Unicompartmental knee prosthesis

Abstract

An embodiment of the present invention provides a unicompartmental knee prosthesis. The unicompartmental knee prosthesis includes a liner and a tibial prosthesis. The liner has a first convex surface along its thickness direction; the tibial prosthesis includes a main body, and the main body is provided with a first concave surface on the side facing the liner. The first concave surface and the first convex surface of the liner can be rotatably and slidably matched. The thickness of the inner front edge of the main body is h1; the thickness of the outer edge of the main body is h2, and the thickness of the inner rear edge of the main body is h3, wherein h1>h2>h3. Therefore, the unicompartmental knee prosthesis of the embodiment of the present invention has the advantages of high installation efficiency and reduced risk of product dislocation.

Description

Technical Field

[0001] The present invention relates to the technical field of orthopedic implants, and in particular to a unicompartmental knee joint prosthesis. Background Art

[0002] Knee diseases such as osteoarthritis affect the quality of life of millions of people worldwide. Unicompartmental knee replacements provide greater range of motion and higher patient satisfaction. There are two main types of unicompartmental knee prostheses: mobile and fixed. The fixed-platform unicompartmental knee prosthesis uses a fixed tibial prosthesis and liner, relying on the coordination between the femoral prosthesis and the liner. However, this type of prosthesis can cause problems such as dislocation and limited range of motion. Compared with the fixed-platform unicompartmental knee prosthesis, the mobile unicompartmental knee prosthesis has an additional sliding joint surface, which can easily cause misalignment of the femoral and tibial centerlines during installation. Mobile-platform unicompartmental knee surgery requires higher surgical skills from the surgeon and is less user-friendly for novice surgeons. Misalignment of the femoral and tibial centerlines can lead to phenomena such as meniscus liner rotation and impact, increasing the risk of injury to the patient. Summary of the Invention

[0003] The present invention aims to at least partially address one of the technical problems in the related art. To this end, embodiments of the present invention provide a unicompartmental knee prosthesis. This unicompartmental knee prosthesis has the advantages of high installation efficiency and reduced risk of dislocation.

[0004] A unicompartmental knee prosthesis according to an embodiment of the present invention includes a liner and a tibial prosthesis.

[0005] The liner has a first downwardly convex surface along its thickness. The tibial prosthesis includes a main body, a first downwardly concave surface provided on a side of the main body facing the liner. The first downwardly concave surface (it is understood that the edge of the outer peripheral contour of the first downwardly concave surface is a convex structure) is rotatably and slidably engaged with the first downwardly convex surface of the liner. The thickness of the inner anterior edge of the main body is h1; the thickness of the outer edge of the main body is h2; and the thickness of the inner posterior edge of the main body is h3, wherein h1>h2>h3. Specifically, the side of the main body opposite the first downwardly concave surface is a positioning plane. h1 is the distance between the anterior edge of the first downwardly concave surface of the tibial prosthesis and the positioning plane; h2 is the distance between the outer edge of the first downwardly concave surface of the tibial prosthesis and the positioning plane; and h3 is the distance between the posterior edge of the first downwardly concave surface of the tibial prosthesis and the positioning plane, wherein h1>h2>h3.

[0006] The unicompartmental knee prosthesis of the embodiment of the present invention can better determine the installation position of the pad by relying on the concave surface of the tibial prosthesis by limiting the height of the convexity of the edge of the first concave surface in each direction, and can make the concave surface of the first concave surface automatically coordinate with the convex surface of the first convex surface, thereby improving the efficiency of installation. The concave surface may make the pad easier to place and more intuitive when adjusting the position, thereby shortening the operation time and reducing the risk of intraoperative complications.

[0007] At the same time, the alignment of the first concave surface of the tibial prosthesis with the first convex surface of the liner prevents the liner from rotating out and colliding during installation due to misalignment between the center of the femoral prosthesis or femur and the centerline of the tibial prosthesis. This allows for a wider range of joint motion, improving patient comfort and mobility, and resulting in better adaptability, fit, and stability. Furthermore, the alignment of the first concave surface of the tibial prosthesis with the first convex surface of the liner allows the prosthesis to automatically follow its position after implantation, thereby avoiding the risk of dislocation.

