments of the multiple arcs of the mounting surface.

[0149] In Embodiments 1 and 2 of this invention, the intermediate body is exemplified by a gasket. The gasket can move freely on the friction surface of the second prosthesis. When simulating normal joint movement, the movement trajectory of the gasket does not follow a general pattern, and this invention does not restrict the movement trajectory of the gasket. Therefore, in Embodiments 1 and 2, the range of motion of the gasket is mainly constrained by the concave-convex fit between the friction surface of the second prosthesis and the second friction surface of the gasket. In the preferred example, it is not necessary to set various restrictive structures to guide or limit the movement of the gasket on the friction interface between the gasket and the second prosthesis (the above is an example and not a limitation on the structure of the friction interface between the two; if necessary in actual application, restrictive structures can also be set on the friction interface between the two to guide or limit the movement of the gasket).

[0150] Unlike the embodiments of the present invention where the entire friction surface of the second prosthesis can be concave and the entire friction surface of the pad in contact with it can be convex, in some prior art designs, the friction surface of the second prosthesis only has grooves arranged in the direction that allows the pad to move, and only a portion of the corresponding surface of the pad is set as a flange that can move along the groove. Thus, the direction of the pad's movement is restricted by the cooperation of the downwardly protruding flange of the pad and the downwardly recessed groove of the second prosthesis. Alternatively, in other prior art designs, an upwardly extending portion is formed at the edge of the friction surface of the second prosthesis, and a transverse groove is formed at the extending portion. The thickness of the pad edge matches the transverse groove. Thus, when the pad moves to the edge of the friction surface of the second prosthesis, the pad edge can be embedded in the transverse groove and move along the groove, thereby restricting the boundary of the pad's movement. However, the pad edge is prone to wear after long-term contact with the extended groove. For the embodiments of the present invention, it is not necessary to set similar edge extension portions or transverse grooves on the friction surface of the second prosthesis to restrict the boundary of the pad's movement. Alternatively, in some existing designs, upwardly extending sidewalls are provided on the front and rear sides of the friction surface edge of the second prosthesis to prevent the gasket from dislodging from the front or rear side of the friction surface edge when the second prosthesis moves on the friction surface (e.g., Figure 16 In embodiments of the present invention, it is not necessary to provide similar anterior and posterior sidewalls for the friction surface edge of the second prosthesis. While these prior art designs aim to prevent shim dislocation by guiding or stopping in specific areas or directions, they not only complicate the structure of the friction interface between the shim and the second prosthesis, but also only provide guidance or stopping at the locations or boundaries defined by the contact surface groove, circumferential groove, or sidewall. During movement, the shim is prone to rigid collisions with these structures, significantly affecting the continuity of movement. This restricts the movement of these existing artificial joint prostheses, preventing them from fully simulating the various movement patterns of normal joints. In the preferred embodiment of the present invention, the geometric characteristics and mechanical principles of the concave-convex shape of the component contact surface are used to generate a constraint force against lateral movement through changes in the surface slope. This effectively prevents excessive shim displacement and prosthesis loosening within the concave area of ​​the contact surface. Furthermore, without the aforementioned structural limitations, rigid collisions or edge wear do not occur during shim movement, extending its service life and reducing the probability of prosthesis revision.

[0151] Regarding the movable joint prostheses described in Embodiments 1 and 2 of the present invention, taking the movable unicompartmental knee joint prosthesis as an example, in Figure 1In the first form of embodiment c1, the first bone 201c and the second bone 202c correspond to the femur (distal) and the tibia (proximal), respectively; the first prosthesis 203c and the second prosthesis 204c correspond to the femoral condyle and the tibial support, respectively; and the intermediate body 205c between them corresponds to the tibial pad. The friction surface 2042 of the second prosthesis 204c corresponds to the proximal friction surface (concave surface) of the tibial support, and the second friction surface 2052 of the intermediate body 205c in contact with it corresponds to the distal friction surface (convex surface) of the tibial pad. In the first form of Embodiment 2 in d1, the structure of the friction surface 2042 of the first bone 201d, the first prosthesis 203d, the intermediate body 205d, and the second prosthesis 204d is basically the same as the structure of the same name in c1. The main difference is that in c1, the mounting surface 2043 of the second prosthesis 204c (corresponding to the mounting surface of the distal end of the tibia) and the osteotomy surface 2022 of the second bone 202c (corresponding to the osteotomy surface of the proximal end of the tibia) are both planar, while in d1, the mounting surface 2044 of the second prosthesis 204c is convex and the osteotomy surface 2023 of the second bone 202c is a concave surface that matches the mounting surface 2044. The main difference between the first form shown in c1 and the second form shown in c2 in Example 1 is that the friction surface 2033 of the first prosthesis 203c under c1 has the same radius as the first friction surface 2053 of the intermediate body 205c, while the radius of the friction surface 2033' of the first prosthesis 203c' under c2 is smaller than the radius of the first friction surface 2053' of the intermediate body 205c' (the difference between the first form shown in d1 and the second form shown in d2 in Example 2 is similar to the difference between c1 and c2, and will not be described in detail).

[0152] Figures 17-22 Further, an example structure of a movable unicompartment knee prosthesis corresponding to Embodiment 1 of the present invention is provided, comprising a femoral condyle 411 (corresponding to the first prosthesis), a tibial support 412 (corresponding to the second prosthesis), and a tibial spacer 413 (corresponding to the intermediate body) between the two; the femoral condyle 411 is fixed to the distal femur by a fixation part 416, the tibial support 412 is fixed to the proximal tibia by a fixation part 417, and the tibial spacer 413 is located between the tibial support 412 and the femoral condyle 411. The structure of the fixation parts 416 and 417 shown in this example is only an example and can be adjusted according to actual application needs, for example, by... Figure 17 The plate-shaped fixing part 416 is changed to a structure of one or more fixing posts, and the cross-sectional shape of the fixing posts is set as needed; for example... Figure 17 The fixing part 417 is a plate-shaped keel arranged in the front-back direction. It can be changed into one or more fixing columns, or one or more side wings can be provided for the fixing columns, or the keel and fixing columns can be provided at the same time.

[0153] In this first embodiment, the proximal friction surface 414 of the tibial support 412 is concave (this concave surface is recessed towards the distal end of the tibial support 412, in...) Figure 17 , Figure 19 , Figure 20 The distal friction surface 415 of the tibial pad 413 is convex (this convex surface protrudes further distal to the tibial pad 413, as shown in the image below). Figure 17 , Figure 19 , Figure 20 (Displayed as a downward convex surface). When these two friction surfaces 414 and 415 come into contact, they form a concave-convex fit (the radius of the convex surface is not greater than the radius of the concave surface). The tibial pad 413 can move freely on the friction surface 414 of the tibial support 412. The tibial pad 413 can move or rotate freely in any direction other than the normal direction of the friction surface 414 without restriction. The concave-convex fit of the two friction surfaces 414 and 415 prevents dislocation between the tibial pad 413 and the tibial support 412 (for the force analysis between the tibial pad 413 and the tibial support 412 and the explanation of the anti-dislocation principle, please refer to the above section). Figure 1 (Explanation of c1 and c2 in the text).

