Medial stable orthopaedic knee prosthesis

Abstract

The orthopaedic knee prosthesis (100) includes a tibial insert (104) and a femoral component (102) configured to articulate on the tibial insert. The tibial insert includes a lateral articular surface (122) and a medial articular surface (124) that is asymmetrically shaped relative to the lateral articular surface. The medial articular surface is shaped to reduce anterior translation of the medial condyle of the femoral component, and the lateral articular surface is shaped to allow the lateral condyle of the femoral component to pivot relative to the medial articular surface along an arcuate articular path (806). Furthermore, one or both condyles (112, 114) of the femoral component may include a femoral articular surface (110) having a curved femoral surface portion defined by a continuously decreasing radius of curvature.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application No. 63 / 050,744, filed July 10, 2020, entitled "ORTHOPAEDIC KNEE PROSTHESIS SYSTEM AND METHODS FOR USING SAME", which is hereby incorporated by reference in its entirety.

[0002] (Field of the Invention) The present disclosure relates to an orthopaedic knee prosthesis system, and more particularly, to orthopaedic knee prostheses, instruments, and methods for total knee arthroplasty.

Background Art

[0003] Arthroplasty is a well - known surgical procedure in which a diseased and / or damaged native joint is replaced with an artificial joint. Conventional knee prostheses include a tibial tray, a femoral component, and a polymeric insert or bearing positioned between the tibial tray and the femoral component. Depending on the severity of the damage to the patient's joint, various degrees of mobility orthopaedic prostheses can be used. For example, a knee prosthesis may include a "fixed" tibial insert in some cases where it is desirable to limit the movement of the knee prosthesis, such as when there is significant soft tissue damage or loss. Alternatively, a knee prosthesis may include a "mobile" tibial insert when a greater degree of freedom of movement is desired. In addition, a knee prosthesis can be a total knee prosthesis designed to replace both femoral condyles of the patient's femur at the femorotibial joint interface, or a unicompartmental (monocondylar) knee prosthesis designed to replace a single femoral condyle of the patient's femur at the femur - tibia joint interface.

[0004] The type of orthopedic knee prosthesis used to replace a patient's natural knee joint can also depend on whether the patient's posterior cruciate ligament is retained or sacrificed (i.e., removed) during surgery. For example, if the patient's posterior cruciate ligament is damaged, diseased, and / or removed in some other way during surgery, a posterior stabilized knee prosthesis can be used to provide additional support and / or control in the posterior flexion range. Alternatively, if the posterior cruciate ligament is intact, a cruciate-retaining knee prosthesis may be used.

[0005] Typical orthopedic knee prostheses are generally designed to reproduce the natural movement of a patient's joint. As the knee flexes and extends, the femoral and tibial components undergo articular motion and experience a combination of relative anterior-posterior motion and relative internal-external rotation. However, the soft tissues around the patient also affect the kinematics and stability of the orthopedic knee prosthesis throughout the range of motion of the joint. That is, the forces exerted on the orthopedic components by the patient's soft tissues can cause unwanted or undesirable movement of the orthopedic knee prosthesis. For example, an orthopedic knee prosthesis can exhibit unnatural (anomalous) anterior joint translation as the femoral component is moved through the flexion range. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0006] According to one aspect, the tibial insert includes a lateral joint surface and a medial joint surface. The lateral joint surface is configured to articulate with the lateral condyle of the femoral component and includes an arcuate joint path that extends in the anteroposterior direction. The arcuate joint path is defined by a plurality of points on the lateral joint surface, and when the tibial insert is viewed in the medial-lateral cross-section at each point, each point defines the most distal point of the lateral joint surface in the corresponding medial-lateral cross-section. The lateral joint surface has a cross-sectional concave curvature that is orthogonal to the arcuate joint path, and the cross-sectional concave curvature is uniform at each of the plurality of points. The medial joint surface is configured to articulate with the medial condyle of the femoral component. The medial joint surface is shaped asymmetrically with respect to the lateral joint surface and has a non-uniform coronal concave curvature in the anteroposterior direction.

[0007] In one embodiment, the medial joint surface includes a medial dome point that defines the most distal point of the medial joint surface. The coronal concave curvature of the medial joint surface is non-uniform in front of the medial dome point and uniform behind the medial dome point.

[0008] In one embodiment, the arcuate joint path has a curvature that includes a quasi-planar portion, a forwardly curved portion located in front of the planar portion, and a plurality of rearwardly curved portions located behind the planar portion when viewed in cross-section. The quasi-planar portion defines a lateral dome region that defines the most distal region of the lateral joint surface. In one embodiment, each of the rearwardly curved portions is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly.

[0009] In one embodiment, the plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, and the radius of curvature of the first rearwardly curved portion is greater than the radius of curvature of the second rearwardly curved portion. In one embodiment, the forwardly curved portion is defined by corresponding radii of curvature that are (i) smaller than the radius of curvature of the first rearwardly curved portion and (ii) greater than the radius of curvature of the second rearwardly curved portion. In one embodiment, the forwardly curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first rearwardly curved portion extends over approximately 3.4 degrees, and the second rearwardly curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees.

[0010] In one embodiment, the inner joint surface includes a sagittal concave curvature defined by a plurality of curved portions and an inner trochlear point that defines the most distal point of the inner joint surface when viewed in the sagittal plane, and the inner trochlear point is located on the sagittal concave curvature. In one embodiment, the plurality of curved portions includes a first curved portion that extends rearward from and adjacent to the inner trochlear point and a second curved portion that extends forward from and adjacent to the inner trochlear point, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. In one embodiment, the first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over approximately 5.2 degrees.

[0011] In one embodiment, the plurality of curved portions includes a third curved portion that extends forward from and adjacent to the second curved portion, a fourth curved portion that extends forward from and adjacent to the third curved portion, and a fifth curved portion that extends forward from and adjacent to the fourth curved portion. The radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of curvature of the fifth curved portion. In one embodiment, the third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth curved portion extends over an arc length in the range of 0.2 degrees to 6.3 degrees.

[0012] In one embodiment, the coronal concave curvature of the inner joint surface is defined by a plurality of coronal curvatures including a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the medial condyle point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first, second, and third coronal curvatures is different from each other. In one embodiment, the first coronal curvature is defined by a coronal curved portion that extends over an arc length in the range of 18.6 degrees to 26.8 degrees inward from the medial condyle point and extends outward from the medial condyle point by about 25.0 degrees. In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. In one embodiment, the radius of curvature of the first coronal curved portion of the second coronal curvature is smaller than the radius of curvature of the second coronal curved portion of the second coronal curvature. In one embodiment, the first coronal curvature of the second coronal curved portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curved portion of the second coronal curvature extends over an arc length in the range of 20.1 degrees to 28.5 degrees.

[0013] In one embodiment, the third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. In one embodiment, the planar portion of the third coronal curvature forms an angle of about 6 degrees with respect to the bottom surface of the tibial insert. In one embodiment, the first coronal curved portion of the third coronal curvature extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curvature extends over an arc length in the range of 16.4 degrees to 24.7 degrees.

[0014] In one embodiment, the tibial insert further includes a front wall and a rear wall opposite the front side, and the distance between the front wall and the rear wall defines the anteroposterior length of the tibial insert. The medial articular surface includes a medial dome point that defines the most distal point of the medial articular surface, and the medial dome point is located at a position about 63.3% of the anteroposterior length from the front end.

[0015] In one embodiment, the medial articular surface includes a medial dome point that defines the most distal point of the medial articular surface, and the arcuate articular path of the lateral articular surface is defined by a radius of curvature having an origin on the medial dome point when viewed in the horizontal plane.

[0016] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0017] According to another aspect, the tibial insert includes a lateral articular surface and a medial articular surface. The lateral articular surface is configured to articulate with the lateral condyle of the femoral component and includes an arcuate articular path extending in the anteroposterior direction. The arcuate articular path has a curvature including a quasi-planar portion when viewed in cross-section, and the quasi-planar portion defines the most distal region of the lateral articular surface. The medial articular surface is configured to articulate with the medial condyle of the femoral component. The medial articular surface is shaped asymmetrically with respect to the lateral articular surface and includes a medial dome point that defines the most distal point of the medial condyle surface. The medial dome point is located on the medial condyle surface between (i) a first virtual medial-lateral bisector of the tibial insert including the most anterior end of the planar portion of the sagittal curvature of the lateral articular surface and a second virtual medial-lateral bisector of the tibial insert including the most posterior end of the planar portion of the sagittal curvature of the lateral articular surface, and (ii) behind the anteroposterior midpoint of the planar portion of the sagittal curvature of the lateral articular surface.

[0018] In one embodiment, the tibial insert further includes a front wall and a rear wall opposite the front side, and the distance between the front wall and the rear wall defines the anteroposterior length of the tibial insert. The medial dovetail point is located at a position about 63.3% of the anteroposterior length from the front end.

[0019] In one embodiment, the medial articular surface has a coronal concave curvature that is non-uniform in front of the medial dovetail point and uniform behind the medial dovetail point.

[0020] In one embodiment, the curvature of the arcuate joint path further includes a front curved portion located in front of the quasi-planar portion and a plurality of rear curved portions located behind the quasi-planar portion when viewed in cross-section. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rear curved portions decrease rearward. In one embodiment, the plurality of rear curved portions includes a first rear curved portion adjacent to and extending from the rearmost end of the planar portion and a second rear curved portion adjacent to the first rear curved portion, and the radius of curvature of the first rear curved portion is larger than the radius of curvature of the second rear curved portion. In one embodiment, the front curved portion is defined by a corresponding radius of curvature that is (i) smaller than the radius of curvature of the first rear curved portion and (ii) larger than the radius of curvature of the second rear curved portion. In one embodiment, the front curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first rear curved portion extends over about 3.4 degrees, and the second rear curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees.

