Unicondylar femoral prosthesis system and unicondylar femoral prosthesis

Abstract

The present invention relates to a unicompartmental femoral prosthesis system and a unicompartmental femoral prosthesis. The unicompartmental femoral prosthesis system includes N unicompartmental femoral prostheses of gradually increasing size, wherein N ≥ 2, and the ratio of the anteroposterior diameter of each unicompartmental femoral prosthesis to the posterior condyle height of the unicompartmental femoral prosthesis increases as the size of the unicompartmental femoral prosthesis increases. The anteroposterior diameter is the maximum length of the unicompartmental femoral prosthesis in the horizontal direction, and the posterior condyle height is the maximum height of the unicompartmental femoral prosthesis in the vertical direction. The above-mentioned unicompartmental femoral prosthesis system is more in line with the human anatomical structure, reduces the problem of insufficient coverage and instability of the distal femur or the posterior femoral condyle, reduces the risk of postoperative pain in patients, and makes patients feel better after surgery.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a unicondylar femoral prosthesis system and a unicondylar femoral prosthesis. Background Art

[0002] Unicompartmental knee replacement uses a tiny incision while preserving the anterior and posterior cruciate ligaments of the knee. It offers advantages such as minimal trauma, rapid recovery, and improved postoperative range of motion. Therefore, unicompartmental knee replacement is widely used in the treatment of unicompartmental osteoarthritis. Unicompartmental knee replacement involves replacing the affected femoral articular surface with a femoral prosthesis and the affected tibial articular surface with a tibial liner, resulting in a new knee joint.

[0003] The design of a unicompartmental femoral prosthesis typically includes the following parameters: the anteroposterior diameter (AP), lateral diameter (ML), posterior condyle height (H), fixation post position, and articular surface radius of curvature. By combining these parameters in a certain relationship from small to large, a set of unicompartmental femoral prostheses with increasing sizes can be created. In traditional unicompartmental femoral prosthesis designs, parameters such as the anteroposterior diameter (AP), lateral diameter (ML), and posterior condyle height (H) increase with the size of the unicompartmental femoral prosthesis to accommodate patients of varying body types. However, traditional unicompartmental femoral prosthesis designs fail to fully consider human anatomy, which can easily lead to inadequate coverage or instability of the distal femur or posterior femoral condyle. Summary of the Invention

[0004] Based on this, it is necessary to provide a unicompartmental femoral prosthesis system and a unicompartmental femoral prosthesis, which are more in line with the human anatomy and avoid insufficient or unstable coverage of the distal femur or the posterior femoral condyle.

[0005] A unicompartmental femoral prosthesis system comprises N unicompartmental femoral prostheses of gradually increasing size, wherein N ≥ 2, and the ratio of the anteroposterior diameter of each unicompartmental femoral prosthesis to the posterior condyle height of the unicompartmental femoral prosthesis increases as the size of the unicompartmental femoral prosthesis increases; wherein the anteroposterior diameter is the maximum length of the unicompartmental femoral prosthesis in the horizontal direction, and the posterior condyle height is the maximum height of the unicompartmental femoral prosthesis in the vertical direction.

[0006] In one embodiment, the ratio of the anteroposterior diameter to the posterior condyle height is in the range of 1.2-1.6.

[0007] In one embodiment, the unicompartmental femoral prosthesis further comprises an overhang, wherein the overhang protrudes from the cortical bone of the posterior femoral condyle of the human body, and the ratio of the difference between the height of the posterior condyle and the height of the overhang on the anterior-posterior diameter ratio increases as the size of the unicompartmental femoral prosthesis increases.

[0008] In one embodiment, the ratio of the difference between the height of the posterior condyle and the height of the overhanging portion to the anterior-posterior diameter is in the range of 1.2-1.6.