[0008] Furthermore, by ensuring that the thickness of the medial anterior edge (h1) is greater than the thickness of the lateral edge (h2) and greater than the thickness of the medial posterior edge (h3), the risk of dislocation caused by a too-small anterior height is avoided, as well as the problem of motion interference and a reduced maximum flexion angle caused by an excessively high medial posterior thickness. This further enhances stability and patient comfort in this unicondylar knee prosthesis.

[0009] Therefore, the unicompartmental knee joint prosthesis according to the embodiment of the present invention has the advantages of high installation efficiency and reduced risk of dislocation of the product.

[0010] In some embodiments, the tibial prosthesis further includes a stopper arranged in the up-down direction, the stopper being vertically connected to the inner side of the main body, and the liner being capable of abutting against the stopper.

[0011] In some embodiments, the first concave surface has a curvature radius R1 on the inner front side of the main body and a curvature radius R2 on the inner rear side of the main body, and R1 is greater than R2.

[0012] In some embodiments, the R1 is 65.35 mm-71.44 mm.

[0013] In some embodiments, the R2 is 38.54 mm-46.69 mm.

[0014] In some embodiments, the h1 is 9.08 mm-10.88 mm, the h2 is 7.06 mm-7.86 mm, and the h3 is 4.51 mm-5.51 mm.

[0015] In some embodiments, a radius of the first concave surface on the outer side of the main body is R3, and R3 is 67.2 mm-73.05 mm.

[0016] In some embodiments, the unicompartmental knee prosthesis further comprises a femoral prosthesis, wherein the femoral prosthesis is disposed at an end of the femur close to the tibia, and a second downwardly convex surface is disposed on a side of the femoral prosthesis facing the liner.

[0017] In some embodiments, the liner is provided with a second concave curved surface on a side away from the first convex curved surface, which is rotatably and slidably matched with the second convex curved surface.

[0018] In some embodiments, the second concave surface of the pad has a front highest point A, a rear highest point B and an outer highest point C, and the pad has a lowest point D on the first convex surface, the vertical distance between A and D is H1, the vertical distance between C and D is H2, and the vertical distance between B and D is H3, wherein H1>H2>H3.

[0019] In some embodiments, H1 is 10.07 mm-11.87 mm.

[0020] In some embodiments, H2 is 8.01 mm-9.21 mm.

[0021] In some embodiments, H3 is 7.93 mm-8.93 mm.

[0022] In some embodiments, the liner has a second concave curved surface along its thickness direction opposite to the first convex curved surface, the second concave curved surface includes an inner side surface and an outer side surface of the liner that are oppositely disposed, the inner side surface of the liner having a single radius R4 in a cross section parallel to the sagittal plane, 52.72 mm < R4 < 60.23 mm, and a central angle range of 219.37° ≤ δ ≤ 228.24°; the outer side surface of the liner having a gradually varying radius in a cross section parallel to the sagittal plane;

[0023] In some embodiments, the curvature range of the front end, middle end and rear end of the second concave surface is R8.6mm≤δ≤R24.1mm.

[0024] In some embodiments, the inner side of the first downward convex surface has a single radius R5 in a section parallel to the sagittal plane, 51.2mm<R5<59.3mm, and the outer side of the first downward convex surface has a gradual radius in a section parallel to the sagittal plane, and the radius range is 54.7mm<R6<65.4mm.

[0025] In some embodiments, the corresponding sizes of the pad and the tibial prosthesis are such that, when the human body is in a standing position, the difference between the outer peripheral contours of the pad and the tibial prosthesis is 0; and when the human body is in a flexed state, the difference between the anterior outer contours of the pad and the tibial prosthesis is between 0-13.1 mm, the difference between the posterior outer contours is between 0-10.5 mm, and the difference between the lateral outer contours is between 0-12.9 mm.

[0026] In some embodiments, the second concave surface includes multiple arcs along a direction from inside to outside, and the curvature radius of the multiple arcs increases along the direction from inside to outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 1 is a perspective view of a unicompartmental knee prosthesis formed by a femoral prosthesis, a liner, and a tibial prosthesis according to an embodiment of the present invention.

[0028] Figure 2 yes Figure 1 Exploded diagram.

[0029] Figure 3 FIG. 1 is a perspective view of a unicompartmental knee prosthesis formed by a liner and a tibial prosthesis according to an embodiment of the present invention.

