CN113040979A - Knee joint prosthesis - Google Patents

Abstract

The invention relates to a knee joint prosthesis, wherein the knee joint prosthesis comprises a tibia prosthesis and a femur prosthesis, wherein the tibia prosthesis comprises a tibia joint surface used for replacing a damaged tibia and a stand column arranged on the tibia joint surface. The femoral prosthesis comprises a medial condyle articular surface, a lateral condyle articular surface and a cam, wherein the medial condyle articular surface and the lateral condyle articular surface are arranged at intervals, and the cam is connected with the medial condyle articular surface and the lateral condyle articular surface. Referring to the figure, the section of the cam on the sagittal plane forms a first straight line segment and an oblique line segment which are used for being matched with the upright column, the first straight line segment and the oblique line segment are arranged at an included angle, a first round angle is connected between the first straight line segment and the oblique line segment, and a second round angle is connected at one end, far away from the first round angle, of the oblique line segment. The knee joint prosthesis reduces the dislocation and dislocation probability of the femoral prosthesis and the tibial prosthesis, increases the stability of the knee joint prosthesis and reduces the revision rate of the knee joint prosthesis.

Description

Knee joint prosthesis

Technical Field

The invention relates to the technical field of medical instruments, in particular to a knee joint prosthesis.

Background

With the improvement of surgical techniques and knee prostheses, total knee replacement surgery is becoming more mature. The total knee replacement is an effective treatment means for solving the problem of late-stage arthritis, the posterior stabilized knee prosthesis is an important component of the total knee replacement operation, and the replacement amount of the posterior stabilized knee prosthesis accounts for about half of the total knee replacement according to statistics.

In replacing a posterior stabilized knee prosthesis, it is necessary to resect the anterior and posterior cruciate ligaments of the knee. In the design of conventional posterior stabilized knee prostheses, the cam and post structures are often used to replace the posterior cruciate ligament function in order to achieve the goals of guiding the "rolling motion" of the knee and maintaining the kinematic stability of the knee. However, conventional posterior stabilized prostheses are prone to post-operative dislocation or loosening failure during flexion, particularly at high flexion. And conventional posterior stabilized prostheses do not restore the natural motion of the knee joint well.

Disclosure of Invention

Therefore, the knee joint prosthesis is needed to reduce the probability of dislocation and looseness of the femoral component and the tibial component and prolong the service life of the knee joint prosthesis.

A knee joint prosthesis comprising:

a tibial prosthesis comprising a tibial articular surface and a post disposed on the tibial articular surface; and the number of the first and second groups,

the femur prosthesis comprises a medial condyle joint surface and a lateral condyle joint surface which are arranged at intervals, and a cam for connecting the medial condyle joint surface and the lateral condyle joint surface, wherein the cam is used for being matched with the upright post, a first straight line section facing to a central coronal plane and an oblique line section back to the central coronal plane are formed on the section of the cam on the sagittal plane, the first straight line section and the oblique line section form an included angle, a first round angle is connected between the first straight line section and the oblique line section, and one end, far away from the first round angle, of the oblique line section is connected with a second round angle.

The technical solution of the present application is further described below:

in one embodiment, the included angle between the first straight line segment and the oblique line segment is 0-90 °.

In one embodiment, the cam comprises a first curve and a second curve which are oppositely arranged in a cross section, and the first curve and the second curve are symmetrically arranged relative to the first crown surface.

In one embodiment, the first curve and/or the second curve includes a first arc segment, a second arc segment connecting the first arc segment and the lateral condyle articular surface, and a third arc segment connecting the first arc segment and the medial condyle articular surface, the first arc segment being tangent to the second arc segment and the third arc segment, respectively.

In one embodiment, the center of the first arc segment has a first spacing relative to a central sagittal plane of the femoral prosthesis in a direction proximal to the medial condylar articular surface.