[0009] In one embodiment, the ratio of the anteroposterior diameter to the posterior condyle height, or the ratio of the anteroposterior diameter to the difference between the posterior condyle height and the height of the overhanging portion satisfies the following conditions:

[0010] For unicompartmental femoral prostheses with an anteroposterior diameter of 40 mm ≤ AP < 50 mm, the value range is 1.28-1.34; for unicompartmental femoral prostheses with an anteroposterior diameter of 50 mm ≤ AP < 55 mm, the value range is 1.34-1.40; for unicompartmental femoral prostheses with an anteroposterior diameter of 55 mm ≤ AP ≤ 65 mm, the value range is 1.40-1.46.

[0011] In one embodiment, the unicompartmental femoral prosthesis includes an articular surface for cooperating with a tibial pad, the articular surface including a distal articular surface, a posterior condyle articular surface, and a posterior epicondyle articular surface connected in sequence, the curvature radius of the distal articular surface in the sagittal plane is a first curvature radius, the curvature radius of the posterior condyle articular surface in the sagittal plane is a second curvature radius, the curvature radius of the posterior epicondyle articular surface in the sagittal plane is a third curvature radius, and the first curvature radius is greater than the second curvature radius, and the second curvature radius is greater than the third curvature radius.

[0012] In one embodiment, the ratio of the first radius of curvature to the second radius of curvature of the unicompartmental femoral prosthesis is a constant value.

[0013] In one embodiment, a ratio of the first radius of curvature to the second radius of curvature of the unicompartmental femoral prosthesis is in a range of 1.65-1.95.

[0014] In one embodiment, the curvature radius of the articular surface on the coronal plane is a fourth curvature radius, and the fourth curvature radius is equal to the second curvature radius.

[0015] In one embodiment, in the coronal plane direction, the medial height of the front end of the unicompartmental femoral prosthesis is smaller than the lateral height of the front end of the unicompartmental femoral prosthesis.

[0016] In one embodiment, the front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis on the coronal plane, the lowest point coincides with the centerline of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is smaller than the curvature radius of the second articular surface on the coronal plane.

[0017] In one embodiment, the front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis on the coronal plane. The lowest point is offset by a first distance relative to the centerline of the unicompartmental femoral prosthesis toward the outer side of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is equal to the curvature radius of the second articular surface on the coronal plane.

[0018] In one embodiment, the front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis. The lowest point is offset by a second distance relative to the centerline of the unicompartmental femoral prosthesis toward the outer side of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is smaller than the curvature radius of the second articular surface on the coronal plane.

[0019] A unicompartmental femoral prosthesis includes an anteroposterior diameter and a posterior condyle height. The anteroposterior diameter is the maximum length of the unicompartmental femoral prosthesis in the horizontal direction, and the posterior condyle height is the maximum height of the unicompartmental femoral prosthesis in the vertical direction. For a unicompartmental femoral prosthesis with an anteroposterior diameter of 40 mm ≤ AP < 50 mm, the ratio of the anteroposterior diameter to the posterior condyle height is in a range of 1.28-1.34; for a unicompartmental femoral prosthesis with an anteroposterior diameter of 50 mm ≤ AP < 55 mm, the ratio of the anteroposterior diameter to the posterior condyle height is in a range of 1.34-1.40; and for a unicompartmental femoral prosthesis with an anteroposterior diameter of 55 mm ≤ AP ≤ 65 mm, the ratio of the anteroposterior diameter to the posterior condyle height is in a range of 1.40-1.46.

[0020] The above-mentioned unicompartmental femoral prosthesis system is based on the human knee anatomy. By designing the ratio of the anterior-posterior diameter to the posterior condyle height of the unicompartmental femoral prosthesis to increase as the size of the unicompartmental femoral prosthesis increases, the unicompartmental femoral prosthesis is more in line with the human anatomy, reducing the problem of insufficient coverage and instability of the distal femur or posterior femoral condyle, reducing the risk of postoperative pain in patients, and making patients feel better after surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 Schematic diagram of the structure of a unicompartmental femoral prosthesis in the sagittal plane according to one embodiment;

[0024] Figure 2 for Figure 1 Schematic diagram of the structure of the unicondylar femoral prosthesis in the cross-sectional direction shown in;