[0030] Figure 4 FIG. 1 is another perspective view of a liner and a tibial prosthesis forming a unicompartmental knee prosthesis according to an embodiment of the present invention.

[0031] Figure 5 1 is a front view of a liner and a tibial prosthesis forming a unicondylar knee prosthesis according to an embodiment of the present invention.

[0032] Figure 6 is a lateral view of a liner and tibial prosthesis forming a unicondylar knee prosthesis according to an embodiment of the present invention.

[0033] Figure 7 1 is a cross-sectional view of a liner and a tibial prosthesis according to an embodiment of the present invention.

[0034] Figure 8 1 is a cross-sectional view of a liner and a tibial prosthesis according to an embodiment of the present invention from another direction.

[0035] Figure 9 1 is a schematic structural diagram of a front view of a liner and a tibial prosthesis according to an embodiment of the present invention.

[0036] Figure 10 yes Figure 9 Cross-sectional view along the AA direction.

[0037] Figure 11 yes Figure 9 Cross-sectional view along direction BB.

[0038] Figure 124 is a three-dimensional diagram of a tibial prosthesis according to an embodiment of the present invention.

[0039] Figure 13 is another stereoscopic view of a tibial prosthesis according to an embodiment of the present invention.

[0040] Figure 14 4 is a top view of a tibial prosthesis according to an embodiment of the present invention.

[0041] Figure 15 yes Figure 14 Cross-sectional view along CC direction.

[0042] Figure 16 yes Figure 14 Cross-sectional view along DD direction.

[0043] Figure 17 is a perspective view of a gasket according to an embodiment of the present invention.

[0044] Figure 18 is another perspective view of a gasket according to an embodiment of the present invention.

[0045] Figure 19 is a top view of a gasket according to an embodiment of the present invention.

[0046] Figure 20 4 is a perspective view of a femoral prosthesis according to an embodiment of the present invention.

[0047] Reference numerals:

[0048] Tibial prosthesis 1; main body 11; inner front edge 111; outer edge 112; inner rear edge 113; first concave surface 114;

[0049] a stopper 12;

[0050] Pad 2; first convex surface 21; second concave surface 22; front highest point A201; rear highest point B202; outer highest point C203; lowest point D204; pad inner side 205; pad outer side 206;

[0051] Femoral prosthesis 3; second inferior convex surface 31. DETAILED DESCRIPTION

[0052] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0053] Reference below Figures 1-20 A unicompartmental knee prosthesis according to an embodiment of the present invention is described.

[0054] The unicompartmental knee prosthesis according to the embodiment of the present invention includes a liner 2 and a tibial prosthesis 1 .

[0055] The pad 2 has a first downward convex surface 21 along its thickness direction; the tibial prosthesis 1 includes a main body 11, and a first downward concave surface 114 is provided on the side of the main body 11 facing the pad 2. The first downward concave surface 114 (it can be understood that the edge of the outer peripheral contour of the first downward concave surface 114 is a convex structure) is rotatably and slidably matched with the first downward convex surface 21 of the pad 2, and the thickness of the inner front edge 111 of the main body 11 is h1; the thickness of the outer edge 112 of the main body 11 is h2, and the thickness of the inner rear edge 113 of the main body 11 is h3, wherein h1>h2>h3. Specifically, the side of the main body 11 opposite to the first concave surface 114 is a positioning plane, h1 is the distance between the front edge of the first concave surface 114 of the tibial prosthesis 1 and the positioning plane; h2 is the distance between the outer edge 112 of the first concave surface 114 of the tibial prosthesis 1 and the positioning plane, and h3 is the distance between the rear edge of the first concave surface 114 of the tibial prosthesis 1 and the positioning plane, wherein h1>h2>h3.

[0056] The unicompartmental knee prosthesis of the embodiment of the present invention can better determine the installation position of the pad 2 by relying on the first concave surface 114 of the tibial prosthesis 1 by limiting the height of the convexity of the edge of the first concave surface 114 in various directions. The concave surface of the first concave surface 114 can be automatically matched with the convex surface of the first convex surface 21, thereby improving the efficiency of installation. The concave surface may make the pad 2 easier to place and more intuitive when adjusting the position, which can shorten the operation time and reduce the risk of intraoperative complications.