[0021] In one embodiment, the medial articular surface includes a sagittal concave curvature defined by a plurality of curved portions when viewed in the sagittal plane, and the medial dovetail point is located on the sagittal concave curvature. In one embodiment, the plurality of curved portions includes a first curved portion adjacent to and extending rearward from the medial dovetail point and a second curved portion adjacent to and extending forward from the medial dovetail point, and the radius of curvature of the first curved portion is larger than the radius of curvature of the second curved portion. In one embodiment, the first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over about 5.2 degrees.

[0022] In one embodiment, the plurality of curved portions includes a third curved portion that extends forward from and is adjacent to the second curved portion, a fourth curved portion that extends forward from and is adjacent to the third curved portion, and a fifth curved portion that extends forward from and is adjacent to the fourth curved portion. The radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of curvature of the fifth curved portion. In one embodiment, the third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth curved portion extends over an arc length in the range of 0.2 degrees to 6.3 degrees.

[0023] In one embodiment, the inner joint surface has a coronal curvature defined by a plurality of coronal curves, including a first coronal curve that intersects the sagittal concave curve of the inner joint surface at the inner trochlear point, a second coronal curve located in front of the first coronal curve, and a third coronal curve located in front of the second coronal curve. Each of the first, second, and third coronal curves is different from each other. In one embodiment, the first coronal curve is defined by a coronal curved portion that extends inward from the inner trochlear point over an arc length in the range of 18.6 degrees to 26.8 degrees and extends outward from the inner trochlear point by approximately 25.0 degrees.

[0024] In one embodiment, the second coronal curve intersects the sagittal concave curve of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curve of the inner joint surface. The second coronal curve is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. In one embodiment, the radius of curvature of the first coronal curved portion of the second coronal curve is smaller than the radius of curvature of the second coronal curved portion of the second coronal curve. In one embodiment, the first coronal curve of the second coronal curved portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curved portion of the second coronal curve extends over an arc length in the range of 20.1 degrees to 28.5 degrees.

[0025] In one embodiment, the third coronal curvature intersects the sagittal concave curvature of the medial articular surface at the foremost point of a fourth curved portion among a plurality of curved portions that define the sagittal concave curvature of the medial articular surface. The third coronal curvature is defined by a planar portion having a medial end and a lateral end, a first coronal curved portion extending from the medial end of the planar portion, and a second coronal curved portion extending from the lateral end of the planar portion. In one embodiment, the planar portion of the third coronal curvature forms an angle of approximately 6 degrees with the bottom surface of the tibial insert. In one embodiment, the first coronal curved portion of the third coronal curvature extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curvature extends over an arc length in the range of 16.4 degrees to 24.7 degrees.

[0026] In one embodiment, the arcuate joint path is defined by a radius of curvature having an origin on the medial door point when viewed in the horizontal plane.

[0027] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0028] According to another aspect, the tibial insert includes an outer joint surface configured to articulate with the outer condyle of the femoral component and an inner joint surface configured to articulate with the inner condyle of the femoral component. The outer joint surface includes an arcuate joint path extending in the anteroposterior direction, an outer dovetail point defining the most distal point on the outer joint surface located on the arcuate joint path, and an anterior lateral lip. The vertical distance between the outer dovetail point and the uppermost point of the anterior lateral lip defines the lip height of the anterior lateral lip. The inner joint surface is shaped asymmetrically with respect to the outer joint surface and includes an inner dovetail point defining the most distal point on the inner joint surface and an anterior medial lip. The vertical distance between the inner dovetail point and the uppermost point of the inner lateral lip defines the lip height of the anterior medial lip. The lip height of the anterior medial lip is higher than the lip height of the anterior lateral lip, and the ratio of the lip height of the anterior medial lip to the anteroposterior distance between the anterior side wall and the posterior side wall of the inner joint surface ranges from 18.9% to 20.9%.

[0029] In one embodiment, the inner joint surface has a non-uniform concavo-convex curvature in front of the inner dovetail point and a uniform concavo-convex curvature behind the inner dovetail point.

[0030] In one embodiment, the arcuate joint path has a curvature including a quasi-planar portion, a front curved portion located in front of the planar portion, and a plurality of rear curved portions located behind the planar portion when viewed in cross section. The outer dovetail point is located in the quasi-planar portion.

[0031] In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rear curved portions decrease rearward.

[0032] In one embodiment, the plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, and the radius of curvature of the first rearwardly curved portion is greater than the radius of curvature of the second rearwardly curved portion. In one embodiment, the forwardly curved portion is defined by corresponding radii of curvature that are (i) less than the radius of curvature of the first rearwardly curved portion and (ii) greater than the radius of curvature of the second rearwardly curved portion. In one embodiment, the forwardly curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first rearwardly curved portion extends over approximately 3.4 degrees, and the second rearwardly curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees.

[0033] In one embodiment, the inner articular surface includes a sagittal concave curvature defined by a plurality of curved portions when viewed in the sagittal plane, and the inner doell point is located on the sagittal concave curvature. In one embodiment, the plurality of curved portions includes a first curved portion adjacent to and extending rearwardly from the inner doell point and a second curved portion adjacent to and extending forwardly from the inner doell point, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. In one embodiment, the first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over approximately 5.2 degrees.

[0034] In one embodiment, the plurality of curved portions includes a third curved portion adjacent to and extending forwardly from the second curved portion, a fourth curved portion adjacent to and extending forwardly from the third curved portion, and a fifth curved portion adjacent to and extending forwardly from the fourth curved portion, and the radius of curvature of the third curved portion is less than the radius of curvature of the second curved portion, less than the radius of curvature of the fourth curved portion, and less than the radius of the fifth curvature radius. In one embodiment, the third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length in the range of 0.2 degrees to 6.3 degrees.

[0035] In one embodiment, the inner joint surface has a coronal curvature defined by a plurality of coronal curvatures including a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the medial femoral point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first, second, and third coronal curvatures is different from each other. In one embodiment, the first coronal curvature is defined by a coronal curvature portion that extends over an arc length in the range of 18.6 degrees to 26.8 degrees inwardly from the medial femoral point and extends outwardly from the medial femoral point by about 25.0 degrees.

[0036] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curvature portion extending from the inner end of the planar portion, and a second coronal curvature portion extending from the outer end of the planar portion. In one embodiment, the radius of curvature of the first coronal curvature portion of the second coronal curvature is smaller than the radius of curvature of the second coronal curvature portion of the second coronal curvature. In one embodiment, the first coronal curvature of the second coronal curvature portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length in the range of 20.1 degrees to 28.5 degrees.

[0037] In one embodiment, the third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curvature portion extending from the inner end of the planar portion, and a second coronal curvature portion extending from the outer end of the planar portion. In one embodiment, the planar portion of the third coronal curvature forms an angle of about 6 degrees with respect to the bottom surface of the tibial insert. In one embodiment, the first coronal curvature portion of the third coronal curvature extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curvature portion of the third coronal curvature extends over an arc length in the range of 16.4 degrees to 24.7 degrees.

[0038] In one embodiment, the tibial insert further includes a front side and a rear side opposite the front side. The distance between the front side and the rear side defines the anteroposterior length of the tibial insert. The medial dome point is located at a position of about 63.3% of the anteroposterior length from the front end. In one embodiment, the arcuate joint path of the lateral articular surface is defined by a radius of curvature having an origin on the medial dome point when viewed in the horizontal plane.

[0039] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0040] According to yet another aspect, an orthopedic knee prosthesis includes a femoral component having a lateral condyle and a medial condyle, and a tibial insert having a lateral articular surface configured to articulate with the lateral condyle of the femoral component and a medial articular surface configured to articulate with the medial condyle of the femoral component. The medial condyle includes a femoral articular surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion defined by a continuously decreasing radius of curvature. The medial articular surface is shaped asymmetrically with respect to the lateral articular surface and includes a medial dome point that defines the most distal point on the medial articular surface. The medial condyle contacts the medial dome point at a first contact point on the first curved femoral surface portion at a first flexion angle and at a second contact point on the first curved femoral surface portion at a second flexion angle, the second contact point being posterior to the first contact point and the second flexion angle being greater than the first flexion angle. The medial articular surface includes a sagittal concave curvature having a first sagittal conformity with the medial condyle at a position anterior to the dome point at the first flexion angle and a second sagittal conformity with the medial condyle at a position anterior to the dome point at the second flexion angle, the second sagittal conformity being greater than the first sagittal conformity and reducing the anterior translation of the medial condyle at the second flexion angle.

[0041] In one embodiment, the medial condyle of the femoral component includes a sagittal convex curvature, and the sagittal conformity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater at a first flexion angle of the femoral condyle than at extension. In one embodiment, the first flexion angle is about 30 degrees.

[0042] In one embodiment, the medial articular surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle at that flexion angle is greater at the medial trochlear point of the medial articular surface than at a position on the medial articular surface in front of the medial trochlear point. In one embodiment, the medial articular surface is non-uniform in front of the medial trochlear point and uniform behind the medial trochlear point.