[0025] Figure 3 is an example table of the anteroposterior diameter, posterior condylar height, and aspect ratio of each unicompartmental femoral prosthesis of a unicompartmental femoral prosthesis system in one embodiment;

[0026] Figure 4 FIG2 is a diagram showing the matching relationship between a unicompartmental femoral prosthesis and a femur according to another embodiment;

[0027] Figure 5 is an example table of the anteroposterior diameter, posterior condylar height, and aspect ratio of each unicompartmental femoral prosthesis of a unicompartmental femoral prosthesis system in another embodiment;

[0028] Figure 6 This is a table showing examples of the curvature radii of each articular surface of a unicompartmental femoral prosthesis according to one embodiment;

[0029] Figure 7 This is an example table of curvature radii of each articular surface of a unicompartmental femoral prosthesis according to another embodiment;

[0030] Figure 8 for Figure 1 Cross-sectional view of the unicondylar femoral prosthesis at section AA shown in FIG;

[0031] Figure 9 is a cross-sectional view of a unicompartmental femoral prosthesis taken along section AA of another embodiment;

[0032] Figure 10 This is a cross-sectional view of a unicompartmental femoral prosthesis according to yet another embodiment, taken along section AA.

[0033] Description of reference numerals:

[0034] 10. Articular surface; 11. Distal articular surface; 12. Posterior condylar articular surface; 13. Posterior epicondylar articular surface; 14. Overhang; 15. First articular surface; 16. Second articular surface; 20. Osteotomy surface; 21. Distal osteotomy surface; 22. Posterior condylar osteotomy surface; 23. Posterior epicondylar osteotomy surface; P1, lowest point; P2, highest point; P3, posterior endpoint; P4, anterior end point. DETAILED DESCRIPTION

[0035] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] In order to better illustrate the technical solution of the present invention, the names of the directions involved in each embodiment are first explained:

[0037] Sagittal plane: refers to the longitudinal section that divides the human body or prosthesis into left and right parts from the front-to-back direction. Among them, the sagittal plane passing through the center of the human body or prosthesis is the median sagittal plane, which divides the human body or prosthesis into two equal parts on the left and right.

[0038] Coronal plane: refers to the longitudinal section that divides the human body or prosthesis into the front and back parts from the left and right directions. This section is perpendicular to the sagittal plane.

[0039] Transverse plane: also known as horizontal plane, is a plane parallel to the ground plane that divides the human body or prosthesis into upper and lower parts. This plane is perpendicular to the coronal plane and sagittal plane.

[0040] Medial: The side relatively close to the midsagittal plane of the human body.

[0041] Lateral: The side relatively away from the midsagittal plane of the human body.

[0042] Anterior side: The side closer to the abdomen in the sagittal plane.

[0043] Posterior: The side closer to the back in the sagittal plane.

[0044] See Figure 1-3 , Figure 1 FIG2 shows a schematic structural diagram of a unicompartmental femoral prosthesis in the sagittal plane according to an embodiment of the present invention. Figure 2 A schematic diagram of the cross-sectional structure of a unicompartmental femoral prosthesis according to an embodiment of the present invention is shown. Figure 3 The table is a comparison of the anteroposterior diameter AP, posterior condyle height H and their ratios of each unicompartmental femoral prosthesis of the unicompartmental femoral prosthesis system in one embodiment of the present invention. Specifically, Figure 3 As shown, the unicondylar femoral prosthesis system of one embodiment of the present application includes a group of unicondylar femoral prostheses with gradually increasing sizes, and the number of unicondylar femoral prostheses in a group of unicondylar femoral prostheses is N, N ≥ 2. Here, the "size" of the unicondylar femoral prosthesis refers to the anteroposterior diameter AP of the unicondylar femoral prosthesis. Figure 3As shown in FIG, in a unicompartmental femoral prosthesis system, the ratio AP / H of the anteroposterior diameter AP of each unicompartmental femoral prosthesis to the posterior condyle height H of the unicompartmental femoral prosthesis increases as the size of the unicompartmental femoral prosthesis increases.