In one embodiment, the radius of curvature of the first circular arc segment is greater than the radius of curvature of the second circular arc segment, and the radius of curvature of the second circular arc segment is greater than the radius of curvature of the third circular arc segment.

In one embodiment, the tibial articular surface comprises an inner supporting surface and an outer supporting surface, the post comprises an inner side surface connected with the inner supporting surface, an outer side surface connected with the outer supporting surface, and a rear side surface connected with the inner side surface and the outer side surface and used for being matched with the cam, the inner side surface and the outer side surface form an included angle, and the distance between the inner side surface and the outer side surface is gradually increased along the direction close to the tibial articular surface.

In one embodiment, the rear side surface includes, in cross section, a fourth arc segment, a fifth arc segment connecting the fourth arc segment with the outer side surface, and a sixth arc segment connecting the fourth arc segment with the inner side surface, and a radius of curvature of the fourth arc segment is smaller than a radius of curvature of the first arc segment; the curvature radius of the fifth circular arc section is smaller than that of the second circular arc section; and the curvature radius of the sixth circular arc section is smaller than that of the third circular arc section.

In one embodiment, the posterior surface includes a fourth arc segment, a fifth arc segment connecting the fourth arc segment with the lateral surface, and a sixth arc segment connecting the fourth arc segment with the medial surface, and a center of the fourth arc segment has a second distance toward a direction close to the lateral support surface with respect to a sagittal plane of a center of the tibial prosthesis.

In one embodiment, the maximum distance of the tibial prosthesis in the front and back direction is AP, the distance from the central position of the upright post to the back end of the tibial prosthesis is L, and L/AP is 0.2-0.5; and/or the maximum distance of the tibial prosthesis in the medial-lateral direction is ML, and the distance from the central position of the upright post to the medial edge of the tibial prosthesis is H, wherein H is ML/2.

According to the knee joint prosthesis, the cam is configured to be in a triangle-like shape design with the first straight line segment, the first round angle, the oblique line segment and the second round angle which are sequentially connected on the sagittal plane, wherein the first round angle, the oblique line segment and the second round angle form a contact area between the cam and the stand column in the buckling process of the knee joint prosthesis, and along with the increase of the buckling angle, the contact position between the stand column and the cam is firstly on the first round angle, then on the oblique line segment and finally on the second round angle, so that the jumping distance of the knee joint prosthesis is gradually increased, the probability of dislocation and dislocation of the femoral prosthesis and the tibial prosthesis is further reduced, the stability of the knee joint prosthesis is increased, and the revision rate of the knee joint prosthesis is reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view of a knee prosthesis according to an embodiment;

FIG. 2 is a schematic structural view of a femoral prosthesis of the knee joint prosthesis shown in FIG. 1;

FIG. 3 is a schematic view of the tibial component of the knee prosthesis shown in FIG. 1;

FIG. 4 is an elevational view of an embodiment of a femoral prosthesis;

FIG. 5 is a cross-sectional view of the femoral prosthesis shown in FIG. 4 in the sagittal plane A-A;

FIG. 6 is a cross-sectional view of the femoral prosthesis shown in FIG. 4 at cross-section B-B;

FIG. 7 is a top view of an embodiment of a tibial prosthesis;

FIG. 8 is a cross-sectional view of the tibial prosthesis shown in FIG. 7 in the sagittal plane D-D;

FIG. 9 is a cross-sectional view of the tibial prosthesis shown in FIG. 7 in coronal plane C-C;

FIG. 10 is a posterior view of the tibial prosthesis shown in FIG. 7;

FIG. 11 is a second top view of the tibial prosthesis shown in FIG. 7;

FIG. 12 is a three-dimensional view of an embodiment of a knee prosthesis at 5 hyperextension;

FIG. 13 is a three-dimensional view of an embodiment of a knee prosthesis in a straightened position;

FIG. 14 is a three-dimensional view of an embodiment of a knee prosthesis at a flexion angle of 30;