[0057] At the same time, because the first concave surface 114 of the tibial prosthesis 1 cooperates with the first convex surface 21 of the pad 2, the problem of the pad 2 rotating out and colliding due to the inconsistency between the center of the femoral prosthesis 3 or the femur and the center line of the tibial prosthesis 1 during installation is avoided, allowing the joint to move in a wider range, thereby improving the patient's comfort and exercise ability, and thus having better adaptability, matching and stability. Moreover, the first concave surface 114 of the tibial prosthesis 1 cooperates with the first convex surface 21 of the pad 2, and can automatically follow the reduction after the prosthesis is implanted, thereby avoiding the risk of dislocation.

[0058] The unicompartmental knee prosthesis of this embodiment of the present invention utilizes a thickness h1 of the medial anterior edge 111 greater than the thickness h2 of the lateral edge 112, which is greater than the thickness h3 of the medial posterior edge 113. This effectively avoids the risk of dislocation caused by a too-small anterior height and also avoids the problem of motion interference and a reduced maximum flexion angle caused by excessive thickness of the lateral edge 112 and the medial posterior edge 113. Consequently, this unicompartmental knee prosthesis offers the advantages of further improved stability and patient comfort.

[0059] Therefore, the unicompartmental knee joint prosthesis according to the embodiment of the present invention has the advantages of high installation efficiency and reduced risk of dislocation of the product.

[0060] like Figure 2 、 Figure 2 as well as Figure 12 As shown, the tibial prosthesis 1 further includes a stopper 12 arranged in the vertical direction. The stopper 12 is vertically connected to the inner side of the main body 11, and the liner 2 can abut against the stopper 12. The stopper 12 can limit the range of relative movement of the liner 2, thereby further preventing dislocation of the movable liner, improving the stability of the unicompartmental knee prosthesis, and reducing the risk of injury to the surgical patient.

[0061] Optionally, Figure 13 As shown, the first concave surface 114 includes multiple arc-shaped surfaces in the areas near the front side, the rear side and the outer side.

[0062] The unicompartmental knee prosthesis of the present invention employs multiple curved sections near the outer edge of the first concave surface 114. This not only prevents a sense of catching when sliding relative to the liner 2, but also prevents the liner 2 from dislodging from the first concave surface 114, providing a more natural range of motion and enhancing the user experience. Furthermore, the curved concave surface of the first concave surface 114 increases the contact area with the tibial prosthesis 1, resulting in more even load distribution. The smooth curved surface helps reduce friction between the tibial prosthesis 1 and the liner 2, thereby lowering the wear rate. This not only extends the service life of the unicompartmental knee prosthesis but also reduces the generation of microparticles (which could potentially cause reactions or inflammation in surrounding tissues).

[0063] The first concave curved surface 114 has a radius R1 on the inner front side of the main body 11 and a radius R2 on the inner rear side, with R1 being greater than R2. The larger anterior curvature helps guide the patella (knee) for more natural movement, reducing the risk of patellar dislocation or subluxation. The greater R1 than R2 improves patient comfort and stability during knee flexion. This provides additional anterior-posterior stability support for the knee joint, particularly during activities such as walking and climbing stairs. By optimizing the contact pattern between the liner 2 and the tibial prosthesis 1, a greater flexion angle is achieved, thereby expanding the patient's range of motion.

[0064] like Figure 15 and Figure 16 As shown, the radius R1 of the front arc surface of the first concave curved surface 114 is 65.35mm<R1<71.44mm; and h1 is 9.08mm-10.88mm.

[0065] The unicompartmental knee prosthesis of the embodiment of the present invention, by limiting the radius R1 of the anterior arc surface of the first concave surface 114 and the height h1 of the protruding edge, can, on the one hand, avoid the problem of anterior dislocation of the pad 2 due to h1 and radius R1 being too small, and on the other hand, avoid the range of joint anterior displacement being limited by the radius R1 and the height h1 of the protruding edge being too small.

[0066] Optionally, the radius R1 of the front arc surface of the first concave surface 114 can be 65.35mm, 65.45mm, 65.55mm, 65.65mm, 65.75mm, 65.85mm, 65.95mm, 66.35mm, 66.85mm, 67.35mm, 67.85mm, 68.35mm, 68.85mm, 69.35mm, 69.85mm, 70.35mm, 69.85mm and 71.44mm.