[0045] Specifically, see Figure 1 The unicompartmental femoral prosthesis includes an articular surface 10 for cooperating with a tibial liner. The articular surface 10 includes a distal articular surface 11, a posterior condyle articular surface 12, and a posterior epicondyle articular surface 13, which are sequentially connected from the front to the back. The back of the articular surface 10 is an osteotomy surface 20 for contacting the human femur. The osteotomy surface 20 includes a distal osteotomy surface 21, a posterior condyle osteotomy surface 22, and a posterior epicondyle osteotomy surface 23, which are sequentially connected from the front to the back. The distal osteotomy surface 21 is opposite to the distal articular surface 11, the posterior condyle osteotomy surface 22 is opposite to the posterior condyle articular surface 12, and the posterior epicondyle osteotomy surface 23 is opposite to the posterior epicondyle articular surface 13. The above-mentioned osteotomy surfaces 20 are all planes. When viewed from the sagittal plane, the above-mentioned osteotomy surfaces 20 are all straight lines. The point on the distal articular surface 11 that is most vertically distant from the distal osteotomy surface 21 is the lowest point P1 of the prosthesis. When implanted in a human body, this lowest point P1 corresponds to the lowest point of the prosthesis when the person is standing upright. The endpoint of the posterior epicondylar articular surface 13 is the highest point P2 of the prosthesis. The point on the posterior epicondylar articular surface 13 that is most vertically distant from the posterior epicondylar osteotomy surface 23 is the posterior endpoint P3 of the prosthesis. The endpoint of the distal articular surface 11 is the anterior end point P4 of the prosthesis.

[0046] The center of the arc of the distal articular surface 11 is point C. The vertical direction of the prosthesis is the line connecting the lowest point P1 of the prosthesis and the center point C. The horizontal direction is perpendicular to the vertical direction. The posterior condylar height H of the prosthesis refers to the maximum vertical height of the prosthesis, that is, the distance from the lowest point P1 to the highest point P2 of the prosthesis in the vertical direction. The anteroposterior diameter AP of the prosthesis refers to the maximum horizontal length of the prosthesis, that is, the distance from the posterior end point P3 to the anterior end point P4 of the prosthesis in the horizontal direction.

[0047] Conventional unicompartmental femoral prostheses are designed without fully considering the anatomical characteristics of the ratio of the anteroposterior diameter to the posterior condyle height. Typically, the ratio decreases as the size of the unicompartmental femoral prosthesis changes, or remains nearly constant. However, the applicants of this application, through extensive research on human femoral anatomical data, have discovered that the ratio of the anteroposterior diameter to the posterior condyle height of the femur after surgical osteotomy actually increases as the femur size increases. The unicompartmental femoral prosthesis system of the present application is based on the human knee anatomy. By designing the ratio AP / H of the anteroposterior diameter AP of the unicompartmental femoral prosthesis to the posterior condyle height H to increase as the size of the unicompartmental femoral prosthesis increases, the unicompartmental femoral prosthesis is made more consistent with the human anatomy, reducing the problem of insufficient coverage and instability of the distal femur or posterior femoral condyle, reducing the risk of postoperative pain in patients, and making patients feel better after surgery.

[0048] Further, see Figure 3 ,exist Figure 3 In the table, the units of the anteroposterior diameter AP and posterior condyle height H of the unicompartmental femoral prosthesis are both in mm. The ratio of the anteroposterior diameter AP to the posterior condyle height H of the unicompartmental femoral prosthesis (AP / H) (hereinafter referred to as the aspect ratio) ranges from 1.2 to 1.6, preferably from 1.3 to 1.45. Furthermore, for small-sized unicompartmental femoral prostheses (40 mm ≤ AP < 50 mm), the aspect ratio AP / H ranges from 1.28 to 1.34; for medium-sized unicompartmental femoral prostheses (50 mm ≤ AP < 55 mm), the aspect ratio AP / H ranges from 1.34 to 1.40; and for large-sized prostheses (55 mm ≤ AP ≤ 65 mm), the aspect ratio AP / H ranges from 1.40 to 1.46. Furthermore, for a unicompartmental femoral prosthesis in a unicompartmental femoral prosthesis system, if there is an increment or more sizes of the unicompartmental femoral prosthesis, the ratio of the aspect ratios AP / H of the unicompartmental femoral prosthesis of adjacent sizes should be greater than or equal to the aspect ratio AP / H of the smaller unicompartmental femoral prosthesis and less than or equal to the aspect ratio AP / H of the larger unicompartmental femoral prosthesis.