FIG. 15 is a three-view illustration of an embodiment of a knee prosthesis at a flexion angle of 60;

FIG. 16 is a three-view illustration of an embodiment of a knee prosthesis at a 75 degree flexion angle;

FIG. 17 is a three-view illustration of an embodiment of a knee prosthesis at a 90 ° flexion angle;

FIG. 18 is a three-dimensional view of an embodiment of a knee prosthesis at a flexion angle of 120;

FIG. 19 is a three-view illustration of an embodiment of a knee prosthesis at a 135 degree flexion angle;

FIG. 20 is a three-view illustration of an embodiment of a knee prosthesis at a flexion angle of 160;

FIG. 21 is a three-dimensional view of an embodiment of a knee prosthesis at an angle of flexion (180-a).

Description of the figures:

10. a femoral prosthesis; 11. the medial condylar articular surface; 12. the lateral condylar articular surface; 13. a cam; 131. a first straight line segment; 132. a first rounded corner; 133. a diagonal segment; 134. a second rounded corner; 135. a second straight line segment; 136. a second curve; 137. a first curve; 1371. a first arc segment; 1372. a second arc segment; 1373. a third arc segment; 14. an accommodation hole; 20. a tibial prosthesis; 21. a column; 211. an inner side surface; 212. an outer side surface; 213. a rear side; 2131. a fourth arc segment; 2132. a fifth arc segment; 2133. a sixth arc segment; 22. an inner support surface; 23. an outer bearing surface; 31. a central sagittal plane; 32. a first coronal plane; 33. a central coronal plane.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

To better explain the technical solutions of the present invention, the terms of orientation in the embodiments are explained first.

Sagittal plane: longitudinally cutting a human body or a joint into a section formed by a left part and a right part;

coronal plane: dividing the human body or the joint into a front section and a rear section, wherein the section is vertical to the sagittal plane;

cross section: dividing the human body or the joint into an upper section and a lower section, wherein the section is vertical to the coronal plane and the sagittal plane;

a far end: the end of the body or joint relatively far from the head;

proximal end: the human body or joint is relatively close to one end of the head;

inner side: relatively close to the sagittal plane of a human body;

outside: relatively deviated from the sagittal plane of the human body;

front side: the side near the chest in the sagittal plane;

rear side: on the side of the sagittal plane near the back.

In particular, an embodiment of the present application provides a knee prosthesis for replacing damaged knee joint facets in a knee replacement procedure to restore normal motion of the knee joint. Specifically, knee joint prostheses are generally classified into left-leg knee joint prostheses for the left leg and right-leg knee joint prostheses for the right leg, wherein the left-leg knee joint prostheses are mirror-symmetrical with the right-leg knee joint prostheses with respect to the sagittal plane. In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, a left knee joint prosthesis applied to a left leg will be described in detail below as an example.

Referring to fig. 1-3, one embodiment of a knee prosthesis includes a tibial prosthesis 20 and a femoral prosthesis 10, where the tibial prosthesis 20 includes a tibial articular surface for replacing a damaged tibia and a post 21 disposed on the tibial articular surface. The femoral prosthesis 10 includes a medial condyle articular surface 11, a lateral condyle articular surface 12, and a cam 13, wherein the medial condyle articular surface 11 and the lateral condyle articular surface 12 are spaced apart, and the cam 13 connects the medial condyle articular surface 11 and the lateral condyle articular surface 12. Referring to fig. 4-5, the section of the cam 13 in the sagittal plane forms a first straight line segment 131 and an oblique line segment 133 for cooperating with the pillar 21, the first straight line segment 131 forms an included angle with the oblique line segment 133, a first round corner 132 is connected between the first straight line segment 131 and the oblique line segment 133, and a second round corner 134 is connected to the end of the oblique line segment 133 away from the first round corner 132. Further, a first straight line segment 131 faces toward the central coronal plane 33 of the femoral prosthesis 10 and a diagonal segment 133 faces away from the central coronal plane 33 of the femoral prosthesis 10, wherein the central coronal plane 33 refers to a coronal plane passing through the anteroposterior centerline of the femoral prosthesis 10, wherein the anteroposterior centerline of the femoral prosthesis 10 refers to a straight line equally dividing the femoral prosthesis 10 into anteroposterior two parts, and equally dividing here refers to equally dividing the anteroposterior maximum length into two parts of equal length.