[0154] In an optional example, the tibial support 412 has a sidewall 418 located at one edge of the proximal friction surface 414, which can provide some obstruction to the movable tibial pad 413 on this side. For example, if the movable unicompartmental knee prosthesis is for the medial condyle, the sidewall 418 can be located at the lateral edge of the proximal friction surface 414 of the tibial support 412; if it is for the lateral condyle, the sidewall 418 can be located at the medial edge of the proximal friction surface 414 of the tibial support 412. In other examples, the sidewall 418 may be omitted.

[0155] Figures 23-27 This invention also provides an example structure of another movable unicompartment knee joint prosthesis corresponding to Embodiment 2 of the present invention. The structure and arrangement of the femoral condyle 411 (corresponding to the first prosthesis) and its fixation part 416, the tibial support 412' (corresponding to the second prosthesis) and its fixation part 417, and the tibial pad 413 (corresponding to the intermediate body) between the femoral condyle 411 and the tibial support 412' are basically the same as those of the corresponding components in Embodiment 1; moreover, the proximal friction surface 414 of the tibial support 412' is concave (this concave surface is recessed towards the distal end of the tibial support 412', in... Figure 23 , Figure 25 , Figure 26 The distal friction surface 415 of the tibial pad 413 is convex (this convex surface protrudes further distal to the tibial pad 413, as shown in the image below). Figure 23 , Figure 25 , Figure 26(Displayed as a downward convex shape in the image). When these two friction surfaces 414 and 415 come into contact, they form a concave-convex fit (the radius of the convex surface is not greater than the radius of the concave surface). The tibial pad 413 can move or rotate freely on the friction surface 414 of the tibial support 412' in any direction other than the normal direction of the friction surface 414. The concave-convex fit of these two friction surfaces 414 and 415 prevents dislocation between the tibial pad 413 and the tibial support 412' (for the force analysis between the tibial pad 413 and the tibial support 412' and the explanation of the anti-dislocation principle, please refer to the above section). Figure 1 (Explanation of d1 and d2).

[0156] The distal mounting surface of the tibial support 412 as described in Embodiment 1 (see...) Figures 17-20 , Figure 22 Unlike the planar osteotomy surfaces of the tibia and the proximal tibia, in this second embodiment, the distal mounting surface 419 of the tibial support 412' (corresponding to the second prosthesis) is convex (this convex surface protrudes further distal than the tibial support 412'). Figure 23 , Figure 25 , Figure 26 (Displayed as a downward convex shape), after the tibial support 412' is fixedly installed on the proximal tibia, its distal mounting surface 419 will fit tightly against the osteotomy surface of the proximal tibia. The osteotomy surface of the proximal tibia is a concave surface that matches the distal mounting surface 419 of the tibial support 412' (the tibia is in...). Figures 23-27 Not shown in the image; as shown in the image. Figure 1 As shown in d1 and d2, the osteotomy surface of the proximal tibia is concave towards the distal end of the tibia (shown as concave downwards in the illustration). Therefore, with the concave-convex fit between the osteotomy surface of the proximal tibia and the distal mounting surface 419 of the tibial support 412' ( Figure 1 The concave-convex fit between the osteotomy surface 2023 of the second bone and the mounting surface 2044 of the second prosthesis shown in d1 and d2 can effectively improve the anti-lateral sliding ability between the osteotomy surface of the proximal end of the tibia and the distal mounting surface 419 of the tibial support 412', making the connection between the tibial support 412' and the tibia more stable.

[0157] Assuming the second bone and second prosthesis are fixed during joint movement, and the first bone and first prosthesis are movable (moving relative to the first bone and first prosthesis), when the first prosthesis starts from the position where the distance between it and the second prosthesis is minimum (at which position the distance between the friction surfaces of the first and second prostheses is at its minimum), and the first prosthesis moves in any direction other than the normal direction of the friction surface of the second prosthesis while passing through an intermediate body, if the dynamic distance between the friction surfaces of the first and second prostheses can always be maintained at no less than the minimum distance between these two friction surfaces, and if at least one or more points during the movement the dynamic distance is greater than the minimum distance between these two friction surfaces; the distance refers to the distance between the two friction surfaces along the Z-direction (reference...). Figure 1 The straight-line distance between the first prosthesis and the intermediate body is such that, when the above spacing conditions are met, the first prosthesis and the intermediate body are in the cross-section ( Figure 6 Movement in the direction becomes increasingly restricted, thereby reducing the probability of the intermediate body dislodging from the friction surface edge of the second prosthesis. One objective of this invention is to reduce the dislocation rate of the intermediate body by satisfying the aforementioned spacing conditions.

[0158] Taking a unicompartmental knee joint prosthesis as an example, when the above-mentioned spacing conditions are met, starting from the position where the distance between the femoral condyle and the tibial support is at its minimum (at this position, the distance between the distal friction surface of the femoral condyle and the proximal friction surface of the tibial support is also at its minimum), as the femoral condyle moves in any direction other than the normal direction of the proximal friction surface of the tibial support, the dynamic distance between the distal friction surface of the femoral condyle and the proximal friction surface of the tibial support is not less than the minimum distance between the distal friction surface of the femoral condyle and the proximal friction surface of the tibial support, and there is one or more places where the dynamic distance is greater than the minimum distance between these two friction surfaces.

[0159] In Embodiments 1 and 2 of the present invention, the shape design of the contact interface between the first prosthesis and the intermediate body, and between the intermediate body and the second prosthesis, for example, making the friction surface of the first prosthesis convex and the first friction surface of the intermediate body concave; the second friction surface of the intermediate body convex and the friction surface of the second prosthesis in contact with it concave (the radius of the convex surface is not greater than the radius of the concave surface), is one way to satisfy the above-mentioned spacing condition, rather than a limitation on the way the condition is satisfied.

[0160] In some of the following examples, according to Figure 10 The direction shown indicates that the distance between a designated point on the friction surface of the first prosthesis and the origin of the friction surface of the second prosthesis is used as the distance between the two friction surfaces to demonstrate the change from the initial distance to the dynamic distance. In actual applications, depending on the orientation of the artificial prosthesis installation (such as the different cases where the prosthesis connects to the proximal or distal end of the bone in different examples), the lowest point and the highest point mentioned in the text may actually correspond to the nearest endpoint or the farthest endpoint.