[0043] In one embodiment, the medial condyle and the medial articular surface are more conformable to each other than the lateral condyle and the lateral articular surface.

[0044] In one embodiment, the medial articular surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a later flexion angle.

[0045] In one embodiment, the lateral articular surface includes an arcuate articular path having a curvature that, in cross-section, includes a planar portion, a forwardly curved portion located in front of the planar portion, and a plurality of rearwardly curved portions located behind the planar portion. The planar portion defines the most distal region of the lateral articular surface. In one embodiment, each rearwardly curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly.

[0046] In one embodiment, the sagittal concave curvature of the inner joint surface includes a plurality of curved portions when viewed in the sagittal plane, and the inner dovetail point is located on the sagittal concave curvature. The plurality of curved portions include a first curved portion adjacent to and extending rearward from the inner dovetail point, a second curved portion adjacent to and extending forward from the inner dovetail point, a third curved portion adjacent to the second curved portion and extending forward from it, a fourth curved portion adjacent to the third curved portion and extending forward from it, and a fifth curved portion adjacent to the fourth curved portion and extending forward from it. The radius of curvature of the first curved portion is larger than the radius of curvature of the second curved portion, and the radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth curvature radius.

[0047] In one embodiment, the inner joint surface includes a coronal concave curvature defined by a plurality of coronal curvatures, including a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the inner dovetail point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first, second, and third coronal curvatures is different from each other. In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion, and the radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion. In one embodiment, the third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion.

[0048] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to mate with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0049] In one embodiment, the most distal point of the femoral joint surface when the femoral component is in the extended state defines 0 degrees of flexion, and the first curved femoral surface portion extends from a first flexion degree of about 5 degrees to a second flexion degree of about 65 degrees. In one embodiment, the first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion. Each line has a length defined by the following polynomial. r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 )) where r θ is the length of the line defining the point on the second curved femoral surface portion at θ degrees of flexion, a is a coefficient value between 20 and 50, b is a coefficient value in the range selected from the group consisting of -0.30 < b < 0.00, 0.00 < b < 0.30, and b = 0, when b is in the range of -0.30 < b < 0.00, (i) c is a coefficient value between 0.00 and 0.012, (ii) d is a coefficient value between -0.00015 and 0.00, when b is in the range of 0 < b < 0.30, (i) c is a coefficient value between -0.010 and 0.00, (ii) d is a coefficient value between -0.00015 and 0.00, when b is equal to 0, (i) c is a coefficient value in the range selected from the group consisting of -0.0020 < c < 0.00 and 0.00 < c < 0.0025, (ii) d is a coefficient value between -0.00015 and 0.00.

[0050] In one embodiment, the plurality of curved femoral surface portions includes a second curved femoral surface portion adjacent to the rear of the first curved femoral portion, and the second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature at the rearmost of the first curved femoral surface portion. In one embodiment, the second curved femoral surface portion extends from a first flexion angle of about 65 degrees to a second flexion angle of about 90 degrees.

[0051] According to another aspect, an orthopedic knee prosthesis includes a femoral component having a lateral condyle and a medial condyle, and a tibial insert having a lateral articular surface configured to articulate with the lateral condyle of the femoral component and a medial articular surface configured to articulate with the medial condyle of the femoral component. The medial condyle includes a femoral articular surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion and a second curved femoral surface portion adjacent to the rear of the first curved femoral surface portion, the first curved femoral surface portion being defined by a continuously decreasing radius of curvature and the second curved femoral surface portion being defined by a constant radius of curvature greater than the radius of curvature at the rearmost of the first curved femoral surface portion. The medial articular surface is shaped asymmetrically relative to the lateral articular surface and includes a medial dome point that defines the most distal point on the medial articular surface. The medial condyle contacts the medial dome point at a first contact point on the first curved femoral surface portion at a first flexion angle, the first contact point being defined by the radius of curvature at the rearmost of the first curved femoral surface portion, and (ii) contacts the medial dome point at a second contact point on the second curved femoral surface portion at a second flexion angle greater than the first flexion angle, the second contact point being defined by the constant radius of curvature of the second curved femoral surface portion. The vertical distance between the medial dome point at the second flexion angle and the origin of the constant radius of curvature of the second curved femoral surface portion is greater than the vertical distance between the medial dome point at the first flexion angle and the origin of the radius of curvature at the rearmost of the first curved femoral surface portion.

[0052] In one embodiment, the medial condyle of the femoral component includes a sagittal convex curvature, the medial articular surface includes a sagittal concave curvature, and the sagittal conformity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater at a first flexion angle of the femoral condyle than at extension. In one embodiment, the first flexion angle is about 30 degrees.

[0053] In one embodiment, the medial articular surface includes a sagittal concave curvature. At the medial trochlear point, the sagittal concave curvature has a first sagittal conformity with the medial condyle at the first flexion angle of the femoral component. At a position on the medial articular surface in front of the medial trochlear point, the sagittal concave curvature has a second sagittal conformity with the medial condyle at the first flexion angle, and the second sagittal conformity is greater than the first sagittal conformity.

[0054] In one embodiment, the medial articular surface includes a coronal concave curvature. At the medial trochlear point, the coronal concave curvature has a first coronal conformity with the medial condyle at the first flexion angle. At a position on the medial articular surface in front of the medial trochlear point, the coronal concave curvature has a second coronal conformity with the medial condyle at the first flexion angle, and the second coronal conformity is greater than the first coronal conformity. In one embodiment, the medial articular surface is non-uniform in front of the medial trochlear point and uniform behind the medial trochlear point.

[0055] In one embodiment, the medial condyle and the medial articular surface are more conformable to each other than the lateral condyle and the lateral articular surface.

[0056] In one embodiment, the medial articular surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a later flexion angle.

[0057] In one embodiment, the outer joint surface, when viewed in cross-section, includes an arcuate joint path having a curvature that includes a quasi-planar portion, a forwardly curved portion located forward of the quasi-planar portion, and a plurality of rearwardly curved portions located rearward of the planar portion. The planar portion defines the most distal region of the outer joint surface. In one embodiment, each rearwardly curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly.

[0058] In one embodiment, the sagittal concave curvature of the inner joint surface includes a plurality of curved portions when viewed in the sagittal plane, and the inner doell point is located on the sagittal concave curvature. The plurality of curved portions includes a first curved portion that extends rearward from adjacent to the inner doell point, a second curved portion that extends forward from adjacent to the inner doell point, a third curved portion that extends forward from adjacent to the second curved portion, a fourth curved portion that extends forward from adjacent to the third curved portion, and a fifth curved portion that extends forward from adjacent to the fourth curved portion. The radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion, and the radius of curvature of the third curved portion is less than the radius of curvature of the second curved portion, less than the radius of curvature of the fourth curved portion, and less than the radius of the fifth radius of curvature.

[0059] In one embodiment, the inner joint surface includes a coronal concave curvature defined by a plurality of coronal curvatures, including a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the inner doell point, a second coronal curvature located forward of the first coronal curvature, and a third coronal curvature located forward of the second coronal curvature, and each of the first, second, and third coronal curvatures is different from the others.

[0060] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion of the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion, and the radius of curvature of the first coronal curved portion is less than the radius of curvature of the second coronal curved portion.

[0061] In one embodiment, the third coronal curve intersects the sagittal concave curve of the medial articular surface at the foremost point of a fourth curved portion among a plurality of curved portions that define the sagittal concave curve of the medial articular surface, and the third coronal curve is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion.

[0062] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert, and the first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0063] In one embodiment, the most distal point of the femoral articular surface when the femoral component is in the extended state defines 0 degrees of flexion, and the first curved femoral surface portion extends from a first flexion angle of about 5 degrees to a second flexion angle of about 65 degrees. In one embodiment, the first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion. Each line has a length defined by the following polynomial. r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 ))、where r θis the length of a line defining a point on the second curved femoral surface portion at a flexion of θ degrees, a is a coefficient value of 20 to 50, b is a coefficient value in the range selected from the group consisting of -0.30 < b < 0.00, 0.00 < b < 0.30, and b = 0. When b is in the range of -0.30 < b < 0.00, (i) c is a coefficient value of 0.00 to 0.012, and (ii) d is a coefficient value of -0.00015 to 0.00. When b is in the range of 0 < b < 0.30, (i) c is a coefficient value of -0.010 to 0.00, and (ii) d is a coefficient value of -0.00015 to 0.00. When b is equal to 0, (i) c is a coefficient value in the range selected from the group consisting of -0.0020 < c < 0.00 and 0.00 < c < 0.0025, and (ii) d is a coefficient value of -0.00015 to 0.00.

[0064] In one embodiment, the plurality of curved femoral surface portions includes a second curved femoral surface portion adjacent to the rear of the first curved femoral portion, and the second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature of the rearmost portion of the first curved femoral surface portion. In one embodiment, the second curved femoral surface portion extends from a first flexion of about 65 degrees to a second flexion of about 90.