[0067] Optionally, h1 is 9.08mm, 9.18mm, 9.28mm, 9.38mm, 9.48mm, 9.58mm, 9.68mm, 9.78mm, 9.88mm, 9.98mm, 10.08mm, 10.18mm, 10.28mm, 10.38mm, 10.48mm, 10.58mm, 10.68mm, 10.78mm and 10.88mm.

[0068] like Figure 15 and Figure 16 As shown, the radius R2 of the rear arc surface of the first concave curved surface 114 is 38.54 mm<R2<46.69 mm, and h2 is 7.06 mm-7.86 mm.

[0069] The unicompartmental knee prosthesis of the embodiment of the present invention can limit the anterior movement of the joint and prevent the posterior dislocation of the meniscus liner 2 by limiting the radius R2 of the posterior arcuate surface of the first concave curved surface 114 and the height h2 of the protruding edge.

[0070] Optionally, the radius R2 of the rear curved surface of the first concave surface 114 can be 38.54mm, 38.64mm, 38.74mm, 38.84mm, 38.94mm, 39.04mm, 39.54mm, 40.04mm, 40.54mm, 41.04mm, 41.54mm, 42.04mm, 42.54mm, 43.04mm, 43.54mm, 44.04mm, 44.54mm, 45.04mm, 45.54mm, 46.04mm, 46.54mm and 46.69mm.

[0071] Alternatively, h2 can be 7.06 mm, 7.16 mm, 7.26 mm, 7.36 mm, 7.46 mm, 7.56 mm, 7.66 mm, 7.76 mm and 7.86 mm.

[0072] Furthermore, if Figure 15 and Figure 16 As shown, the radius R3 of the outer arc surface of the first concave surface 114 is 67.2mm<R3<73.05mm; and h3 is 4.51mm-5.51mm.

[0073] The unicompartmental knee prosthesis of the embodiment of the present invention can limit joint anterior displacement and prevent lateral dislocation of the meniscus liner 2 by limiting the radius R3 of the outer arc surface of the first concave curved surface 114 and the height h3 of the protruding edge.

[0074] Optionally, the radius R3 of the outer arc surface of the first concave surface 114 can be 67.2 mm, 67.7 mm, 68.2 mm, 68.7 mm, 69.2 mm, 69.7 mm, 70.2 mm, 70.7 mm, 71.2 mm, 71.7 mm, 72.2 mm, 72.7 mm and 73.05 mm.

[0075] Alternatively, h3 may be 4.51 mm, 4.61 mm, 4.51 mm, 4.71 mm, 4.81 mm, 4.91 mm, 5.01 mm, 5.11 mm, 5.21 mm, 5.31 mm, 5.41 mm, and 5.51 mm.

[0076] The unicompartmental knee prosthesis of an embodiment of the present invention also includes a femoral prosthesis 3, which is arranged at one end of the femur close to the tibia. A second downward convex surface 31 is provided on the side of the femoral prosthesis 3 facing the pad 2, and a second downward concave surface 22 is provided on the side of the pad 2 away from the first downward convex surface 21, which can rotate and slide with the second downward convex surface 31.

[0077] The unicompartmental knee prosthesis of the present invention, further comprising a femoral prosthesis 3, allows for simultaneous replacement of worn or necrotic femoral prostheses, thereby improving compatibility between the prosthesis and natural bone and extending the lifespan of the artificial joint. Simultaneous replacement of related components ensures better coordination between components and reduces problems caused by mismatches.

[0078] Alternatively, as Figure 7 and Figure 8As shown, the second concave surface 22 of the pad 2 has a front highest point A201, a rear highest point B202 and an outer highest point C203, and the pad 2 has a lowest point D204 on the first convex surface 21. The vertical distance between A and D is H1, the vertical distance between C and D is H2, and the vertical distance between B and D is H3, wherein H1>H2>H3.

[0079] The unicompartmental knee prosthesis of the present invention, by limiting the convex height around the edge of the second concave surface 22 of the liner 2, allows the liner 2 to better determine the position of the femoral prosthesis 3, thereby preventing the femoral prosthesis 3 from rotating out and colliding due to misalignment of the femoral and tibial centerlines during installation. During installation, the concave surface of the second concave surface 22 automatically aligns with the convex surface of the second convex surface 31, thereby improving installation efficiency. Furthermore, after implantation, the prosthesis automatically returns to its original position, further reducing the risk of dislocation.