[0161] Specifically, see Figure 10 As shown, f1 corresponds to the first existing design of artificial joint prosthesis (and...). Figure 1(corresponding to model b1 in the model), wherein an intermediate body 313 is provided between the first spur 311 and the second spur 312, and the second friction surface 315 of the intermediate body 313 and the friction surface 314 of the second spur 312 in contact with it are both planes; the origin in the first existing design is set as any point on the friction surface 314 (plane) of the second spur 312; when the first spur 311 moves and drives the intermediate body 313 to move on the friction surface 314 of the second spur 312 (when moving in any direction other than the normal direction of the friction surface 314), the distance S0 from the lowest point of the friction surface of the first spur 311 to the origin remains unchanged.

[0162] Figure 10 f2 and f3 correspond to the movable joint prosthesis in Embodiment 1 of the present invention (and) Figure 1 (corresponding to model c1 in the text), wherein an intermediate body 323 is provided between the first prosthesis 321 and the second prosthesis 322, the second friction surface 325 of the intermediate body 323 is a convex surface, and the friction surface 324 of the second prosthesis 322 in contact with it is a concave surface; the origin in embodiment one is set as the lowest point of the friction surface 324 (concave surface) of the second prosthesis 322; at f2, the first prosthesis 321 and the intermediate body 323 have not started to move, and the lowest point of the second friction surface 325 of the intermediate body 323 is at the origin, at which time the friction of the first prosthesis 321 is... The distance from the lowest point of the surface to the origin is the minimum distance between the two, S1 (in this example, S1 = S0); since the friction surface 234 of the second prosthesis 322 is concave, when the first prosthesis 321 moves and drives the intermediate body 323 to move on the friction surface 324 (when moving in any other direction outward from the normal of the friction surface 324), the dynamic distance S1' from the lowest point of the friction surface of the first prosthesis 321 to the origin is not less than the minimum distance between the two, S1, and there is one or more dynamic distances S1' greater than the minimum distance between the two, S1. It can be seen that when the dynamic distance S1' from the lowest point of the friction surface of the first prosthesis 321 to the origin is greater than the minimum value S1, the lowest point of the second friction surface 325 of the intermediate body 323 also deviates from the origin of the friction surface 324 (the lowest point of the concave surface where the friction surface 324 is located). According to the aforementioned bowl-ball constraint model, when the displacement (including the Z-direction distance) between the lowest point of the second friction surface 325 and the origin of the friction surface 324 increases, the Z-direction force and the concave and convex surfaces of the friction surface 324 and the second friction surface 325 work together to enable the intermediate body 323 to obtain a return force that increases with the increase of displacement (including the Z-direction distance), and generate a return tendency to move in the direction of the origin.

[0163] In Embodiment 1 of the present invention, when the lowest point of the second friction surface 325 of the intermediate body 323 moves to the position on the friction surface 324 of the second prosthesis 322 where its movement is allowed to the maximum extent (for example, but not limited to, when the lowest point of the second friction surface 325 is at this position, the lowest point of the second friction surface 325 of the intermediate body 323 or the edge of the second friction surface 325 is on the concave edge of the friction surface 324 of the prosthesis 322 on the same side), the distance from the lowest point of the friction surface of the first prosthesis 321 to the origin is set to the maximum value S1max of the distance between the two. In some examples, the difference between the maximum value S1max of the distance from the lowest point of the friction surface of the first prosthesis 321 to the origin and the minimum value S1 of the distance is between 0.05mm and 10mm.

[0164] Because the unevenness of the second friction surface of the intermediate body and the friction surface of the second prosthesis in contact with it in Embodiment 2 of the present invention is basically the same as that in Embodiment 1 (for example...). Figure 1 The spacing relationship described in Example 1 can also be realized in Example 2 (e.g., the origin of Example 2 is the lowest point of the concave surface corresponding to the friction surface of the second prosthesis, the dynamic distance from the lowest point of the friction surface of the first prosthesis to the origin is not less than the minimum value of the two distances, and there is one or more places where the dynamic distance is greater than the minimum value of the two distances, etc.), which will not be elaborated one by one.

[0165] Figure 10 F4 and F5 also provide a second prior art artificial joint prosthesis, wherein an intermediate body 333 is provided between the first prosthesis 331 and the second prosthesis 332, the second friction surface 335 of the intermediate body 333 is concave, and the friction surface 334 of the second prosthesis 332 in contact with it is convex (the concave-convex relationship of the contact interface between the intermediate body 333 and the second prosthesis 332 is the opposite of the concave-convex relationship of the corresponding components in embodiments one and two of the present invention); the origin of the second prior art is set as the highest point of the friction surface 334 (convex surface) of the second prosthesis 332; in F4, the first prosthesis 331 and the intermediate body 333 have not started. During the movement, the highest point of the second friction surface 335 (concave surface) of the intermediate body 333 is at the origin. At this time, the distance from the lowest point of the friction surface of the first prosthesis 331 to the origin is the maximum value S2 (in this example, S2 = S1 = S0). Since the friction surface 334 of the second prosthesis 332 is convex, the movement of the first prosthesis 331 and the movement of the intermediate body 333 in any direction other than the normal direction on the friction surface 334 will cause the highest point of the second friction surface 335 of the intermediate body 333 to deviate from the origin. In this case, the dynamic distance S2' from the lowest point of the friction surface of the first prosthesis 331 to the origin will be less than the maximum value S2 of the distance between the two.

[0166] according to Figure 11 As shown, g0, g1, and g2 respectively correspond to Figure 10In the first existing design, Embodiment 1 (and Embodiment 2) of the present invention, and the second existing design, the dynamic distance between the lowest point of the first prosthesis friction surface and the origin changes as the distance between the lowest point and the origin increases. Here, g0 is a horizontal straight line, indicating that in the first existing design, even if the first prosthesis 311 and the intermediate body 313 move on the friction surface 315 (plane) of the second prosthesis 312, the distance between the lowest point of the friction surface of the first prosthesis 311 and the origin remains unchanged. g2 is an upward-curving curve, indicating that in the embodiments of the present invention, as the first prosthesis 321 and the intermediate body 323 move on the friction surface 325 (concave) of the second prosthesis 322, and the distance between the lowest point of the second friction surface 324 of the intermediate body 323 and the origin increases, the distance between the lowest point of the friction surface of the first prosthesis 321 and the origin gradually increases. g3 is a downward-curving curve. It can be seen that in the second prior art design, as the first prosthesis 331 and the intermediate body 333 move on the friction surface 335 (convex surface) of the second prosthesis 332, the distance between the lowest point of the second friction surface 334 of the intermediate body 333 and the origin increases, and the distance between the lowest point of the friction surface of the first prosthesis 331 and the origin gradually decreases. Therefore, neither the first nor the second prior art design of the artificial joint prosthesis meets the spacing conditions required by the present invention (i.e., the dynamic spacing between the friction surfaces of the first and second prostheses in the first or second prior art design cannot meet the requirement that it is not less than the minimum distance between these two friction surfaces, and that at least one or more points during movement have a dynamic spacing greater than the minimum distance between these two friction surfaces), thus weakening the effect of preventing intermediate body dislocation.