[0065] According to another aspect, an orthopedic knee prosthesis includes a femur component having a lateral condyle and a medial condyle, and a tibial insert having a lateral articular surface configured to articulate with the lateral condyle of the femur component and a medial articular surface configured to articulate with the medial condyle of the femur component. The medial condyle includes a femoral articular surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion defined by a continuously decreasing radius of curvature. The lateral articular surface includes an arcuate articular path extending in the anteroposterior direction, and the arcuate articular path has a curvature including a planar portion when viewed in cross section, and the planar portion defines the most distal region of the lateral articular surface. The medial articular surface is shaped asymmetrically with respect to the lateral articular surface and includes a medial dovetail point that defines the most distal point of the medial condyle surface, and the medial dovetail point is on the medial condyle surface, (i) between a first virtual medial-lateral bisector of the tibial insert including the foremost end of the planar portion of the sagittal curvature of the lateral articular surface and a second virtual medial-lateral bisector of the tibial insert including the rearmost end of the planar portion of the sagittal curvature of the lateral articular surface, and (ii) posterior to the anteroposterior midpoint of the planar portion of the sagittal curvature of the lateral articular surface.

[0066] In one embodiment, the medial condyle of the femur component includes a sagittal convex curvature, the medial articular surface includes a sagittal concave curvature, and the sagittal conformity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater at a first flexion angle of the femoral condyle than at extension. In one embodiment, the first flexion angle is about 30 degrees.

[0067] In one embodiment, the medial articular surface includes a sagittal concave curvature, and at the medial dovetail point, the sagittal concave curvature has a first sagittal conformity with the medial condyle at a first flexion angle of the femur component, and at a position on the medial articular surface anterior to the medial dovetail point, the sagittal concave curvature has a second sagittal conformity with the medial condyle at the first flexion angle, and the second sagittal conformity is greater than the first sagittal conformity.

[0068] In one embodiment, the inner joint surface includes a coronal concave curvature. At the medial trochlear point, the coronal concave curvature has a first flexion degree and a first coronal conformity with the medial condyle. At a position on the inner joint surface in front of the medial trochlear point, the coronal concave curvature has a first flexion degree and a second coronal conformity with the medial condyle, and the second coronal conformity is greater than the first coronal conformity. In one embodiment, the inner joint surface is non-uniform in front of the medial trochlear point and uniform behind the medial trochlear point.

[0069] In one embodiment, the inner joint surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a later flexion degree.

[0070] In one embodiment, the arcuate joint path of the outer joint surface has a curvature including a quasi-planar portion, a front curved portion located in front of the planar portion, and a plurality of rear curved portions located behind the planar portion when viewed in cross-section. The quasi-planar portion defines the most distal region of the outer joint surface. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rear curved portions decrease rearward.

[0071] In one embodiment, the sagittal concave curvature of the inner joint surface includes a plurality of curved portions when viewed in the sagittal plane, and the medial trochlear point is located on the sagittal concave curvature. The plurality of curved portions include a first curved portion adjacent to and extending rearward from the medial trochlear point, a second curved portion adjacent to and extending forward from the medial trochlear point, a third curved portion adjacent to and extending forward from the second curved portion, a fourth curved portion adjacent to and extending forward from the third curved portion, and a fifth curved portion adjacent to and extending forward from the fourth curved portion. The radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion, and the radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of curvature of the fifth curved portion.

[0072] In one embodiment, the medial articular surface includes a coronal concave curvature defined by a plurality of coronal curvatures, including a first coronal curvature that intersects the sagittal concave curvature of the medial articular surface at the medial door point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first, second, and third coronal curvatures is different from each other.

[0073] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at the last point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the medial articular surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion, and the radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion.

[0074] In one embodiment, the third coronal curvature intersects the sagittal concave curvature of the medial articular surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the medial articular surface, and the third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion.

[0075] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert, and the first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base.

[0076] In one embodiment, the most distal point of the femoral articular surface when the femoral component is in the extended state defines 0 degrees of flexion. The first curved femoral surface portion extends from approximately the first flexion degree of about 5 degrees to the second flexion degree of about 65 degrees. In one embodiment, the first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion. Each line has a length defined by the following polynomial. r θ=(a + (b * θ) + (c * θ 2 )) + (d * θ 3 ))), where r θ is the length of the line defining a point on the second curved femoral surface portion at a flexion of θ degrees, a is a coefficient value between 20 and 50, b is a coefficient value in the range selected from the group consisting of -0.30 < b < 0.00, 0.00 < b < 0.30, and b = 0. When b is in the range of -0.30 < b < 0.00, (i) c is a coefficient value between 0.00 and 0.012, (ii) d is a coefficient value between -0.00015 and 0.00. When b is in the range of 0 < b < 0.30, (i) c is a coefficient value between -0.010 and 0.00, (ii) d is a coefficient value between -0.00015 and 0.00. When b is equal to 0, (i) c is a coefficient value in the range selected from the group consisting of -0.0020 < c < 0.00 and 0.00 < c < 0.0025, (ii) d is a coefficient value between -0.00015 and 0.00.

[0077] In one embodiment, the plurality of curved femoral surface portions include a second curved femoral surface portion adjacent to the rear of the first curved femoral portion, and the second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature at the rearmost of the first curved femoral surface portion. In one embodiment, the second curved femoral surface portion extends from a first flexion angle of about 65 degrees to a second flexion angle of about 90 degrees.

Brief Description of the Drawings

[0078] For a detailed description, specifically, refer to the following drawings.

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BEST MODE FOR CARRYING OUT THE INVENTION

[0079] While the concepts of the present disclosure are capable of various modifications and alternative forms, specific exemplary embodiments thereof are shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the present disclosure is not intended to be limited to the particular forms disclosed, but on the contrary, the present invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended "claims".

[0080] Terms such as anterior, posterior, medial, lateral, superior, inferior, etc., which represent anatomical references, may be used throughout this specification with respect to the orthopedic implants and / or surgical instruments described herein, as well as with respect to the patient's living anatomical structures. Such terms have meanings that are well understood in both the study of anatomy and the field of orthopedic surgery. The use of such anatomical reference terms in the description and "claims" provided is intended to be consistent with their well-understood meanings unless otherwise specified. Further, the term "about" may be used herein with respect to specific dimensions defined within manufacturing tolerances. That is, the provided dimensions and / or numerical values may actually deviate by the tolerances inherent in the machine or manufacturing process.

[0081] References to "one embodiment", "an embodiment", "exemplary embodiments", etc. in this specification indicate that the embodiment being described may include a particular element, structure, or feature, but not all embodiments necessarily include that particular element, structure, or feature. Further, such phrases do not necessarily refer to the same embodiment. Further, when a particular element, structure, or feature is described in relation to an embodiment, it is considered within the knowledge of those skilled in the art to implement such element, structure, or feature in relation to other embodiments, whether or not explicitly stated. Further, it should be understood that items included in a list in the form of "at least one of A, B, and C" may mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Similarly, items listed in the form of "at least one of A, B, or C" may mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

[0082] In the drawings, some structural or method elements may be shown in a particular arrangement and / or order. However, it should be recognized that such particular arrangement and / or order may not be necessary. Rather, in some embodiments, such elements may be arranged in a different form and / or order than shown in the illustrative drawings. Additionally, if a structural or method element is included in a particular figure, it does not imply that such element is necessary in all embodiments, and in some embodiments it may not be included or may be combined with other elements.

[0083] Referring now to FIGS. 1-3, in an exemplary embodiment, an orthopedic knee prosthesis 100 includes a femoral component 102 and a tibial insert 104. Additionally, the orthopedic knee prosthesis 100 may include a tibial tray (not shown) to which the tibial insert 104 is coupled during use. The femoral component 102 (and the tibial tray) is illustratively formed from a metallic material such as cobalt chrome or titanium, although in other embodiments, it may be formed from other materials such as ceramic materials, polymer materials, or biomaterials. The tibial insert 104 is illustratively formed from a polymer material such as ultra-high molecular weight polyethylene (UHMWPE), although in other embodiments, it may be formed from other materials such as ceramic materials, metallic materials, or biomaterials.

[0084] The femoral component 102 is configured to be coupled to a surgically prepared surface at a distal end of a patient's femur (not shown), and the tibial insert 104 is configured to be coupled to a surgically prepared surface at a proximal end of a patient's tibia (not shown), for example via a tibial tray (not shown). Alternatively, in other embodiments, the tibial insert 104 may be configured to be directly attached to a surgically prepared surface at the proximal end of the patient's tibia without using a tibial tray. For example, the tibial insert 104 and a polymeric "tray" may be combined into a single polymeric component.

[0085] During use, the femoral component 102 is configured to articulate with the tibial insert 104. To do so, the femoral component includes an articulating outer surface 110 having a lateral condyle 112 and a medial condyle 114. Similarly, the tibial insert 104 includes an articulating surface 120 having a lateral articulating surface 122 and a medial articulating surface 124. Accordingly, the lateral condyle 112 is configured to articulate with the lateral articulating surface 122, and the medial condyle 114 is configured to articulate with the medial articulating surface 124 of the tibial insert as shown in FIGS. 28-31.