Specifically, the cam 13 is configured as a triangle-like shape design having a first straight line segment 131, a first rounded corner 132, a diagonal line segment 133, a second rounded corner 134, and a second straight line segment 135 connected in this order on the sagittal plane, wherein the first straight line segment 131 intersects the second straight line segment 135, one end of the diagonal line segment 133 is connected to the first straight line segment 131 through the first rounded corner 132, and the other end of the diagonal line segment 133 is connected to the second straight line segment 135 through the second rounded corner 134. Preferably, the second straight line segment 135 is parallel to the cross section, and the first straight line segment 131 may be perpendicular to the second straight line segment 135 or may not be perpendicular to the second straight line segment 135. Preferably, the first straight line segment 131 is perpendicular to the second straight line segment 135.

Further, the cam 13 is adapted to cooperate with the post 21 in order to complete the flexion movement of the knee prosthesis. Specifically, the medial condyle articular surface 11, the lateral condyle articular surface 12, and the cam 13 collectively enclose a receiving hole 14, and the post 21 is inserted into the receiving hole 14. The medial condyle joint surface 11 and the lateral condyle joint surface 12 are respectively located on both sides of the vertical column 21, and the medial condyle joint surface 11 and the lateral condyle joint surface 12 are in sliding fit with the tibia. In the process of the knee joint prosthesis flexion, the cam 13 is in contact with the upright post 21, and the femoral prosthesis 10 rotates inwards and outwards relative to the tibia with the contact point of the cam 13 and the upright post 21 as a fulcrum, so that the knee joint prosthesis flexion is realized.

In the process of bending of the conventional knee joint prosthesis, particularly when the knee joint prosthesis bends at a large angle, the distance (hereinafter, collectively referred to as a jump distance) from the contact point of the cam 13 and the upright post 21 to the top of the upright post 21 is too small, which can easily cause dislocation of the knee joint prosthesis after operation on one hand, and can increase the shearing force applied by the femoral prosthesis 10 to the tibial prosthesis 20 on the other hand, thereby causing loosening and failure of the knee joint prosthesis.

The knee joint prosthesis of the present application is designed by configuring the cam 13 to have a triangle-like shape having a first straight line segment 131, a first rounded corner 132, a diagonal line segment 133, and a second rounded corner 134 connected in sequence on the sagittal plane, and the first rounded corner 132, the diagonal line segment 133, and the second rounded corner 134 form a contact area between the cam 13 and the pillar 21 during flexion of the knee joint prosthesis. Referring to fig. 12 to 21, as the flexion angle increases, the contact position between the pillar 21 and the cam 13 is firstly on the first rounded corner 132, then on the oblique line section 133, and finally on the second rounded corner 134, so that the jump distance of the knee joint prosthesis is gradually increased, the probability of dislocation and dislocation of the femoral prosthesis 10 and the tibial prosthesis 20 is reduced, the stability of the knee joint prosthesis is increased, and the revision rate of the knee joint prosthesis is reduced. The flexion angle is the angle at which the knee joint is bent, and is 0 at the initial position when the knee joint is extended. Taking the knee prosthesis as an example, the joint surfaces 11 and 12 of the femoral prosthesis 10 face the tibial joint surface, and the flexion angle is 0 degree when the first straight line segment 131 is parallel to the posterior surface 213, and the flexion angle gradually increases when the knee joint performs the flexion motion. The bending angle is an included angle between the first straight line segment 131 and the rear side surface 213.