[0167] See also Figure 10 As shown in f1 to f5, the top surface of the first prosthesis and the bottom surface of the second prosthesis are set as reference points on these two prostheses (this is just an example of reference points; in other examples, reference points on the prostheses can be freely defined). Thus, the change in the distance between the two prostheses can be more clearly reflected by the change in the distance between the two reference points. The changing trend of the distance between the two reference points is the same as the changing trend of the distance between the friction surfaces of the two prostheses. That is, if the distance between the friction surfaces increases, the distance between the reference points increases, and the distance between the prostheses increases; conversely, if the distance between the friction surfaces decreases, the distance between the reference points decreases, and the distance between the prostheses decreases.

[0168] Figure 10 In the first existing design shown in f1, when the first prosthesis 311 moves and drives the intermediate body 313 to move on the friction surface 314 (plane) of the second prosthesis 312, the distance L0 between the reference point of the first prosthesis 311 and the reference point of the second prosthesis 312 remains unchanged.

[0169] f2 and f3 correspond to Embodiment 1 of the present invention. When the lowest point of the second friction surface 325 (convex surface) of the intermediate body 323 is at the origin (as in f2), the distance between the reference point of the first prosthesis 321 and the reference point of the second prosthesis 322 is called the initial reference point distance L1. The first prosthesis 321 drives the intermediate body 323 to move on the friction surface 324 (concave surface) of the second prosthesis 322. The distance between the reference point of the first prosthesis 321 and the reference point of the second prosthesis 322 is called the dynamic reference point distance L1'. The dynamic reference point distance L1' is not less than the initial reference point distance L1, and when the first prosthesis 321 drives the intermediate body 323 to move, the dynamic reference point distance L1' at least one point will be greater than the initial reference point distance L1 (similar to the case of the dynamic distance S1' and the initial distance S1 mentioned above).

[0170] f4 and f5 correspond to the second existing design. When the highest point of the second friction surface 335 of the intermediate body 333 is at the origin (as in f4), the distance between the reference point of the first spur 331 and the reference point of the second spur 332 is called the initial reference point distance L2. The first spur 331 drives the intermediate body 333 to move on the friction surface 334 (convex surface) of the second spur 332. The distance between the reference point of the first spur 331 and the reference point of the second spur 332 is called the dynamic reference point distance L2'. The dynamic reference point distance L2' is not greater than the initial reference point distance L2, and when the first spur 331 drives the intermediate body 333 to move, the dynamic reference point distance L2' at least one point will be less than the initial reference point distance L2.

[0171] Comparing Embodiment 1 of the present invention and the second prior art design, it can be seen that the initial reference point spacing L1 in the example of the present invention can be the minimum spacing between two reference points. However, as long as the lowest point of the second friction surface 325 (convex surface) of the intermediate body 323 deviates from the origin during movement (e.g., f3), the dynamic reference point spacing L1' will be greater than the initial reference point spacing L1. Furthermore, since the friction surface 324 of the second prosthesis 322 is concave, the dynamic reference point spacing L1' will continuously increase as the distance of the lowest point of the second friction surface 325 of the intermediate body 323 from the origin increases. In contrast, the initial reference point spacing L2 in the second prior art design is the maximum spacing between two reference points. However, as long as the highest point of the second friction surface 335 (concave surface) of the intermediate body 333 deviates from the origin during movement (e.g., f5), the dynamic reference point spacing L2' will be less than the initial reference point spacing L2. Furthermore, since the friction surface 334 of the second prosthesis 332 is concave, the dynamic reference point spacing L2' will continuously decrease as the distance of the highest point of the second friction surface 335 of the intermediate body 333 from the origin increases.

[0172] See also Figure 9 and Figure 10As shown in f4 and f5, the second existing design provides a unicompartmental knee prosthesis specifically for the lateral condyle, such that the first prosthesis 331 is fixed to the femoral condyle on the lateral articular surface of the distal femur; the second prosthesis 332 is fixed to the tibial support on the lateral proximal tibia, and the friction surface 334 of the second prosthesis 332 is the proximal friction surface of the tibial support, which is a convex surface; the mounting surface of the second prosthesis 332 is the distal mounting surface of the tibial support, which is a flat surface; the intermediate body 333 corresponds to the tibial pad between the two prostheses, and the first friction surface and the second friction surface 335 of the intermediate body 333 correspond to the proximal and distal friction surfaces of the tibial pad, both of which are concave surfaces.

[0173] The medial side of the human knee joint refers to the side closer to the body's center line, while the lateral side refers to the side farther from the body's center line. Figure 8 The range of motion of the lateral femoral condyle is significantly greater than that of the medial femoral condyle (e.g., the anteroposterior range of motion of the medial femoral condyle is 3mm, while that of the lateral femoral condyle is 18mm). The main reason for this movement pattern is the combined action of muscles, bones, lateral ligaments, cruciate ligaments, and menisci. Simplifying and eliminating the influence of soft tissue tension, the degree of concavity of the medial meniscus is similar to that of the convexity of the medial condyle (i.e., high conformation), while the conformation of the lateral meniscus to the lateral condyle is low. The articular surfaces of the tibia also exhibit a shape characteristic of being concave on the medial side and convex on the lateral side. Therefore, during flexion, the medial condyle is generally confined to a small area approximately in the center, with little change in its anteroposterior position.

[0174] according to Figure 10 As can be seen from f4 and f5, when the second existing design is used as a unicompartmental knee joint prosthesis for the lateral condyle, the highest point of the second friction surface 335 of the intermediate body 333 is at the origin, corresponding to the highest point of the distal friction surface of the tibial pad at the proximal friction surface of the tibial support. When the highest point of the second friction surface 335 of the intermediate body 333 moves in any direction (outward), the dynamic distance S2' from the lowest point of the friction surface of the first prosthesis 331 to the origin of the friction surface 334 continuously decreases. During this process, the collateral ligaments at the knee joint will become looser and looser, and a relatively free and larger range of motion can be obtained. This is similar to the lateral movement characteristics of natural joints. Therefore, f4 and f5 can be applied to the lateral unicompartmental knee joint. However, ligament laxity can easily cause the mating surfaces of the intermediate body 333 and the second prosthesis 332 to detach from each other. The concave-convex fit between the second friction surface 335 of the intermediate body 333 and the friction surface 334 of the second prosthesis 332 (opposite to the embodiment of the present invention) is similar to the shape of a "bowl on bowl". It cannot provide the pad with a return force that increases with the offset distance and tends to the origin. Therefore, the second existing design of the pad does not have an adaptive adjustment return tendency and cannot achieve the effect of self-stabilizing balance. The effect of preventing the pad dislocation is weak. In actual clinical application, it is not successful. The dislocation rate of the pad is as high as 1% to 6%.