[0086] As will be described in more detail below, each of the femur component 102 and the tibial insert 104 includes articular curvature and related features that facilitate or promote the pivotal movement of the lateral condyle 112 at the lateral articular surface 122 while restricting or reducing the forward translation of the medial condyle 114 at the medial articular surface 124 during flexion. For example, one or both of the condyles 112, 114 include a sagittal condyle surface having a curved surface portion defined by a continuously decreasing radius of curvature. Further, the medial articular surface 124 has a concave sagittal curvature that is generally more conforming to the convex sagittal curvature of the medial condyle 114 at an intermediate flexion degree (e.g., 30 degrees) than in extension. The lateral and medial articular surfaces 122, 124 of the tibial insert 104 are also asymmetrically shaped to provide an asymmetric pivot of the femur component 102 on the tibial insert 104. Additionally, the lateral articular surface 122 and the lateral condyle 112 may be less conformable to each other than the medial articular surface 124 and the medial condyle 114. Further, as will be described below, the coronal curvature of the lateral articular surface 122 is uniform in the anteroposterior direction, while the coronal curvature of the medial articular surface 124 is non-uniform in the anteroposterior direction (e.g., the coronal curvature of the medial articular surface 124 is defined by a plurality of different coronal curvatures). Additionally, the medial articular surface 124 may be more conformable to the medial condyle 114 in extension than in flexion, and more conformable anterior to the doell point of the medial condyle 114 than at the doell point of the medial condyle 114, by the sagittal shape of the medial articular surface 124 (see the description of FIGS. 18-27 below). It should be understood that the stability of the orthopedic knee prosthesis 100 is improved, the pivotal movement of the lateral femoral condyle 112 is facilitated, and the forward translation of the femur medially is reduced or restricted by the sagittal curvature of the femoral condyles 112, 114, the overall sagittal conformity between the medial condyle 114 and the medial articular surface 124, the asymmetry of the lateral and medial articular surfaces 122, 124, and the increased conformity in extension and anterior to the doell point of the medial condyle 114.

[0087] As described above, the femur component 102 is configured to be coupled to a surgically prepared surface of the distal end of a patient's femur (not shown) and can be secured to the patient's femur by use of bone cement or other attachment means. The femur component 102 includes a lateral condyle 112 and a medial condyle 114, which are spaced apart to define an intercondylar opening 116 therebetween. In use, the condyles 112, 114 are configured to articulate on corresponding lateral and medial articular surfaces 122, 124 of the tibial insert 104 so as to replace the native condyles of the patient's femur.

[0088] Referring now to FIG. 4, one or both of the condyles 112, 114 of the femur component 102 include a condylar surface 400 that is convexly curved in the sagittal plane. Exemplarily, the condylar surface 400 is formed from a number of curved surface portions 402, 404, 406, 408, 410, and 412, each of which is in contact with an adjacent curved surface portion. Each curved surface portion 402, 404, 406, 408, 410, and 412 contacts the tibial bearing insert through a different range of flexion degrees. For example, the curved surface portions 402, 404 of the condylar surface 400 contact the tibial insert 104 during initial flexion. The curved surface portions 406, 408 of the condylar surface 400 contact the tibial insert 104 during mid-flexion. Also, the curved surface portions 410, 412 of the condylar surface 400 contact the tibial insert 104 during terminal flexion.

[0089] Each of the curved surface portions 402, 406, 408, 410, and 412 is defined by a respective constant radius of curvature R1, R3, R4, R5, and R6. However, as will be described in more detail below, the curved surface portion 404 is not defined by a constant radius of curvature but rather by a plurality of lines. In particular, the curved surface portion 3604 is designed such that the condylar surface 400 gradually transitions from the radius of curvature R1 of the curved surface portion 402 to the radius of curvature R2 where it contacts the curved surface portion 406. Thus, the curved surface portion 3604 has a continuously decreasing radius of curvature.

[0090] In the exemplary embodiment shown in Table 500 of FIG. 5, the curved surface portion 402 defined by the radius of curvature R1 ranges from a first bend angle of -5 degrees to a second bend angle of 5 degrees. The curved surface portion 404 defined by the radius of curvature R2 ranges from a first bend angle of 5 degrees to a second bend angle of 65 degrees. The curved surface portion 406 defined by the radius of curvature R3 ranges from a first bend angle of 65 degrees to a second bend angle of 90 degrees. The curved surface portion 408 defined by the radius of curvature R4 ranges from a first bend angle of 90 degrees to a second bend angle of 105 degrees. The curved surface portion 410 defined by the radius of curvature R5 ranges from a first bend angle of 105 degrees to a second bend angle of 120 degrees. Also, the curved surface portion 412 defined by the radius of curvature R6 ranges from a first bend angle of 120 degrees to a second bend angle of 163 degrees (or 155 degrees depending on the size). In other embodiments, any of the curved surface portions 402, 406, 408, 410, and 412 may have ranges over different degrees.

[0091] As shown in FIG. 6, Table 600 defines the lengths of each of the radii of curvature R1, R2, R3, R4, R5, and R6 for a group of femoral component sizes 1-10. As shown in Table 600, the specific lengths of each of the radii of curvature R1, R2, R3, R4, R5, R6 for each size 1-10 of the femoral component 102 may vary over the size, but the ratios of R1 / R2, R1 / R3, and R1 / R4 are relatively constant or vary slightly over the femoral component size. For example, the ratio of the radius of curvature R1 to the radius of curvature R2 may vary in the range of about 1.347 to 1.355 so as to maintain a value of about 1.350 over the femoral component sizes 1-10. Similarly, the ratio of the radius of curvature R1 to the radius of curvature R3 may vary in the range of about 1.277 to 1.278 so as to maintain a value of about 1.280 over the femoral component sizes 1-10. Further, the ratio of the radius of curvature R1 to the radius of curvature R4 may be maintained at a value of about 1.305 over the femoral component sizes 1-10.

[0092] It should also be understood that in some embodiments, the femoral component 102's spherical surface 400 is designed such that the radius of curvature R3 is greater than the radius of curvature R2 by an amount in the range of about 0.5 millimeters to about 5 millimeters. As will be described below, in some embodiments, the specific increase amount can be based on the size of the femoral component. Further, based on the above analysis, the spherical surface 400 is designed such that the increase in the radius of curvature from R2 to R3 occurs at a bend angle in the range of about 45 degrees to about 90 degrees. In a particular embodiment, the increase in the radius of curvature from R2 to R3 occurs at a bend of about 65 degrees on the spherical surface 400.

[0093] As described above, the curved surface portion 404 is designed to provide a gradual transition from the radius of curvature R1 to the radius of curvature R2. Therefore, the magnitude of the angle defined by the curved surface portion 404 can be selected based on the desired transition rate. For example, in some embodiments, the spherical surface 400 of the femoral component 102 is designed such that the curved surface portion 404 extends from a first bend angle in the range of about 0.0 to about 30.0 degrees to a second bend angle in the range of about 45.0 to about 90.0 degrees. In a particular embodiment, the curved surface portion 404 extends from a bend angle of about 5.0 degrees to a bend angle of about 65.0 degrees, as described above.

[0094] It should also be understood that a specific increase in the radius of curvature R2 to R3 of the femoral component 102 on the spherical surface 400, and / or the placement of such an increase on the spherical surface 400, may be based on, determined according to, or otherwise affected by the size of the femoral component 102. That is, an increase of 0.5 millimeters in the radius of curvature of the spherical surface 400 from R2 to R3 is a relatively large increase for a small-sized femoral component compared to a larger-sized femoral component. Therefore, the magnitude of the increase in the radius of curvature of the spherical surface 400 of the femoral component 102 from R2 to R3 can vary across the size of the femoral component. However, in some embodiments, the ratio of the radius of curvature R1 to the radii of curvature R2, R3, and R4 is maintained at a substantially constant value across a group of femoral component sizes.

[0095] As described above, the curved surface portion 404 is designed to provide a gradual transition from the radius of curvature R1 to the radius of curvature R2. To do so, the curved surface portion 404 is defined by a plurality of lines 420 starting from a common origin O. Each of the plurality of lines 420 defines a respective contact point on the curved surface portion 404. The position of each of these contact points that collectively define the curved surface portion 404 can be determined based on the length of each line 420 at each degree of flexion according to the following polynomial. r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 ))、(3) where "r θ " is the length (in metric units) of the line 420 that defines the contact point on the curved surface portion 404 at a flexion of "θ" degrees, "a" is a scalar value between 20 and 50, and "b" is a coefficient value selected as follows. -0.30 < b < 0.00, (4) 0.00 < b < 0.30, or b = 0

[0096] When the selected coefficient "b" is in the range of -0.30 < b < 0.00, the coefficients "c" and "d" are selected as follows. 0.00 < c < 0.012, and (5) -0.00015 < d < 0.00.

[0097] Alternatively, when the selected coefficient "b" is in the range of 0.00 < b < 0.30, the coefficients "c" and "d" are selected as follows. -0.010 < c < 0.00, and (6) -0.00015 < d < 0.00.

[0098] Furthermore, when the selected coefficient "b" is equal to 0, the coefficients "c" and "d" are selected as follows. -0.0020 < c < 0.00, or (7) 0.00 < c < 0.0025, and -0.00015 < d < 0.00.

[0099] It should be understood that the scalar value "a" and the ranges of the coefficient values "b", "c", and "d" are a subset of the infinite possible solutions of the polynomial (3). That is, a particular set of the ranges given above is determined from among the infinite possibilities of generating a group of curves (i.e., the curved surface portion 404) that provides a gradual transition from the radius of curvature R1 to the radius of curvature R2 of the femoral surface 400 such that the forward translational movement (e.g., medial forward translational movement) of the femoral component 102 relative to the tibial insert 104 is reduced or delayed. Further, it should be understood that the ranges of each coefficient value "a", "b", "c", and "d" are provided above with respect to embodiments designed using SI units. However, such ranges of coefficient values may be converted for use in embodiments using other unit systems such as the foot-pound unit system.