[0080] Specifically, H1 is 10.07mm-11.87mm. Thus, by limiting the size of H1, it is possible to avoid H1 being too large, which would cause a reduction in the contact area between the femoral prosthesis 3 and the liner 2, especially when the knee joint is flexed, which would reduce the overall stability of the joint and increase the risk of dislocation. At the same time, it is also possible to avoid H1 being too small, which would limit the maximum flexion angle of the knee joint, thereby affecting the patient's daily activities such as squatting, going up and down stairs, etc. Therefore, the unicompartmental knee prosthesis of the embodiment of the present invention improves the stability of the prosthesis after implantation and increases the flexion angle by reasonably setting the size of H1.

[0081] Alternatively, H1 may be 10.07 mm, 10.17 mm, 10.27 mm, 10.37 mm, 10.47 mm, 10.57 mm, 10.67 mm, 10.77 mm, 10.87 mm, 10.97 mm, 11.07 mm, 11.17 mm, 11.27 mm, 11.37 mm, 11.47 mm, 11.57 mm, 11.67 mm, 11.77 mm, and 11.87 mm.

[0082] Specifically, H2 is 8.01 mm to 9.21 mm. Similarly, the unicompartmental knee prosthesis of the embodiment of the present invention improves the stability of the prosthesis after implantation and increases the flexion angle by reasonably setting the size of H2.

[0083] Alternatively, H2 may be 8.01 mm, 8.11 mm, 8.21 mm, 8.31 mm, 8.41 mm, 8.51 mm, 8.61 mm, 8.71 mm, 8.81 mm, 8.91 mm, 9.01.07 mm, 9.11 mm, and 9.21 mm.

[0084] Specifically, H3 is 7.93 mm to 8.93 mm. Similarly, the unicompartmental knee prosthesis of the embodiment of the present invention improves the stability of the prosthesis after implantation and increases the flexion angle by reasonably setting the size of H3.

[0085] Alternatively, H3 may be 7.93 mm, 8.03 mm, 8.13 mm, 8.23 ​​mm, 8.33 mm, 8.43 mm, 8.53 mm, 8.63 mm, 8.73 mm, 8.83 mm, and 8.93 mm.

[0086] like Figure 8 As shown, the liner 2 has a second concave surface 22 along its thickness, opposite the first convex surface 21. The second concave surface 22 includes an inner side surface 205 and an outer side surface 206, which are disposed opposite each other. The inner side surface 205 has a single radius R4 in a cross section parallel to the sagittal plane, with a central angle range of 219.37°≤δ≤228.24°. The outer side surface 206 has a gradually varying radius in a cross section parallel to the sagittal plane. It should be noted that the single radius is a preset value, meaning that the radius of the inner side surface 205 in a cross section parallel to the sagittal plane remains constant, while the gradually varying radius indicates that the curvature gradually changes from one end to the other.

[0087] The unicompartmental knee prosthesis of the embodiment of the present invention, by limiting the range of the single radius R4, avoids the value of the single radius R4 being too large, which may lead to a reduction in the contact area between the femoral prosthesis 3 and the liner 2, especially when the knee joint is flexed and rotated, thereby reducing the stability and support force of the joint. R4 that is too small may cause a mismatch between the prosthesis and the natural bone structure, thereby affecting the overall biomechanical properties, which is not conducive to the patient's recovery and the durability of the prosthesis in the long run. In addition, a smaller radius of curvature may limit the maximum flexion angle of the knee joint, affecting the patient's daily activities such as squatting, climbing stairs, etc., and reducing the quality of life.

[0088] The lateral surface 206 of the liner is designed with a tapered radius parallel to the sagittal plane. This tapered radius design better adapts to the shape and motion trajectory of the femoral prosthesis 3, achieving a biomimetic, fully conforming design and maintaining a large contact area at various flexion angles. The tapered radius design of the femoral prosthesis 3 and liner 2 not only optimizes joint functionality but also provides enhanced support and stability at different knee joint positions, improving patient comfort.

[0089] The curvature range of the front end, the middle end and the rear end of the projection of the second concave curved surface 22 on the horizontal plane is 8.6≤δ≤24.1.