[0175] In comparison, according to Figure 10 As shown in f2 and f3, in Embodiment 1 of the present invention as a unicompartmental knee joint prosthesis, the lowest point of the second friction surface 325 of the intermediate body 323 is at the origin, corresponding to the farthest point of the distal friction surface of the tibial pad being at the farthest point of the proximal friction surface of the tibial support. When the second friction surface 325 of the intermediate body 323 moves from the lowest point in any direction (outward from the normal direction), the dynamic distance S1' from the lowest point of the friction surface of the first prosthesis 321 to the origin of the friction surface 324 continuously increases. This can make the ligaments tighter and tighter, resulting in stronger ligament tension (increased Z-force). The return force on the pad towards the origin is greater, thereby constraining the range of motion of the pad and effectively reducing the dislocation rate of the pad. At the same time, the range of motion of the pad is relatively narrow and small, which will... The medial aspect of the natural joint has more similar movement characteristics. Therefore, in the preferred example, the unicompartmental knee prosthesis of Embodiment 1 of the present invention can be applied to the medial unicompartment. Since the dynamic distance L1' between the reference points of the two prostheses in Embodiment 1 is not less than the initial distance L1 between the reference points, it is also not less than the distance L0 between the reference points of the two prostheses when sliding in a plane as shown in the first existing design (f1), that is, L1'≥L1=L0 (corresponding to the distance control of the friction surfaces of the two prostheses as shown in S1'≥S1=S0). Therefore, Embodiment 1 of the present invention effectively restrains the femoral condyle (first prosthesis 321), which will not move freely without restriction as in the first existing design, greatly reducing the risk of the tibial pad (intermediate body 323) dislocating from the edge.

[0176] In the first embodiment of the present invention, when the unicompartmental knee prosthesis is applied to a medial unicompartmental knee, the first prosthesis 321 corresponds to the femoral condyle fixed to the medial articular surface of the distal femur; the second prosthesis 322 corresponds to the tibial support fixed to the medial aspect of the proximal tibia, and the friction surface 324 of the second prosthesis 322 is the proximal friction surface of the tibial support, which is a concave surface; the intermediate body 323 corresponds to the tibial pad between the femoral condyle and the tibial support, and the first friction surface of the intermediate body 323 corresponds to the proximal friction surface of the tibial pad, which is a concave surface, and the distal friction surface of the femoral condyle contacts the concave surface; the second friction surface 325 of the intermediate body 323 corresponds to the distal friction surface of the tibial pad, which is a convex surface, and contacts the concave surface of the proximal friction surface of the tibial support; the mounting surface of the second prosthesis 322 should correspond to... In this embodiment, the distal mounting surface of the tibial support is a plane, and the osteotomy surface on the medial side of the proximal tibia to be fixed is the corresponding plane. (In embodiment two, the structure and principle of preventing the pad dislocation are the same as in embodiment one, but the distal mounting surface of the tibial support is further modified to be convex, and the corresponding osteotomy surface on the medial side of the proximal tibia is concave. In this way, when the ligament tension increases, the Z-direction force transmitted to the mating surface between the tibial support and the tibia increases. Combined with the concave and convex shape of the proximal osteotomy surface of the tibia and the distal mounting surface of the tibial support, the tibial support obtains a return force that increases with the displacement (including the Z-direction distance) of the osteotomy surface origin and always tends towards the origin, thereby effectively preventing the tibial support from sliding laterally relative to the tibia and reducing the risk of prosthesis loosening. See...) Figure 1 d1, d2 and Figure 40 However, the above are merely examples and are not intended to limit the application scenarios of Embodiments 1 and 2 of the present invention. In other examples, unicompartmental knee joint prostheses can still be used for the lateral condyle. Based on a similar principle of Z-axis force and concave-convex surface morphology, the effect of reducing spacer dislocation and preventing prosthesis loosening can be achieved.

[0177] The movable joint prosthesis provided in this invention is not limited to the unicompartmental knee joint prosthesis described above, but can also be applied to other synovial joints such as the elbow, ankle, and interphalangeal joints. The following description uses an ankle joint prosthesis as an example; an ankle joint prosthesis is a hinge joint. Figure 28 A joint motion model of a hinge joint is shown.

[0178] like Figures 29-31The diagram shows a movable ankle joint prosthesis provided by a first prior art design, comprising a talus component 501 (first prosthesis), a tibia component 502 (second prosthesis), and a spacer component 503 (intermediate body); wherein, the talus component 501 is connected to the proximal end of the talus; the tibia component 502 is connected to the distal end of the tibia via a fixing part 506, and the proximal mounting surface 507 of the tibia component 502 is in close contact with the osteotomy surface of the distal end of the tibia, the proximal mounting surface 507 and the osteotomy surface are two matching planes. The proximal contact surface of the talus component 501 is an upwardly convex surface, which contacts and can move on the distal friction surface (first friction surface of the intermediate body) of the pad component 503. The distal friction surface of the pad component 503 is an upwardly concave surface. The proximal friction surface 505 (second friction surface of the intermediate body) of the pad component 503 is a plane, which contacts the plane containing the distal friction surface 504 (friction surface of the second prosthesis) of the tibia component 502, and can move on the distal friction surface 504. According to the preceding text... Figure 1 China Figure 1 As can be seen from the descriptions of b1 and b2, under the first existing design, the proximal friction surface 505 of the gasket component 503 and the distal friction surface 504 of the tibia component 502 are in a planar sliding fit. The gasket component 503 is not constrained in the X and Y directions and is easy to dislodge from the edge of the distal friction surface 504.

[0179] like Figures 32-34 The image shows a movable ankle joint prosthesis according to Embodiment 3 of the present invention, comprising a talus component 511 (first prosthesis), a tibia component 512 (second prosthesis), and a spacer component 513 between the two; wherein, the talus component 511 is connected to the proximal end of the talus; the proximal contact surface of the talus component 511 is convex (protruding in a direction further proximal than the talus component 511), Figure 33 (Displayed as an upward convex surface), which contacts the distal friction surface (first friction surface of the gasket) of the gasket component 513 and can move on that surface. The distal friction surface of the gasket component 513 is concave (recessed towards the proximal end of the gasket component 513). Figure 33 (As shown in the image, it is concave upwards). The tibial component 512 is connected to the distal end of the tibia via a fixing part 516, and the proximal mounting surface 517 of the tibial component 512 is in close contact with the osteotomy surface of the distal tibia; in this embodiment, the proximal mounting surface 517 and the osteotomy surface are two matching planes. The fixing part 516 in the example includes two rows of keels, and the structure, number, or position of the fixing part 516 can be adjusted according to the actual application needs.