Further, referring to fig. 5, an angle a between the first straight line segment 131 and the oblique line segment 133 is 0 ° to 90 °, and preferably 20 ° to 70 °. Within the angle range, the flexion stability of the knee joint prosthesis is more facilitated, and the natural motion of the knee joint can be better recovered. As shown in FIGS. 12-21, when the flexion angle is increased from small to (180-a), the contact area of the cam 13 with the post 21 is transformed from line contact to surface contact (S1 in the sagittal plane contact area and S2 in the cross-sectional plane contact area), and (180-a) can be designed to be the maximum flexion angle or the flexion angle with the most wear of the knee prosthesis, so that the contact pressure between the cam 13 and the post 2131 at this time is greatly reduced, thereby reducing the wear of the knee prosthesis.

Referring to fig. 6, the cross section of the cam 13 includes a first curve 137 and a second curve 136 which are oppositely arranged, and the first curve 137 and the second curve 136 are symmetrically arranged relative to the first crown surface. Wherein the first coronal plane refers to a coronal plane passing through a midline of the first curve 137 and the second curve 136.

Further, with continued reference to fig. 6, first curve 137 and/or second curve 136 includes a first arc segment 1371, a second arc segment 1372 connecting first arc segment 1371 with lateral condyle articular surface 12, and a third arc segment 1373 connecting first arc segment 1371 with medial condyle articular surface 11. The first arc segment 1371 is tangent to the second arc segment 1372 and the third arc segment 1373. The section of the cam 13 on the cross section adopts a hyperbolic curve arrangement, which is more favorable for guiding the internal and external rotation movement of the knee joint prosthesis, better recovers the natural movement of the knee joint and ensures that a patient has better proprioception after operation.

Further, the curvature radius of first circular arc section 1371 is greater than the curvature radius of second circular arc section 1372, and the curvature radius of second circular arc section 1372 is greater than the curvature radius of third circular arc section 1373, has improved the matching degree of cam 13 and stand 21 through the design of such curvature radius, has increased the area of contact of cam 13 and stand 21 to knee joint prosthesis's wearing and tearing have been reduced, knee joint prosthesis's life has been improved.

Further, referring to fig. 6, center O of first arc segment 1371 is spaced from central sagittal plane 31 of femoral prosthesis 10. The central sagittal plane 31 is a sagittal plane passing through the medial-lateral center line of the femoral prosthesis 10, wherein the medial-lateral center line of the femoral prosthesis 10 is a straight line equally dividing the femoral prosthesis 10 into the medial and lateral parts, and the equal division means equally dividing the maximum left-right length into the two equal parts. Specifically, the center of first arc segment 1371 has a first spacing L1 toward the proximal medial condyle articular surface relative to the central sagittal plane 31 of femoral prosthesis 10. Preferably, the first distance L1 is greater than 0mm and less than or equal to 2 mm. By providing the center O of the first arc segment 1371 with an eccentricity (i.e., the first distance L1) with respect to the sagittal plane 31 of the femoral prosthesis 10, the internal and external rotation of the knee prosthesis can be guided more easily, the natural motion of the knee can be recovered better, and the patient can have better proprioception after surgery.