[0090] The unicompartmental knee prosthesis of the present invention, by limiting the radius of curvature at the edge of the liner 2, prevents an excessively large radius of curvature, which would reduce the contact area between the femoral prosthesis 3 and the liner 2, thereby lowering the overall stability of the joint and increasing the risk of dislocation or subluxation. It also prevents an excessively small radius of curvature, which could limit the maximum flexion angle of the knee joint, affecting daily activities such as squatting and climbing stairs, and reducing the patient's quality of life.

[0091] δ can be 8.6mm, 9.6mm, 10.6mm, 11.6mm, 12.6mm, 13.6mm, 14.6mm, 15.6mm, 16.6mm, 17.6mm, 18.6mm, 19.6mm, 20.6mm, 21.6mm, 22.6mm, 23.6mm and 24.1mm.

[0092] like Figure 18 As shown, the inner side of the first downward convex surface 21 in the section parallel to the sagittal plane has a single radius R5, 51.2mm<R5<59.3mm, and the outer side of the first downward convex surface 21 in the section parallel to the sagittal plane has a gradual radius, and the radius range is 54.7mm<R6<65.4mm.

[0093] Optionally, R5 can be 51.2mm, 52.2mm, 53.2mm, 54.2mm, 55.2mm, 56.2mm, 57.2mm, 58.2mm, or 59.2mm.

[0094] Alternatively, R6 can be 54.7mm, 55.7mm, 56.7mm, 57.7mm, 58.7mm, 59.7mm, 60.7mm, 61.7mm, 62.7mm, 63.7mm and 64.7mm.

[0095] In this embodiment, by setting the inner side of the first downward convex surface 21 to a single radius in the section parallel to the sagittal plane and the outer side to a gradual radius in the section parallel to the sagittal plane, a bionic structural design can be achieved, which is consistent with the ergonomic structure, thereby reducing the wear between the tibial prosthesis 1 and the pad 2, achieving automatic follow-up reduction between the pad 2 and the tibial prosthesis 1, providing a better fit, and maintaining joint stability at different flexion angles.

[0096] Alternatively, as Figure 20As shown, the second concave curved surface 22 comprises multiple arcs extending from the inside to the outside, with the radius of curvature of each arc increasing from the inside to the outside. It can be understood that the second concave curved surface 22 is a downwardly concave pit structure defined on the upper surface of the liner 2. Therefore, the sidewalls of the pit are all curved, but the diameter of the pit gradually decreases from top to bottom. Therefore, the radius of curvature of the arc projected from the top to bottom of the sidewalls of the pit gradually increases from the inside to the outside. As is well known, the anatomical shape of the human meniscus liner is concave and circumferentially resembles an annual ring. This arrangement ensures the biomimetic structural design of the liner 2, thereby providing improved adaptability.

[0097] Optionally, the corresponding dimensions of the pad 2 and the tibial prosthesis 1 are such that, when the human body is standing, the difference between the outer peripheral contours of the pad 2 and the tibial prosthesis 1 is 0; and when the human body is flexed, the difference between the anterior outer contours of the pad 2 and the tibial prosthesis 1 is between 0-13.1 mm, the difference between the posterior outer contours is between 0-10.5 mm, and the difference between the lateral outer contours is between 0-12.9 mm.

[0098] The unicompartmental knee prosthesis of the present invention limits the difference in the outer contours of the liner 2 and the anterior, posterior, and lateral sides of the tibial prosthesis 1 when the body is flexed. Excessive differences can lead to a significant gap or misalignment between the first lower concave surface 114 of the tibial prosthesis 1 and the first lower convex surface 21 of the liner 2, resulting in reduced contact area and motion interference. This can lead to localized stress concentration or interference, especially during high-load activities (such as walking or climbing stairs), increasing the risk of wear and limiting the maximum flexion angle of the knee joint. By limiting the difference in the outer contours of the liner 2 and the tibial prosthesis 1, the unicompartmental knee prosthesis of the present invention has the advantages of enhancing the patient's freedom of movement and extending its service life.

[0099] Furthermore, in the flexed state of the human body, the differences in the anterior outer contours of the liner 2 and the tibial prosthesis 1 are 0, 1.1 mm, 2.1 mm, 3.1 mm, 4.1 mm, 5.1 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm and 13.1 mm.