[0180] The main difference from the first existing design is that the proximal friction surface 515 (the second friction surface of the intermediate body) of the gasket component 513 in Embodiment 3 of the present invention is a convex surface (protruding towards a direction closer to the gasket component 513). Figure 33(As shown in the image, it is convex upwards), and the distal friction surface 514 of the tibial component 512 (the friction surface of the second prosthesis) that contacts it is concave (concave towards the proximal end of the tibial component 512). Figure 33 (Displayed as an upward concave shape); the radius of the convex surface of the proximal friction surface 515 of the pad component 513 is not greater than the radius of the concave surface of the distal friction surface 514 of the tibia component 512. When the talus component 511 moves, it causes the proximal friction surface 515 of the pad component 513 to move freely on the distal friction surface 514 of the tibia component 512, allowing for movement or rotation in any direction other than the normal direction of the distal friction surface 514.

[0181] When the talus component 511 and the pad component 513 move, the dynamic distance (Z-direction linear distance) between the proximal friction surface of the talus component 511 and the distal friction surface 514 of the tibia component 512 is not less than the minimum distance between these two friction surfaces, and there is one or more points where the dynamic distance is greater than this minimum value. In this example, the highest point (nearest endpoint) of the distal friction surface 514 of the tibia component 512 is set as the origin. When the highest point (nearest endpoint) of the proximal friction surface 515 of the pad component 513 moves from the origin to any other direction, the dynamic distance between the highest point (nearest endpoint) of the proximal friction surface of the talus component 511 and the origin increases, and the distance between the talus component 511 and the tibia component 512 also increases accordingly (similar to...). Figure 10 In cases f2 and f3, but with the prosthesis positioned opposite in the human body (the highest point of the proximal friction surface 515 of the gasket component 513 is at the origin), the aforementioned spacings are at their respective minimum values. Based on the aforementioned... Figure 1 c1, c2 and Figure 10 The first embodiment shown in f2 and f3 is as follows: Figure 40 Analysis of the anti-dislocation effect of the bowl-ball constraint model shown shows that this third embodiment can effectively reduce the possibility of the gasket component 513 dislodging from the edge.

[0182] like Figures 35-39 The image shows another movable ankle joint prosthesis provided in Embodiment 4 of the present invention, which also includes a talus component 511 (first prosthesis), a tibia component 512' (second prosthesis), and a spacer component 513 between them; the main difference from Embodiment 3 is that the proximal mounting surface 517' of the tibia component 512' in Embodiment 4 is a convex surface (protruding towards a direction more proximal than the tibia component 512', in Figure 36 The central part is shown as an upward convex surface, and the distal osteotomy surface of the tibia in close contact with it is concave (indented towards the proximal end of the tibia). Based on the aforementioned... Figure 1 Example 2 shown in d1 and d2 Figure 40Analysis of the bowl-ball constraint model, etc., shows that when the talus component 511 moves the pad component 513, it applies force components in the X, Y, and Z directions. Among them, the lateral force in the X and Y directions is transmitted to the distal tibia via the tibial component 512'. Through the concave-convex fit between the osteotomy surface of the distal tibia and the proximal mounting surface 517' of the tibial component 512', the opposite force component is adaptively generated to counteract the lateral force transmitted by the tibial component 512'. This improves the anti-lateral sliding performance between the tibial component 512' and the distal tibia, reduces the risk of loosening between them, and makes the installation and fixation of the tibial component 512' and the distal tibia more stable.

[0183] In this fourth embodiment, the structure, contact interface morphology, movement, stress, and spacing changes of other parts are similar to those in the third embodiment. For example, the proximal contact surface (convex surface) of the talus component 511 can move on the distal friction surface (concave surface) of the pad component 513 that it contacts. The proximal friction surface 515 of the pad component 513 is a convex surface, and the distal friction surface 514 of the tibia component 512' that it contacts is a concave surface, and the radius of the convex surface is not greater than the radius of the concave surface. When the talus component 511 moves the pad component 513, the dynamic spacing between the proximal friction surface of the talus component 511 and the distal friction surface 514 of the tibia component 512' is not less than the minimum spacing between these two friction surfaces, and there is one or more places where the dynamic spacing is greater than the minimum value. When the highest point (nearest endpoint) of the proximal friction surface 515 of the pad component 513 moves from the origin (the highest point of the distal friction surface 514 of the tibial component 512', i.e., the nearest endpoint) in any other direction outward from the normal, the dynamic distance between the proximal friction surface (highest point, i.e., the nearest endpoint) of the talus component 511 and the origin increases, and the distance between the talus component 511 and the tibial component 512' also increases accordingly, so as to reduce the possibility of the pad component 513 dislocating from the edge and effectively reduce the dislocation rate.

[0184] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A movable joint prosthesis, characterized in that, Include: The first prosthesis is used to connect to the first end of the first bone. The second prosthesis is used to connect to the second end of the second bone. An intermediate body is located between the first prosthesis and the second prosthesis; The mounting surface of the second prosthesis is used to make close contact with the osteotomy surface of the second end of the second bone; when the first designated point of the mounting surface contacts the first origin of the osteotomy surface, there is a first initial distance between the first designated point and the first origin; when the first designated point is at any offset position that does not contact the first origin, the first dynamic distance between the first designated point and the first origin is not less than the first initial distance. Furthermore, the first dynamic spacing corresponding to one or more of the offset positions is greater than the first initial spacing; When the first prosthesis is in motion, the friction surface of the first prosthesis can move on the first friction surface of the intermediate body in contact with it and drive the intermediate body to move; the second friction surface of the intermediate body can move on the friction surface of the second prosthesis in contact with it. When the first prosthesis is in any position during the movement, the second dynamic distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis is not less than the second initial distance between the friction surface of the first prosthesis and the friction surface of the second prosthesis. Furthermore, the second dynamic spacing corresponding to one or more of the movement positions is greater than the second initial spacing.