[0049] Further, see Figure 4 In another embodiment, the unicompartmental femoral prosthesis further includes a cantilever portion 14, which protrudes from the cortical bone of the posterior femoral condyle of the human body. That is, its height exceeds the contact point between the cortical bone of the posterior femoral condyle of the human body and the unicompartmental femoral prosthesis, so that the top of the unicompartmental femoral prosthesis is suspended in the air and does not contact the femur. Specifically, the cantilever portion 14 of the unicompartmental femoral prosthesis is the portion on the posterior condyle of the unicompartmental femoral prosthesis that protrudes from the cortical bone of the posterior femoral condyle of the human body after the unicompartmental femoral prosthesis is installed in the human joint. For further information, see Figure 5 The ratio of the anteroposterior diameter AP to the difference between the height H of the superior posterior condyle and the height L of the overhang 14 increases as the size of the unicondylar femoral prosthesis increases. Figure 4 As shown, the height L of the overhang 14 is the height of the posterior condyle of the unicompartmental femoral prosthesis extending beyond the cortical bone of the posterior condyle of the human femur in the sagittal plane. Preferably, the height L of the overhang 14 increases with the size of the unicompartmental femoral prosthesis. In this embodiment, the ratio of the anteroposterior diameter AP to the difference between the posterior condyle height H and the height L of the overhang 14 is AP / (HL), and the value of AP / (HL) increases with the size of the unicompartmental femoral prosthesis.

[0050] like Figure 5 As shown, in this embodiment, the relationship between the anteroposterior diameter AP and the posterior condyle height H, AP / (HL), ranges from 1.2 to 1.6, and this ratio increases as the size of the unicompartmental femoral prosthesis increases. Furthermore, in this embodiment, the height L of the overhang portion 14 of the unicompartmental femoral prosthesis ranges from 1 mm to 3 mm. By appropriately overhanging the posterior condyle of the unicompartmental femoral prosthesis by 1 mm to 3 mm, and by increasing the overhang height L as the size of the unicompartmental femoral prosthesis increases, it is possible to ensure better connection between the posterior condyle of the unicompartmental femoral prosthesis and the soft tissue, thereby improving the stability of the unicompartmental femoral prosthesis. Preferably, the ratio AP / (HL) ranges from 1.3 to 1.45. Furthermore, for small-sized unicompartmental femoral prostheses (40mm≤AP<50mm, height of overhang 14 L=1mm), the value range of AP / (HL) is 1.28-1.34; for medium-sized unicompartmental femoral prostheses (50mm≤AP<55mm, height of overhang 14 L=2mm), the value range of aspect ratio AP / (HL) is 1.34-1.40; for large-sized prostheses (55mm≤AP≤65mm, height of overhang 14 L=3mm), the value range of AP / (HL) is 1.40-1.46.

[0051] For further information, see Figure 1 The distal articular surface 11 has a first curvature radius R1 in the sagittal plane, the posterior condylar articular surface 12 has a second curvature radius R2 in the sagittal plane, and the posterior epicondylar articular surface 13 has a third curvature radius R3 in the sagittal plane. The first curvature radius R1 is greater than the second curvature radius R2, and the second curvature radius R2 is greater than the third curvature radius R3. By making the second curvature radius R2 greater than the third curvature radius R3 in a unicompartmental femoral prosthesis, the posterior condyle of the unicompartmental femoral prosthesis can be retracted inward and its posterior condyle flexion angle can be increased, thereby improving the range of motion of the joint. Furthermore, by adjusting the third curvature radius R3, the posterior condyle height H can be adjusted, allowing the aspect ratio AP / H of the unicompartmental femoral prosthesis to better conform to the recommended aspect ratio.