Specifically, referring to fig. 7-9, the cross-section of the post 21 in the coronal plane is trapezoidal and the post 21 in the sagittal plane is trapezoidal-like. I.e., toward the proximal tibial articular surface, the post 21 gradually increases in size. Specifically, referring to fig. 10, the tibial articular surface includes a medial bearing surface 22 and a lateral bearing surface 23, wherein the medial bearing surface 22 mates with the medial condyle articular surface 11 and the lateral bearing surface 23 mates with the lateral condyle articular surface 12. Further, the upright 21 comprises an inner side 211 connected to the inner support surface 22, an outer side 212 connected to the outer support surface 23, and a rear side 213 connecting the inner side 211 and the outer side 212 and adapted to cooperate with the cam 13. Referring to fig. 9, the medial surface 211 and the lateral surface 212 are disposed at an angle, and the distance between the medial surface 211 and the lateral surface 212 gradually increases along the direction close to the tibial articular surface. By arranging the inner side surface 211 and the outer side surface 212 to form an included angle and gradually increasing the distance between the inner side surface 211 and the outer side surface 212 along the direction close to the tibial articular surface, the width of the rear side surface 213 can be gradually increased along the direction close to the tibial articular surface, so that in the buckling process of the knee joint prosthesis, along with the increase of the buckling angle, the jump distance between the cam 13 of the femoral prosthesis and the upright post 21 of the tibial prosthesis 20 is gradually increased (namely, the contact point moves downwards), the contact area between the cam 13 and the upright post 21 is also gradually increased, the pressure of the cam 13 and the upright post 21 is reduced, the abrasion between the cam 13 and the upright post 21 is reduced, and the service life of the knee joint prosthesis is prolonged.

Further, referring to fig. 7, the rear side surface 213 includes, in cross section, a fourth arc segment 2131, a fifth arc segment 2132 connecting the fourth arc segment 2131 with the outer side surface 212, and a sixth arc segment 2133 connecting the fourth arc segment 2131 with the inner side surface 211, and both ends of the fourth arc segment 2131 are tangent to the fifth arc segment 2132 and the sixth arc segment 2133, respectively.

Further, the radius of curvature of the fourth arc segment 2131 is smaller than the radius of curvature of the first arc segment 1371; the radius of curvature of the fifth arc segment 2132 is less than the radius of curvature of the second arc segment 1372; sixth arc segment 2133 has a radius of curvature that is less than the radius of curvature of third arc segment 1373. Preferably, the radius of curvature of the fourth circular arc segment 2131 is smaller than the radius of curvature of the first circular arc segment 1371 by 0mm to 1 mm; the radius of curvature of the fifth arc segment 2132 is 0mm to 1mm smaller than the radius of curvature of the second arc segment 1372; the radius of curvature of the sixth arc segment 2133 is 0mm to 1mm smaller than the radius of curvature of the third arc segment 1373. By the design, the contact area of the cam 13 and the upright post 21 is increased, and the wear of the knee joint prosthesis is reduced.

Further, a center N of fourth circle segment 2131 is spaced from central sagittal plane 31 of tibial prosthesis 20. The central sagittal plane of the tibial prosthesis 20 refers to the sagittal plane passing through the medial and lateral centerlines of the tibial prosthesis 20. The medial-lateral centerline of the tibial prosthesis 20 is a straight line that bisects the tibial prosthesis 20 into medial and lateral portions, and specifically, the center N of the fourth arc segment 2131 has a second spacing L2 towards the lateral condyle articular surface relative to the central sagittal plane 31 of the tibial prosthesis 20. Preferably, the second distance L2 is 0mm to 2 mm. The eccentric distance (namely the second distance L2) is formed between the circle center N of the fourth arc segment 2131 and the central sagittal plane 31 of the tibial prosthesis 20, so that the femoral prosthesis 10 can be guided to do internal and external rotation motion around the tibial prosthesis 20, the natural motion of the knee joint can be better recovered, and the postoperative proprioception of a patient can be better achieved.