2. The movable joint prosthesis as described in claim 1, characterized in that, When the first designated point is at the offset position, the first dynamic distance between the first designated point and the first origin is greater than the first initial distance; The second friction surface of the intermediate body moves on the friction surface of the second prosthesis, including movement or rotation in any direction other than the normal of the friction surface of the second prosthesis; When the second designated point of the second friction surface of the intermediate body contacts the second origin of the friction surface of the second prosthesis, the distance between the third designated point of the friction surface of the first prosthesis and the second origin is the second initial distance. When the first prosthesis drives the intermediate body to move, and when the second designated point moves from the second origin to the moving position on the friction surface of the second prosthesis, the second dynamic distance between the third designated point and the second origin is greater than the second initial distance. The first initial spacing, the first dynamic spacing, the second initial spacing, and the second dynamic spacing refer to the spacing in the Z direction, which is perpendicular to the cross-section.

3. The movable joint prosthesis as described in claim 2, characterized in that, The movable joint prosthesis is a synovial joint; The first prosthesis is used to connect to the distal end of the first bone; The second prosthesis is used to connect to the proximal end of the second bone; the mounting surface of the second prosthesis is a distal mounting surface, which is used to make close contact with the osteotomy surface of the proximal end of the second bone. The first designated point is the farthest endpoint of the mounting surface of the second prosthesis; The first origin is the farthest point of the osteotomy surface of the second bone; The third designated point is the farthest endpoint of the friction surface of the first prosthesis; The second designated point is the farthest endpoint of the second friction surface of the intermediate body; The second origin is the farthest point of the friction surface of the second prosthesis.

4. The movable joint prosthesis as described in claim 2, characterized in that, The movable joint prosthesis is a synovial joint; The first prosthesis is used to connect to the proximal end of the first bone; The second prosthesis is used to connect to the distal end of the second bone; the mounting surface of the second prosthesis is a proximal mounting surface, which is used to make close contact with the osteotomy surface of the distal end of the second bone. The first designated point is the nearest endpoint of the mounting surface of the second prosthesis; The first origin is the nearest endpoint of the osteotomy surface of the second bone; The third designated point is the nearest endpoint of the friction surface of the first prosthesis; The second designated point is the nearest endpoint of the second friction surface of the intermediate body; The second origin is the nearest endpoint of the friction surface of the second prosthesis.

5. The movable joint prosthesis as described in claim 3 or 4, characterized in that, The second friction surface of the intermediate is a first convex surface; The friction surface of the second prosthesis is the first concave surface; The radius of the first convex surface is not greater than the radius of the first concave surface; The first convex surface has a single radius, or the first convex surface has multiple radii, and at least one of the radii is different from the other radii of the first convex surface; The first concave surface has a single radius, or the first concave surface has multiple radii, and at least one of the radii is different from the other radii of the first concave surface.

6. The movable joint prosthesis as described in claim 3 or 4, characterized in that, The mounting surface of the second prosthesis is a second convex surface, and the osteotomy surface of the second bone is a second concave surface; the second convex surface has a single radius, or the second convex surface has multiple radii, and at least one of the radii is different from the other radii of the second convex surface; The second concave surface has a single radius, or the second concave surface has multiple radii, and at least one of the radii is different from the other radii of the second concave surface.

7. The movable joint prosthesis as described in claim 3 or 4, characterized in that, The friction surface of the first prosthesis is a third convex surface; The first friction surface of the intermediate is the third concave surface.

8. The movable joint prosthesis as described in claim 1 or 2, characterized in that, The first initial spacing corresponds to the minimum spacing between the first designated point on the mounting surface of the second prosthesis and the first origin on the osteotomy surface of the second bone; The second initial spacing corresponds to the minimum spacing between the friction surfaces of the first prosthesis and the second prosthesis.

9. The movable joint prosthesis as described in claim 1 or 2, characterized in that, The difference between the maximum and minimum distance between the friction surfaces of the first prosthesis and the second prosthesis is 0.05 mm to 10 mm.

10. The movable joint prosthesis as described in claim 3 or 4, characterized in that, The second friction surface of the intermediate body is a first convex surface; the friction surface of the second prosthesis is a first concave surface; the first prosthesis applies a first component force in the positive Z direction to the second prosthesis via the intermediate body, and the second prosthesis provides a fourth component force in the opposite Z direction to the intermediate body, which is opposite to the first component force; When the first prosthesis is in motion, a second component force and a third component force in the positive X and Y directions are applied to the second prosthesis via the intermediate body; the second prosthesis provides a fifth component force and a sixth component force in the opposite X and Y directions to the intermediate body to resist the second component force and the third component force; wherein, the fifth component force and the sixth component force increase as the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis increases, so as to constrain the movement range of the intermediate body; The Z, X, and Y directions are perpendicular to the cross-section, sagittal plane, and coronal plane, respectively.

11. The movable joint prosthesis as described in claim 10, characterized in that, The mounting surface of the second prosthesis is a second convex surface, and the osteotomy surface of the second bone is a second concave surface; the second prosthesis applies a seventh component force in the positive Z direction to the second bone, and the second bone provides a tenth component force in the opposite Z direction to the second prosthesis, which is opposite to the seventh component force; When the frictional shear force generated by the movement of the intermediate body acts on the second prosthesis, the second prosthesis also provides the second bone with the eighth and ninth component forces in the positive X and Y directions; the second bone provides the second prosthesis with the eleventh and twelfth component forces in the opposite X and Y directions to resist the eighth and ninth component forces; wherein, the eleventh and twelfth component forces increase as the distance in the Z direction between the first designated point of the mounting surface and the first origin of the osteotomy surface increases, so as to prevent the relative movement between the second prosthesis and the second bone and to share the frictional shear force.

12. The movable joint prosthesis as described in claim 10, characterized in that, The greater the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis, the greater the first return force obtained by the intermediate body; the first return force is used to cause the intermediate body to move in the direction of the second origin. The first return force corresponds to the tangential component of the positive Z-direction first component at the first contact point where the second designated point of the second friction surface contacts the friction surface of the second prosthesis; the first return force is minimized when the second designated point contacts the second origin.

13. The movable joint prosthesis as described in claim 11, characterized in that, The greater the Z-direction distance between the first designated point of the mounting surface of the second prosthesis and the first origin of the osteotomy surface of the second bone, the greater the second return force obtained by the second prosthesis. The second return force corresponds to the tangential component of the seventh component of the positive Z-direction force at the second contact point where the first designated point on the mounting surface contacts the osteotomy surface of the second bone, and is used to counteract at least part of the frictional shear force; the second return force is minimal when the first designated point contacts the first origin.

14. The movable joint prosthesis according to any one of claims 1 to 4, characterized in that, When the movable joint prosthesis is applied to a unicompartmental knee joint prosthesis of the medial or lateral condyle, the first prosthesis is a femoral condyle for connecting the distal end of the femur, the second prosthesis is a tibial support for connecting the proximal end of the tibia, and the intermediate body is a tibial pad between the femoral condyle and the tibial support. When the movable joint prosthesis is an ankle joint prosthesis, the first prosthesis is a talus component for connecting the proximal end of the talus, the second prosthesis is a tibia component for connecting the distal end of the tibia, and the intermediate body is a spacer component between the talus component and the tibia component.