[0052] Furthermore, if Figure 6-7As shown, the ratio of the first radius of curvature R1 to the second radius of curvature R2 of the unicompartmental femoral prosthesis is a constant value, that is, the ratio of the first radius of curvature R1 to the second radius of curvature R2 of the unicompartmental femoral prosthesis does not change with the size of the unicompartmental femoral prosthesis. Preferably, the ratio of the first radius of curvature R1 to the second radius of curvature R2 of the unicompartmental femoral prosthesis is in the range of 1.65-1.95. The applicant has found through research that the anatomical characteristics of the human femoral condyle are that the ratio of the distal radius of curvature of the femur in the sagittal plane to the radius of curvature of the posterior condyle of the femur in the sagittal plane ranges from 1.45 to 2.1, and the ratio of the distal radius of curvature of the femur in the sagittal plane to the radius of curvature of the posterior condyle of the femur in the sagittal plane has a poor correlation with the size of the femoral condyle. Therefore, using a fixed value for the ratio of the first radius of curvature R1 to the second radius of curvature R2 of the unicompartmental femoral prosthesis can make the unicompartmental femoral prosthesis more suitable for most patients. Compared with a floating ratio, a unicompartmental femoral prosthesis with a fixed ratio is less likely to have a large matching difference after being implanted in a patient.

[0053] Further, see Figure 2 The radius of curvature of the articular surface 10 in the coronal plane is a fourth radius of curvature R4, and this fourth radius of curvature R4 is equal to the second radius of curvature R2, meaning that the posterior condyle articular surface 12 of the unicondylar femoral prosthesis is spherical. Because the posterior condyle of the femur in a natural knee joint is approximately spherical, the posterior condyle articular surface 12 of the unicondylar femoral prosthesis is designed to have the same radius of curvature in both the sagittal and coronal planes, i.e., R2 = R4. This achieves anatomical reconstruction of the natural knee joint and improves the stability of the articular surface.

[0054] See also Figure 8-10 In the coronal plane, the medial height h1 of the front end of the unicompartmental femoral prosthesis is less than the lateral height h2 of the front end of the unicompartmental femoral prosthesis. By reducing the medial height h1 of the front end of the unicompartmental femoral prosthesis, the front end of the unicompartmental femoral prosthesis is lower than the soft tissue of the articular surface, thereby preventing the unicompartmental femoral prosthesis from colliding with the patella after implantation, thereby improving the patient's postoperative experience. Preferably, the medial height h1 of the front end of the unicompartmental femoral prosthesis is less than 2 mm, preferably 1.5 mm to 1.6 mm.

[0055] Specifically, see Figure 8-10 , taking any cross-section AA (i.e., any coronal cross-section) of the front end of the unicondylar femoral prosthesis as an example for explanation. In one embodiment, the front end of the unicondylar femoral prosthesis includes a first articular surface 15 close to the inner side of the unicondylar femoral prosthesis and a second articular surface 16 close to the outer side of the unicondylar femoral prosthesis. The intersection of the first articular surface 15 and the second articular surface 16 on the coronal plane forms the lowest point O of the unicondylar femoral prosthesis on the AA cross-section. Furthermore, there are many ways to reduce the medial height h1 of the front end of the condylar femoral prosthesis, for example Figure 6 as well as Figure 8As shown, in one embodiment, the lowest point O coincides with the centerline m of the unicompartmental femoral prosthesis, i.e., the offset of the lowest point O relative to the centerline m of the unicompartmental femoral prosthesis toward the outside of the unicompartmental femoral prosthesis is 0. Furthermore, the radius of curvature R5 of the first articular surface 15 on the coronal plane is smaller than the radius of curvature R4 of the second articular surface 16 on the coronal plane. In other words, by reducing the radius of curvature of the first articular surface 15 on the coronal plane, the medial height h1 of the front end of the unicompartmental femoral prosthesis is reduced.