[0100] The overall shape of the curved surface portion 404 is also affected by the arrangement of the common origin O of the plurality of lines 420. By restricting the distance between the common origin O of the plurality of lines 420 and the origin 422 of the radius of curvature R1 that defines the initially bent curved surface portion 402, the strange forward sliding of the femoral component 102 on the tibial insert 104 can be reduced or delayed. Thus, in one embodiment, the position of the common origin O of the plurality of lines 420 is selected such that the distance between the common origin O and the origin 422 of the radius of curvature R1 is less than about 10 millimeters. It should be understood that the distance between the common origin O and the origin 422 of the radius of curvature R1 and the specific coefficient values may depend on the specific size of the femoral component 102 in some embodiments. Exemplary embodiments of the distance between the common origin O and the origin 422 of the radius of curvature R1 and the specific coefficient values of Equation (3) are shown in Table 700 of FIG. 7.

[0101] In other embodiments, the curved surface portion 404 may be designed to provide a gradual transition from the radius of curvature R1 to the radius of curvature R2 using other shapes. For example, the radii forming the curved surface portion 404 may not have a common origin and may be of the same length. In such embodiments, the origin of each radius is moved along a helix to provide a gradual transition from the radius of curvature R1 to the radius of curvature R2. Additionally, in still other embodiments, the curved surface portion 404 may be formed from a plurality of small curved portions, each curved portion having a small arc length (e.g., 1 degree) and being defined by a constant radius that decreases with respect to the small curved portion adjacent to the foremost.

[0102] Referring now to FIGS. 8-18, an exemplary tibial insert 104 includes a body 800 that includes an asymmetric outer articular surface 122 and an inner articular surface 124. The inner articular surface 124 includes a Doell point 802 that defines the most distal point of the inner articular surface 124 and, generally, the point or area of contact where the medial condyle 114 of the femoral component 102 contacts the inner articular surface 124 during joint movement (however, some contact between the femoral component 102 and the tibial insert 104 may occur in front of the medial Doell point 802 at some flexion degrees and depending on the loading of the femoral component 102 and the tibial insert 104).

[0103] Exemplarily, the Doell point 802 is positioned on the inner articular surface 124 relative to the front wall 810 of the body 800 of the tibial insert 104. For example, in an exemplary embodiment, the Doell point 802 is defined on the inner articular surface 124 as a distance 820 that is about 63.3% of the total medial anteroposterior length 822 defined as the distance from the foremost point on the front wall 810 on the inner side of the body 800 of the tibial insert 104 to the rearmost point on the rear wall 812 (i.e., measured across the inner articular surface 124). It should be understood that in some embodiments, the outer articular surface 122 and the inner articular surface 124 may have different anteroposterior lengths because the rearmost points on the rear wall 812 are different.

[0104] Unlike the Doell point 802 of the inner articular surface 124, the outer articular surface 122 includes a Doell region 804 (shown by a solid line in FIG. 8) that defines the most distal region of the outer articular surface 122. Since the Doell region 804 corresponds to a generally planar or quasi-flat portion of the "sagittal" curvature of the outer articular surface 122, the Doell region 804 is embodied as a contact region. As used herein, the term "quasi-planar" refers to a surface that is planar or, otherwise, defined by a radius that is at least three times the length of the radius of curvature of adjacent curved portions, as described in more detail below. That is, the Doell region 804 may be embodied as a surface portion defined by a sufficiently large radius of curvature such that the curvature of the Doell region 804 approaches a planar portion when viewed in a cross-section along the arcuate joint path 806.

[0105] The trochlear region 804 is located on the arcuate joint path 806 of the outer joint surface 122, and the arcuate joint path defines the path of the contact point between the outer condyle 112 of the femoral component 102 and the outer joint surface 122 through the flexion of the femoral component 102 (however, the outer condyle 112 may not move along the complete arcuate joint path 806 during normal flexion). The arcuate path 806 is defined by a radius of curvature 808, which has an origin that coincides with or is within a reference distance from the trochlear point 802 of the inner joint surface 124. In an exemplary embodiment, the length of the radius of curvature 808 is designed to match within manufacturing tolerances the pitch of the condyles 112, 114 of the femoral component 102 (i.e., the distance between the most distal points at each condyle 112, 114). Thus, the curvature of the outer joint surface 122 is designed such that the femoral component 102 can pivot or rotate relative to the trochlear point 802 along the arcuate joint path 806 during flexion of the femoral component 102. That is, when the femoral component 102 is moved from extension to flexion, the contact point between the outer condyle 112 of the femoral component 102 and the outer joint surface 122 moves rearward along the arcuate path 806.

[0106] Similar to the trochlear point 802, the trochlear point 804 is, illustratively, positioned on the outer joint surface 122 relative to the front wall 810 of the body 800 of the tibial insert 104. For example, in an exemplary embodiment, the trochlear point 804 is defined as the distance of approximately 62.6% of the total outer anteroposterior length 922 (i.e., measured across the outer joint surface 122) from the foremost point on the front wall 810 on the outside of the body 800 of the tibial insert 104 to the rearmost point on the rear wall 812 on the outer joint surface 122. Again, it should be understood that in some embodiments, the outer joint surface 122 and the inner joint surface 124 may have different anteroposterior lengths because the rearmost points on the rear wall 812 are different.

[0107] In addition, as shown in FIG. 9, the Doyle point 802 of the inner joint surface 124 is spatially related to the Doyle region 804 of the outer joint surface 122. Specifically, the Doyle region 804 has a length 900 defined as the distance between the foremost end 902 of the Doyle region 804 (shown as a solid dot in FIG. 9) and the rearmost end 904 of the Doyle region 804 (similarly shown as a solid dot in FIG. 9), and the Doyle point 802 is located on the inner joint surface 124 between the foremost end 902 and the rearmost end 904 of the Doyle region 804. That is, the Doyle point 804 is located on the inner joint surface 124 between the forward virtual medial-lateral bisector 910 including the foremost end 902 of the Doyle region 804 and the rearward virtual medial-lateral bisector 912 including the rearmost end 904 of the Doyle region 804. In addition, as shown in FIG. 9, the Doyle point 804 is located on the inner joint surface 124 behind the midpoint 906 of the Doyle region 804 (shown as a solid dot in FIG. 9). That is, the Doyle point 804 is located on the inner joint surface 124 behind the virtual medial-lateral bisector 914 including the midpoint 906 of the Doyle region 804.

[0108] As shown in FIGS. 10 and 11, the body 800 of the tibial insert 104 includes a bottom surface 1000 configured to face the platform of a tibial tray (not shown) during implantation, as described above. An exemplary tibial insert 104 includes a rear channel 1002 sized and shaped to receive a rear buttress of the tibial tray. The rear channel 1002 is defined by side walls 1004, which include flanges 1006 that extend inwardly within the rear channel 1002 and are disposed to be received within an undercut of the corresponding tibial tray. The tibial insert 104 also includes a front channel 1010 sized and shaped to receive a front buttress of the corresponding tibial tray. In this way, the channels 1002, 1010 cooperate with features of the corresponding tibial tray to secure the tibial insert 104 onto the tibial tray in a single orientation relative to the tibial tray. In other embodiments, it should be understood that the tibial insert 104 and the corresponding tibial tray may include a movable bearing interface that allows the tibial insert 104 to move independently of the corresponding tibial tray. Additionally, as described above, the tibial insert 104 may be configured in some embodiments to be attached directly to the patient's tibia. In such embodiments, the tibial insert 104 may not include the above-described features for coupling to a tibial tray and may include other shapes that allow the tibial insert 104 to be implanted directly into the anatomical structure of the patient's bone.

[0109] As described above, the inner joint surface 124 and the outer joint surface 122 are asymmetric with respect to each other. For example, as best shown in FIGS. 12-17, the inner joint surface 124 has a front lip that is higher than the front lip of the outer joint surface 122. For example, as shown in FIG. 16, the outer joint surface 122 includes an outer front lip 1600 that defines a lip or rim of the front side wall 810 on the outer side. The outer front lip 1600 has a lip height 1602 defined by the vertical distance (i.e., the up and down distance) between the outer door point / region 804 of the tibial insert 104 and the outer front lip 1600. Similarly, as shown in FIG. 17, the inner joint surface 124 includes an inner front lip 1700 that defines a lip or rim of the front side wall 810 on the inner side. The inner front lip 1700 has a lip height 1702 defined by the vertical distance (i.e., the up and down distance) between the inner door point 802 of the tibial insert 104 and the inner front lip 1700. In an exemplary embodiment, the lip height 1702 of the inner front lip 1700 is higher than the lip height 1602 of the outer front lip 1600.

[0110] Furthermore, the door point 802 of the inner joint surface 124 is positioned such that the ratio of the distance 1710 between the inner door point 802 and the front side wall 810 to the lip height 1702 is relatively constant over the size of the tibial insert 104. For example, in an exemplary embodiment, the ratio of the lip height 1702 to the door point distance 1710 ranges from 18.9% to 20.9% depending on the size of the tibial insert 104.

[0111] Referring now to FIGS. 18 - 27, as described above, the outer joint surface 122 and the inner joint surface 124 have different contours such that the joint surfaces 122, 124 are asymmetric with respect to each other. For example, as shown in FIG. 18, the outer joint surface 122 includes a concave curvature 1802 when viewed in a combined anterior - posterior cross - section along the arcuate joint path 806. It should be understood that the combined anterior - posterior concave curvature 1802 of the arcuate joint path 806 does not lie on a single sagittal plane due to the arcuate shape of the arcuate joint path 806 when viewed in the horizontal plane. Additionally, the outer joint surface 122 has a concave curvature 1812 when viewed in a cross - section orthogonal to the arcuate joint path 806. The cross - sectional concave curvature 1812 is uniform at each point along the arcuate joint path 806 (shown by a plurality of concave curvatures 1812 in FIG. 18). That is, the cross - sectional concave curvature 1812 of the arcuate joint path 806 is generally uniform in the anterior - posterior direction along the arcuate joint path 806 (curving also in the medial - lateral direction due to the arcuate shape of the arcuate joint path 806). Again, it should be understood that the cross - sectional concave curvature 1812 does not directly lie on the coronal plane of the outer joint surface 122 due to the arcuate shape of the arcuate joint path 806 when viewed in the horizontal plane.