15. A movable joint prosthesis, characterized in that, Include: The first prosthesis is used to connect to the first end of the first bone. The second prosthesis is used to connect to the second end of the second bone. An intermediate body is located between the first prosthesis and the second prosthesis; The friction surface of the first prosthesis can move on the first friction surface of the intermediate body it contacts; The second friction surface of the intermediate is a first convex surface; The friction surface of the second prosthesis is the first concave surface; The second friction surface of the intermediate can move on the friction surface of the second prosthesis that is in contact with it; The mounting surface of the second prosthesis is used to make close contact with the osteotomy surface at the second end of the second bone; the mounting surface is a second convex surface and the osteotomy surface is a second concave surface.

16. The movable joint prosthesis as described in claim 15, characterized in that, The friction surface of the first prosthesis is the third convex surface; the first friction surface of the intermediate body is the third concave surface. The radius of the first convex surface is not greater than the radius of the first concave surface; The first convex surface has a single radius, or the first convex surface has multiple radii, and at least one of the radii is different from the other radii of the first convex surface; The first concave surface has a single radius, or the first concave surface has multiple radii, and at least one of the radii is different from the other radii of the first concave surface; The radius of the second convex surface is not greater than the radius of the second concave surface; The second convex surface has a single radius, or the second convex surface has multiple radii, and at least one of the radii is different from the other radii of the second convex surface; The second concave surface has a single radius, or the second concave surface has multiple radii, and at least one of the radii is different from the other radii of the second concave surface.

17. The movable joint prosthesis as described in claim 15, characterized in that, The first prosthesis applies a first component force in the positive Z direction to the second prosthesis via the intermediate body, and the second prosthesis provides a fourth component force in the opposite Z direction to the intermediate body, which is opposite to the first component force. When the first prosthesis is in motion, a second component force and a third component force in the positive X and Y directions are applied to the second prosthesis via the intermediate body; the second prosthesis provides a fifth component force and a sixth component force in the opposite X and Y directions to the intermediate body to resist the second component force and the third component force; wherein, the fifth component force and the sixth component force increase as the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis increases, so as to constrain the movement range of the intermediate body; The Z, X, and Y directions are perpendicular to the cross-section, sagittal plane, and coronal plane, respectively.

18. The movable joint prosthesis as described in claim 17, characterized in that, The second prosthesis applies a seventh component force in the positive Z direction to the second bone, and the second bone provides a tenth component force in the opposite Z direction to the second prosthesis, which is opposite to the seventh component force. When the frictional shear force generated by the movement of the intermediate body acts on the second prosthesis, the second prosthesis also provides the second bone with the eighth and ninth component forces in the positive X and Y directions; the second bone provides the second prosthesis with the eleventh and twelfth component forces in the opposite X and Y directions to resist the eighth and ninth component forces; wherein, the eleventh and twelfth component forces increase as the distance in the Z direction between the first designated point of the mounting surface and the first origin of the osteotomy surface increases, so as to prevent the relative movement between the second prosthesis and the second bone and to share the frictional shear force.

19. The movable joint prosthesis as described in claim 18, characterized in that, The greater the distance in the Z direction between the second designated point of the second friction surface of the intermediate body and the second origin of the friction surface of the second prosthesis, the greater the first return force obtained by the intermediate body; the first return force is used to cause the intermediate body to move in the direction of the second origin. The first return force corresponds to the tangential component of the positive Z-direction first component at the first contact point where the second designated point of the second friction surface contacts the friction surface of the second prosthesis; the first return force is minimized when the second designated point contacts the second origin.

20. The movable joint prosthesis as described in claim 19, characterized in that, The greater the Z-direction distance between the first designated point of the mounting surface of the second prosthesis and the first origin of the osteotomy surface of the second bone, the greater the second return force obtained by the second prosthesis. The second return force corresponds to the tangential component of the seventh component of the positive Z-direction force at the second contact point where the first designated point on the mounting surface contacts the osteotomy surface of the second bone, and is used to counteract at least part of the frictional shear force; the second return force is minimal when the first designated point contacts the first origin.

21. The movable joint prosthesis as described in claim 20, characterized in that, The movable joint prosthesis is a synovial joint; The first prosthesis is used to connect the distal end of the first bone; the second prosthesis is used to connect the proximal end of the second bone; the mounting surface of the second prosthesis is the distal mounting surface, which is used to make close contact with the osteotomy surface of the proximal end of the second bone. The first designated point is the farthest endpoint of the mounting surface of the second prosthesis; The first origin is the farthest point of the osteotomy surface of the second bone; The second designated point is the farthest endpoint of the second friction surface of the intermediate body; The second origin is the farthest point of the friction surface of the second prosthesis.

22. The movable joint prosthesis as described in claim 20, characterized in that, The movable joint prosthesis is a synovial joint; The first prosthesis is used to connect the proximal end of the first bone; the second prosthesis is used to connect the distal end of the second bone; the mounting surface of the second prosthesis is a proximal mounting surface, which is used to make close contact with the osteotomy surface of the distal end of the second bone. The first designated point is the nearest endpoint of the mounting surface of the second prosthesis; The first origin is the nearest endpoint of the osteotomy surface of the second bone; The second designated point is the nearest endpoint of the second friction surface of the intermediate body; The second origin is the nearest endpoint of the friction surface of the second prosthesis.

23. The movable joint prosthesis as described in claim 20, characterized in that, When the movable joint prosthesis is applied to a unicompartmental knee prosthesis with medial or lateral condyles, the first prosthesis is a femoral condyle for connecting the distal end of the femur, the second prosthesis is a tibial support for connecting the proximal end of the tibia, and the intermediate body is a tibial pad between the femoral condyle and the tibial support; the first designated point is the farthest end of the distal mounting surface of the tibial support; The first origin point is the farthest point of the proximal osteotomy surface of the tibia; the second designated point is the farthest point of the distal friction surface of the tibial pad. The second origin is the farthest point of the proximal friction surface of the tibial support; When the movable joint prosthesis is an ankle joint prosthesis, the first prosthesis is a talus component for connecting the proximal end of the talus, the second prosthesis is a tibial component for connecting the distal end of the tibia, and the intermediate body is a spacer component between the talus component and the tibial component; the first designated point is the nearest endpoint of the proximal mounting surface of the tibial component. The first origin point is the nearest endpoint of the distal osteotomy surface of the tibia; the second designated point is the nearest endpoint of the proximal friction surface of the pad component. The second origin is the nearest endpoint of the distal friction surface of the tibia.

Images