[0056] See also Figure 7 as well as Figure 9 As shown, in another embodiment, the radius of curvature R5 of the first articular surface 15 in the coronal plane is equal to the radius of curvature R4 of the second articular surface 16 in the coronal plane, and the lowest point O is offset by a first distance n1 relative to the centerline m of the unicompartmental femoral prosthesis toward the outside of the unicompartmental femoral prosthesis. Preferably, the first distance n1 decreases as the size of the unicompartmental femoral prosthesis increases. Preferably, the first distance n1 ranges from 1 mm to 1.4 mm. By offsetting the lowest point O by the first distance n1 relative to the centerline m of the unicompartmental femoral prosthesis toward the outside of the unicompartmental femoral prosthesis, the medial height of the front end of the unicompartmental femoral prosthesis is reduced.

[0057] It should be noted that, in other embodiments, the above two embodiments can be combined to reduce the medial height h1 of the front end of the condylar femoral prosthesis. Figure 10 As shown, in one embodiment, the lowest point is offset by a second distance n2 relative to the centerline of the unicompartmental femoral prosthesis toward the outside of the unicompartmental femoral prosthesis, and the curvature radius R5 of the first joint surface 15 on the coronal plane is smaller than the curvature radius R4 of the second joint surface 16 on the coronal plane, thereby achieving a reduction in the medial height h1 of the front end of the unicompartmental femoral prosthesis.

[0058] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

[0060] 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.

[0061] 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.

[0062] 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; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, 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.

[0063] 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.

[0064] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

Claims

1. A unicompartmental femoral prosthesis system, characterized in that: The invention comprises N unicompartmental femoral prostheses of gradually increasing sizes, wherein N is greater than or equal to 2, and the ratio of the anteroposterior diameter of each unicompartmental femoral prosthesis to the posterior condyle height of the unicompartmental femoral prosthesis increases as the size of the unicompartmental femoral prosthesis increases; wherein the anteroposterior diameter is the maximum length of the unicompartmental femoral prosthesis in the horizontal direction, and the posterior condyle height is the maximum height of the unicompartmental femoral prosthesis in the vertical direction; The unicompartmental femoral prosthesis also includes a protruding portion, which protrudes from the cortical bone of the posterior femoral condyle of the human body. The ratio of the difference between the height of the posterior condyle and the height of the protruding portion on the anterior-posterior diameter ratio increases as the size of the unicompartmental femoral prosthesis increases, wherein the height range of the protruding portion is 1mm-3mm.

2. The unicompartmental femoral prosthesis system according to claim 1, characterized in that: The ratio of the anterior-posterior diameter to the posterior condyle height is in the range of 1.2-1.

6.

3. The unicompartmental femoral prosthesis system according to claim 2, characterized in that: The ratio of the difference between the height of the posterior condyle and the height of the overhanging portion to the anterior-posterior diameter is in the range of 1.2-1.

6.

4. The unicompartmental femoral prosthesis system according to claim 3, characterized in that: The ratio of the anteroposterior diameter to the height of the posterior condyle, or the ratio of the anteroposterior diameter to the difference between the height of the posterior condyle and the height of the overhanging portion, satisfies the following conditions: For unicompartmental femoral prostheses with an anteroposterior diameter of 40 mm ≤ AP < 50 mm, the value range is 1.28-1.34; for unicompartmental femoral prostheses with an anteroposterior diameter of 50 mm ≤ AP < 55 mm, the value range is 1.34-1.40; for unicompartmental femoral prostheses with an anteroposterior diameter of 55 mm ≤ AP ≤ 65 mm, the value range is 1.40-1.

46.