[0100] The rear outer contour difference is 0, 0.5mm, 1.5mm, 2.5mm, 3.5mm, 4.5mm, 5.5mm, 6.5mm, 7.5mm, 8.5mm, 9.5mm and 10.5mm. The outer contour difference is 0, 0.9mm, 1.9mm, 2.9mm, 3.9mm, 4.9mm, 5.9mm, 6.9mm, 7.9mm, 8.9mm, 9.9mm, 10.9mm, 11.9mm and 12.9mm.

[0101] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0102] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0103] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0104] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0105] In the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0106] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A unicompartmental knee prosthesis, characterized in that: include: a liner having a first downwardly convex surface along a thickness direction thereof; A tibial prosthesis comprising a main body, wherein a first concave surface is provided on a side of the main body facing the liner, the first concave surface being rotatably and slidably engaged with the first convex surface of the liner, the thickness of the inner front edge of the main body being h1; the thickness of the outer edge of the main body being h2; and the thickness of the inner rear edge of the main body being h3, wherein h1>h2>h3; The first concave curved surface has a curved surface radius R1 on the inner front side of the main body and a curved surface radius R2 on the inner rear side of the main body, and R1 is larger than R2; The pad is provided with a second concave surface on the side away from the first convex surface. The second concave surface of the pad has a front highest point A, a rear highest point B and an outer highest point C. The pad has a lowest point D on the first convex surface. The vertical distance between A and D is H1, the vertical distance between C and D is H2, and the vertical distance between B and D is H3, wherein H1>H2>H3.

2. The unicompartmental knee prosthesis according to claim 1, wherein: The tibial prosthesis further includes a stopper arranged in the up-down direction, the stopper being vertically connected to the inner side of the main body, and the liner being capable of abutting against the stopper.

3. The unicompartmental knee prosthesis according to claim 2, characterized in that: The R1 is 65.35mm-71.44mm, and / or the R2 is 38.54mm-46.69mm.

4. The unicompartmental knee prosthesis according to claim 1, wherein: The h1 is 9.08mm-10.88mm, the h2 is 7.06mm-7.86mm, and the h3 is 4.51mm-5.51mm.

5. The unicompartmental knee prosthesis according to claim 2, characterized in that: The radius of the first concave surface on the outer side of the main body is R3, and R3 is 67.2 mm-73.05 mm.

6. The unicompartmental knee prosthesis according to claim 1, characterized in that: It also includes a femoral prosthesis, which is arranged at one end of the femur close to the tibia, and a second lower convex surface is arranged on the side of the femoral prosthesis facing the liner. The second concave curved surface and the second convex curved surface are rotatably and slidably matched.

7. The unicompartmental knee prosthesis according to claim 6, characterized in that: H1 is 10.07mm-11.87mm, and / or; H2 is 8.01mm-9.21mm; and / or H3 is 7.93mm-8.93mm.

8. The unicompartmental knee prosthesis according to claim 1, wherein: The second concave curved surface includes an inner side surface and an outer side surface of the pad that are oppositely disposed. The inner side surface of the pad has a single radius R4 in a cross section parallel to the sagittal plane, 52.72 mm < R4 < 60.23 mm, and a central angle range of 219.37° ≤ δ ≤ 228.24°. The outer side surface of the pad has a gradually varying radius in a cross section parallel to the sagittal plane. And / or, the curvature range of the front end, middle end and rear end of the second concave curved surface is 8.6 mm ≤ δ ≤ 24.1 mm; And / or, the inner side of the first downward convex surface has a single radius R5 in a section parallel to the sagittal plane, 51.2mm<R5<59.3mm, and the outer side of the first downward convex surface has a gradual radius R6 in a section parallel to the sagittal plane, 54.7mm<R6<65.4mm.

9. The unicompartmental knee prosthesis according to any one of claims 1 to 8, characterized in that: The dimensions of the liner and the tibial prosthesis are such that, in a standing position, the difference between the outer contours of the liner and the tibial prosthesis is 0; and in a flexed position, the difference between the anterior outer contour of the liner and the tibial prosthesis is 0-13.1 mm, the difference between the posterior outer contour of the liner and the tibial prosthesis is 0-10.5 mm, and the difference between the lateral outer contour of the liner and the tibial prosthesis is 0-12.9 mm. And / or, the second concave curved surface includes multiple arcs along the direction from the inside to the outside, and the curvature radius of the multiple arcs increases along the direction from the inside to the outside.

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