[0112] Conversely, the inner joint surface 124 is defined by a sagittal concave curvature 1804 and a plurality of non - uniform coronal curvatures 1814, 1824, 1834. However, as shown in FIG. 18, the coronal curvature of the inner joint surface 124 is uniform behind the inner doell point 802 and is defined by the coronal curvature 1814. Conversely, in front of the inner doell point 802, the coronal curvature of the inner joint surface is non - uniform and is defined by the coronal curvatures 1824 and 1834.

[0113] In some embodiments, the coronal conformity between the medial articular surface 124 and the medial condyle 114 is not uniform across the coronal curvatures 1814, 1824, 1834 and / or across the flexion of the femoral component 102 on the tibial insert 104. For example, in an exemplary embodiment, the coronal conformity between the medial articular surface 124 and the medial condyle 114 (i.e., the amount by which the radius of curvature defining the coronal curvature of the medial articular surface 124 at a particular contact point matches the radius of curvature defining the contact point (or region) of the condylar surface 400 of the medial condyle 114) is less between the coronal curvature 1814 and the condylar surface 400 of the medial condyle 114 at a particular flexion (e.g., 30.0 degrees of flexion) than between the coronal curvature 1824 or 1834 and the condylar surface 400 of the medial condyle 114 at the particular flexion. That is, at a particular flexion, the coronal conformity between the coronal curvature 1824 and the condylar surface 400 of the medial condyle 114 is greater than the coronal conformity between the coronal curvature 1814 (e.g., at the medial dovetail point 802) and the condylar surface 400 of the medial condyle 114. The coronal curvature of the medial articular surface 124 is designed to avoid collisions and / or unintended contacts between the femoral component 102 and the tibial insert 104, but it should also be understood that the coronal conformity between the medial articular surface 124 and the medial condyle 114 increases in front of the medial dovetail point 802 at a particular flexion (e.g., 30.0 degrees of flexion), so that the anterior translation of the medial condyle 114 can be restricted, limited, or otherwise reduced.

[0114] Referring now to FIG. 20, an exemplary embodiment of the anteroposterior compound concave curvature 1802 of the lateral articular surface 122 is shown in a cross-section of the tibial insert 104 generally along line 20-20 of FIG. 19 (i.e., along the arcuate joint path 806). The exemplary anteroposterior compound concave curvature 1802 includes a quasi-planar portion 2000 corresponding to the dovetail region 804, a first set of curved portions extending posteriorly from the flat portion 2000, and an anterior curved portion 2006 extending anteriorly from the flat portion 2000. The first set of curved portions illustratively includes a first curved portion 2002 and a second curved portion 2004.

[0115] As described above, the flat portion 2000 (i.e., the door region 804) is a quasi-plane and extends from the foremost end 902 to the rearmost end 904. Also in this case, the flat portion 2000 is "quasi-plane" in that it can be defined as a flat portion as shown in FIG. 20 or as a curved portion having a sufficiently large radius so as to approach the flat portion. For example, in an exemplary embodiment, the flat portion 2000 is defined by a large radius of curvature 2010 having a length at least three times the length of the radius of curvature that defines any adjacent curved portion (i.e., the curved portion 2012 and the curved portion 2016). In such an embodiment, the flat portion 2000 includes the door point 2090 that defines the farthest point of the flat portion 2000 and extends over an arc length of approximately 2.73 degrees in total, about 1.15 degrees in front of the door point 2090 and about 1.58 degrees behind the door point 2090.

[0116] Exemplarily, the first curved portion 2002 of the first set of curved portions extends rearward from the rearmost end 904 of the flat portion 2000 over an angle of about 3.4 degrees and is defined by a constant radius of curvature 2012. The second curved portion 2004 is adjacent to the first curved portion 2002 and extends rearward therefrom over an arc length in the range of about 13.2 degrees to about 13.7 degrees depending on the size of the tibial insert 104. The second curved portion 2004 is defined by a constant radius of curvature 2014. In an exemplary embodiment, the radius of curvature 2014 is smaller than the radius of curvature 2012 (i.e., the radius of curvature of the anterior-posterior compound concave curve 1802 decreases rearward). However, in other embodiments, the first set of curved portions extending rearward from the flat portion 2000 may include additional curved portions to smoothly open the rear side of the anterior-posterior compound concave curve 1802 and / or may be defined by a progressively or continuously decreasing radius as described above with respect to the femoral component 102.

[0117] The anterior curved portion 2006 extends forward from the foremost end 902 of the flat portion 2000 over an arc length in the range of about 33.5 degrees to about 34.4 degrees depending on the size of the tibial insert 104. In an exemplary embodiment, the radius of curvature 2016 is smaller than the radius of curvature 2012 and larger than the radius of curvature 2014.

[0118] Referring now to FIG. 21, in another embodiment, the anterior-posterior compound concave curvature 1802 may include a flat or planar portion 2100 corresponding to the dovetail region 804, a first set of curved portions extending rearward of the flat portion 2100, and a second set of curved portions extending forward of the flat portion 2100. As described above, the flat portion 2100 (i.e., the dovetail region 804) extends from the foremost end 902 to the rearmost end 904.

[0119] The first set of curved portions illustratively includes a first curved portion 2102, a second curved portion 2104, a third curved portion 2106, and a fourth curved portion 2108. The first curved portion 2102 extends over approximately 5.0 degrees and is defined by a constant radius of curvature 2122. The second curved portion 2104 extends over approximately 5.0 degrees and is defined by a constant radius of curvature 2124. The third curved portion 2106 extends over approximately 5.0 degrees and is defined by a constant radius of curvature 2126. Also, the fourth curved portion 2108 extends over 18.0 degrees and is defined by a constant radius of curvature 2128. However, in some embodiments, the first set of curved portions extending rearward from the flat portion 2100 may include additional curved portions to smoothly open the rear side of the anterior-posterior compound concave curvature 1802 and / or, as described above with respect to the femoral component 102, may be defined by a progressively or continuously decreasing radius. In an exemplary embodiment, the radius of curvature of the first set of curved portions increases rearwardly. That is, the radius of curvature 2128 is greater than the radius of curvature 2126, the radius of curvature 2126 is greater than the radius of curvature 2124, and the radius of curvature 2124 is greater than the radius of curvature 2122.

[0120] The second set of curved portions illustratively includes a fifth curved portion 2110 and a sixth curved portion 2112. The fifth curved portion 2110 extends over approximately 15.0 degrees and is defined by a radius of curvature 2130. Also, the sixth curved portion 2112 extends over approximately 35.0 degrees and is defined by a radius of curvature 2132. In an exemplary embodiment, the radius of curvature 2130 is greater than the radius of curvature 2132.

[0121] Referring now to FIG. 22, an exemplary embodiment of the medial sagittal concave curvature 1804 of the tibial insert 104 is shown in a cross-section generally along line 22-22 of FIG. 19 which generally corresponds to the sagittal concave curvature 1804 of FIG. 18. The exemplary medial sagittal concave curvature 1804 includes a first curved portion 2200, a second curved portion 2202 adjacent to the front of the first curved portion 2200, a third curved portion 2204 adjacent to the front of the second curved portion 2202, a fourth curved portion 2206 adjacent to the front of the third curved portion, and a fifth curved portion 2208 adjacent to the rear of the first curved portion 2200. Illustratively, the medial door point 802 is present at the intersection of the first curved portion 2200 and the fifth curved portion 2208. However, in other embodiments, the door point 802 may be present on the first curved portion 2200 or the fifth curved portion 2208.

[0122] The first curved portion 2200 extends forward from the femoral point 802 over approximately 5.2 degrees and is defined by a constant radius of curvature 2210. The second curved portion 2202 extends forward from the first curved portion 2200 over an arc length in the range of approximately 14.8 degrees to approximately 24.8 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2212. The third curved portion 2204 extends forward from the second curved portion 2202 over an arc length in the range of approximately 10.7 degrees to approximately 20.7 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2214. The fourth curved portion 2206 extends forward from the third curved portion 2204 over an arc length in the range of approximately 0.2 degrees to approximately 6.3 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2216. Also, the fifth curved portion 2208 extends rearward from the first curved portion 2200 over an arc length in the range of approximately 15.9 degrees to approximately 17.4 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2218. In an exemplary embodiment, the radius of curvature 2218 is greater than the radius of curvature 2210. Further, in an exemplary embodiment, the radius of curvature 2212 is smaller than each of the radii of curvature 2210, 2214, and 2216.

[0123] The medial sagittal concave curvature 1804 of the tibial insert 104 may be shaped into a different shape so as to have a different curvature in other embodiments. For example, in another embodiment, the second curved portion 2202 may extend forward from the first curved portion 2200 over approximately 24.8 degrees. The third curved portion 2204 may extend forward from the second curved portion 2202 over approximately 15.0 degrees. Also, the fifth curved portion 2208 may extend rearward from the first curved portion 2200 over approximately 19.0 degrees.