5. The unicompartmental femoral prosthesis system according to claim 1, characterized in that: The unicompartmental femoral prosthesis includes an articular surface for cooperating with a tibial pad, the articular surface including a distal articular surface, a posterior condyle articular surface and a posterior epicondyle articular surface connected in sequence, the curvature radius of the distal articular surface in the sagittal plane being a first curvature radius, the curvature radius of the posterior condyle articular surface in the sagittal plane being a second curvature radius, the curvature radius of the posterior epicondyle articular surface in the sagittal plane being a third curvature radius, and the first curvature radius being greater than the second curvature radius, and the second curvature radius being greater than the third curvature radius.

6. The unicompartmental femoral prosthesis system according to claim 5, characterized in that: The ratio of the first radius of curvature to the second radius of curvature of the unicompartmental femoral prosthesis is a constant value.

7. The unicompartmental femoral prosthesis system according to claim 5, characterized in that: The ratio of the first radius of curvature to the second radius of curvature of the unicompartmental femoral prosthesis is in the range of 1.65-1.

95.

8. The unicompartmental femoral prosthesis system according to claim 5, characterized in that: The curvature radius of the joint surface on the coronal plane is a fourth curvature radius, and the fourth curvature radius is equal to the second curvature radius.

9. The unicompartmental femoral prosthesis system according to claim 1, characterized in that: In the coronal plane direction, the medial height of the front end of the unicompartmental femoral prosthesis is smaller than the lateral height of the front end of the unicompartmental femoral prosthesis.

10. The unicompartmental femoral prosthesis system according to claim 9, characterized in that: The front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis on the coronal plane, and the lowest point coincides with the centerline of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is smaller than the curvature radius of the second articular surface on the coronal plane.

11. The unicompartmental femoral prosthesis system according to claim 9, characterized in that: The front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis on the coronal plane. The lowest point is offset by a first distance relative to the centerline of the unicompartmental femoral prosthesis toward the outer side of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is equal to the curvature radius of the second articular surface on the coronal plane.

12. The unicompartmental femoral prosthesis system according to claim 9, characterized in that: The front end of the unicompartmental femoral prosthesis includes a first articular surface close to the inner side of the unicompartmental femoral prosthesis and a second articular surface close to the outer side of the unicompartmental femoral prosthesis. On the coronal plane, the intersection of the first articular surface and the second articular surface on the coronal plane forms the lowest point of the unicompartmental femoral prosthesis on the coronal plane. The lowest point is offset by a second distance relative to the centerline of the unicompartmental femoral prosthesis toward the outer side of the unicompartmental femoral prosthesis, and the curvature radius of the first articular surface on the coronal plane is smaller than the curvature radius of the second articular surface on the coronal plane.

13. A unicompartmental femoral prosthesis, characterized in that: The unicompartmental femoral prosthesis includes an anteroposterior diameter and a posterior condyle height, wherein the anteroposterior diameter is the maximum length of the unicompartmental femoral prosthesis in the horizontal direction, and the posterior condyle height is the maximum height of the unicompartmental femoral prosthesis in the vertical direction. For a unicompartmental femoral prosthesis with an anteroposterior diameter of 40 mm ≤ AP < 50 mm, the ratio of the anteroposterior diameter to the posterior condyle height is in the range of 1.28-1.34; for a unicompartmental femoral prosthesis with an anteroposterior diameter of 50 mm ≤ AP < 55 mm, the ratio of the anteroposterior diameter to the posterior condyle height is in the range of 1.28-1.

34. The ratio range is 1.34-1.40; for a unicompartmental femoral prosthesis with an anteroposterior diameter of 55mm≤AP≤65mm, the ratio of the anteroposterior diameter to the posterior condyle height ranges from 1.40 to 1.46; the unicompartmental femoral prosthesis also includes a protruding portion, which protrudes from the cortical bone of the posterior condyle of the human femur. The ratio of the anteroposterior diameter to the difference between the height of the posterior condyle and the height of the protruding portion increases as the size of the unicompartmental femoral prosthesis increases, and the height range of the protruding portion is 1mm-3mm.

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