Further, referring to fig. 11, the maximum distance of the tibial prosthesis 20 in the medial-lateral direction is ML, and the distance from the central position of the post 21 to the medial edge of the tibial prosthesis 20 is H, where H is ML/2. And/or the maximum distance between the tibial prosthesis 20 in the anterior-posterior direction is AP, and the distance between the central position of the upright post 21 and the posterior end of the tibial prosthesis 20 is L, wherein L/AP is 0.2-0.5, and preferably, L/AP is 0.3-0.4. The greater the L/AP ratio, the greater the flexion angle at which the cam 13 in the femoral prosthesis 10 comes into contact with the post 21 in the tibial prosthesis 20 during flexion of the knee prosthesis, the less the knee prosthesis will have less frictional wear. When the value of L/AP is 0.3-0.4, the knee joint prosthesis not only can give consideration to the good stability of the knee joint prosthesis, but also can reduce the friction and the abrasion of the knee joint prosthesis.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. 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, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Claims (10)

1. A knee joint prosthesis, comprising:

a tibial prosthesis comprising a tibial articular surface and a post disposed on the tibial articular surface; and the number of the first and second groups,

the femoral prosthesis comprises a medial condyle joint surface, a lateral condyle joint surface and a cam for connecting the medial condyle joint surface and the lateral condyle joint surface, wherein the cam is used for being matched with the upright post, the section of the cam on the sagittal plane forms a first straight line segment facing a central coronal plane and an oblique line segment facing away from the central coronal plane, the first straight line segment and the oblique line segment form an included angle, a first round angle is arranged between the first straight line segment and the oblique line segment, and one end, away from the first round angle, of the oblique line segment is provided with a second round angle.

2. The knee joint prosthesis of claim 1, wherein an angle between the first straight line segment and the oblique line segment is 0 ° to 90 °.

3. The knee joint prosthesis of claim 1, wherein a cross-section of the cam includes first and second oppositely disposed curves, the first and second curves being symmetrically disposed about the first coronal plane.

4. The knee joint prosthesis of claim 3, wherein the first and/or second curves include a first arc segment, a second arc segment connecting the first arc segment with the lateral condyle articular surface, and a third arc segment connecting the first arc segment with the medial condyle articular surface, the first arc segment tangent to the second arc segment and the third arc segment, respectively.

5. The knee prosthesis of claim 4, wherein the center of the first arc segment has a first spacing relative to a central sagittal plane of the femoral prosthesis in a direction toward the medial condyle articular surface.

6. The knee joint prosthesis of claim 4, wherein the first arc segment has a radius of curvature greater than a radius of curvature of the second arc segment, the radius of curvature of the second arc segment being greater than a radius of curvature of the third arc segment.

7. The knee joint prosthesis of claim 6, wherein the tibial articular surface includes a medial bearing surface and a lateral bearing surface, the post includes a medial surface connected to the medial bearing surface, a lateral surface connected to the lateral bearing surface, and a posterior surface connecting the medial surface and the lateral surface and configured to engage the cam, the medial surface being disposed at an angle to the lateral surface, and the distance between the medial surface and the lateral surface increasing in a direction toward the tibial articular surface.

8. The knee joint prosthesis of claim 7, wherein the posterior side surface includes, in cross-section, a fourth arc segment having a radius of curvature less than a radius of curvature of the first arc segment, a fifth arc segment connecting the fourth arc segment with the lateral side surface, and a sixth arc segment connecting the fourth arc segment with the medial side surface; the curvature radius of the fifth circular arc section is smaller than that of the second circular arc section; and the curvature radius of the sixth circular arc section is smaller than that of the third circular arc section.

9. The knee joint prosthesis of claim 7, wherein the posterior side includes a fourth arc segment, a fifth arc segment connecting the fourth arc segment with the lateral side, and a sixth arc segment connecting the fourth arc segment with the medial side, a center of the fourth arc segment having a second spacing toward a direction closer to the lateral bearing surface relative to a central sagittal plane of the tibial prosthesis.

10. The knee joint prosthesis according to claim 1, wherein the maximum distance of the tibial prosthesis in the anteroposterior direction is AP, and the distance from the central position of the pillar to the posterior end of the tibial prosthesis is L, wherein L/AP is 0.2 to 0.5; and/or the maximum distance of the tibial prosthesis in the medial-lateral direction is ML, and the distance from the central position of the upright post to the medial edge of the tibial prosthesis is H, wherein H is ML/2.

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