[0124] In some embodiments, the sagittal conformity between the medial articular surface 124 and the medial condyle 114 is not uniform over the range of flexion. For example, as will be described in more detail below with respect to FIGS. 28-43, the overall sagittal conformity between the medial sagittal concave curvature 1804 of the tibial insert 104 and the sagittal convex curvature of the medial condyle 114 of the femoral component 102 may be greater at a particular flexion angle (e.g., 30 degrees of flexion) than in extension. The overall sagittal conformity between the sagittal curvatures of the femoral component 102 and the tibial insert 104 (i.e., conformity over the complete sagittal curvature, not just at specific contact points) can be defined as the amount of the overall gap between these curvatures at a particular flexion angle. Thus, the sagittal curvature of the medial condyle 114 of the femoral component 102 matches the sagittal curvature of the medial articular surface 124 of the tibial insert at a particular flexion angle (e.g., 30 degrees of flexion) by a maximum amount. The sagittal conformity can further increase under load conditions (i.e., the sagittal conformity at a particular flexion angle is further increased by the femoral component 102 being further pressed against the tibial insert 104). By the overall sagittal conformity between the medial condyle 114 and the medial articular surface 124 increasing during flexion compared to extension, the anterior translation of the femoral component 102 on the medial articular surface 124 can be reduced at that particular flexion angle (e.g., 30 or 35 degrees of flexion).

[0125] In addition, at a specific degree of flexion (e.g., 30 degrees of flexion), the sagittal conformity between the medial condyle 114 and the sagittal curvatures 2200, 2202, 2204, 2206. For example, in an exemplary embodiment, the sagittal conformity between the medial articular surface 124 and the medial condyle 114 (i.e., the amount by which the radius of curvature defining the sagittal curvature of the medial articular surface 124 at a specific contact point matches the radius of curvature defining the contact point on the condylar surface 400 of the medial condyle 114) is less between the first curvature portion 2200 and the condylar surface 400 of the medial condyle 114 at a specific degree of flexion (e.g., 30.0 degrees of flexion) than between the fourth curvature portion 2206 and the condylar surface 400 of the medial condyle 114 at the specific degree of flexion. That is, at a specific degree of flexion, the sagittal conformity at the contact point (or region) between the first curvature portion 2200 and the condylar surface 400 of the medial condyle 114 is greater than the sagittal conformity at the contact point (or region) between the fourth curvature portion 2206 and the condylar surface 400 of the medial condyle 114. Thus, it should be understood that the sagittal conformity between the medial articular surface 124 and the medial condyle 114 increases in front of the medial door point 802 at a specific degree of flexion (e.g., 30.0 degrees of flexion), so that the forward translational movement of the medial condyle 114 on the medial articular surface 124 can be restricted, limited, or otherwise reduced.

[0126] In addition, it should be understood that the sagittal conformity between the medial articular surface 124 and the medial condyle 114 at the medial door point 802 can increase through a specific flexion range in some embodiments. For example, in an exemplary embodiment, as the femoral component 102 is flexed through a specific flexion range, the contact point between the femoral component 102 and the tibial insert 104 moves along a curved surface portion 404 defined by a decreasing radius of curvature. Thus, in an exemplary embodiment, the sagittal curvature of the medial articular surface 124 at the medial door point 802 is designed to have a maximum amount of sagittal conformity with the medial condyle 114 at a specific degree of flexion (e.g., 30 degrees of flexion) at which the contact point between the femoral component 102 and the tibial insert 104 occurs on the curved surface portion 404, and as a result, the amount of sagittal conformity between the femoral component 102 and the tibial insert 104 increases as the specific degree of flexion is approached.

[0127] Referring now to FIG. 23, an exemplary embodiment of the cross-sectional concave curvature 1812 of the outer articular surface 122 of the tibial insert 104 is shown in a cross-section generally along line 23-23 of FIG. 19, which generally corresponds to the uniform cross-sectional curvature 1812 of FIG. 18. As described above, in the exemplary embodiment, the cross-sectional curvature 1812 of the outer articular surface 122 is uniform along the anterior-posterior composite concave curvature 1802 and has a single curved portion 2300 with a constant radius of curvature 2302. The curved portion 2300 extends approximately 25 degrees inward (i.e., closer to the inside) of the outer dovetail region 804 and extends over an arc length in the range of approximately 18.7 degrees to approximately 31.1 degrees outward (i.e., closer to the outside) of the outer dovetail region 804, with the total arc length being approximately 43.7 degrees to approximately 56.1 degrees, depending on the size of the tibial insert 104. Additionally, the cross-sectional curvature 1812 of the outer articular surface 122 includes a planar portion 2310 that extends inward (i.e., closer to the inside) in contact with the innermost point of the curved portion 2300. Additionally, as shown in FIG. 23, the planar portion 2310 is inclined at an angle 2320 of approximately 25.0 degrees with respect to the bottom surface 1000 of the tibial insert 104. The size, shape, and orientation of the planar portion 2310 may be selected or designed to match the inner shape of the femoral component 102 and / or to avoid collision with the femoral component 102.

[0128] Referring now to FIG. 24, an exemplary embodiment of the coronal curvature 1814 of the tibial insert 104 is shown in a cross-section generally along line 24-24 of FIG. 19, which generally corresponds to the coronal curvature 1814 of FIG. 18. In the exemplary embodiment, the coronal curvature 1814 of the inner articular surface 124 is uniform behind the inner dovetail point 802 and has a single curved portion 2400 with a constant radius of curvature 2402.

[0129] The curved portion 2400 extends approximately 25 degrees outward (i.e., closer to the medial side) from the medial door point 802 according to the size of the tibial insert 104, and extends over an arc length in the range of approximately 18.6 degrees to approximately 26.8 degrees inward (i.e., closer to the lateral side) from the medial door point 802, with the total arc length being approximately 43.6 degrees to approximately 51.8 degrees. In addition, the coronal curvature 1814 of the medial articular surface 124 includes a planar portion 2410 that contacts the outermost point of the curved portion 2400 and extends outward (i.e., closer to the medial side) therefrom. As shown in FIG. 24, the planar portion 2410 is inclined at an angle 2420 of approximately 25.0 degrees with respect to the bottom surface 1000 of the tibial insert 104. Similar to the planar portion 2310 of the lateral articular surface 122, the size, shape, and orientation of the planar portion 2410 may be selected or designed to match the inner shape of the femoral component 102 and / or to avoid collision with the femoral component 102.

[0130] In other embodiments, the coronal curvature 1814 may be defined by a plurality of curved portions. For example, as shown in FIG. 25, in another embodiment, the coronal curvature 1814 may be defined by a first curved portion 2500 where the door point 802 is located, and a second curved portion 2502 that is adjacent to the inside (i.e., closer to the lateral side) of the first curved portion 2500. The first curved portion 2500 extends over approximately 20 degrees and is defined by a radius of curvature 2510, and the second curved portion 2502 extends over approximately 10 degrees and is defined by a radius of curvature 2512. In such an embodiment, the radius of curvature 2512 may be larger than the radius of curvature 2510. In addition, the coronal curvature 1814 of FIG. 25 may include a planar portion 2504 that contacts the outermost point of the curved portion 2500 and extends outward (i.e., closer to the medial side) therefrom. Similar to the planar portion 2410, the planar portion 2504 may be inclined at an angle of approximately 25.0 degrees with respect to the bottom surface 1000 of the tibial insert 104.

[0131] Referring now to FIG. 26, an exemplary embodiment of the coronal curvature 1824 of the tibial insert 104 is shown in a cross-section generally along line 26-26 of FIG. 19, which generally corresponds to the coronal curvature 1824 of FIG. 18. The coronal curvature 1824 intersects the sagittal concave curvature 1804 at the foremost point of the second curved portion 2202 that defines the medial sagittal concave curvature 1804 (see FIG. 22). The coronal curvature 1824 includes a flat or planar portion 2600 having an outer end 2602 (i.e., the inner-side end) and an inner end 2604 (i.e., the outer-side end), a first curved portion 2606 extending from the inner end 2604 of the planar portion 2600, and a second curved portion 2608 extending from the outer end 2602 of the planar portion 2600. The first curved portion 2606 extends over an arc length in the range of about 14.7 degrees to about 15.7 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2616. The second curved portion 2608 extends over an arc length in the range of about 20.1 degrees to about 28.5 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2618. In an exemplary embodiment, the radius of curvature 2618 is larger than the radius of curvature 2616.

[0132] Referring now to FIG. 27, an exemplary embodiment of the coronal curvature 1834 of the tibial insert 104 is shown in a cross-section generally along line 27-27 of FIG. 19, which generally corresponds to the coronal curvature 1834 of FIG. 18. The coronal curvature 1834 intersects the sagittal concave curvature 1804 at the foremost point of the third curved portion 2204 that defines the medial sagittal concave curvature 1804 (see FIG. 22). Similar to the coronal curvature 1824, the coronal curvature 1834 includes a flat or planar portion 2700 having an outer end 2702 (i.e., the inner-side end) and an inner end 2704 (i.e., the outer-side end), a first curved portion 2706 extending from the inner end 2704 of the planar portion 2700, and a second curved portion 2708 extending from the outer end 2702 of the planar portion 2700. In some embodiments, the planar portion 2700 may be inclined at about 6.0 degrees with respect to the bottom surface 1000 of the tibial insert 104. The first curved portion 2706 extends over an arc length in the range of about 0.3 degrees to about 0.9 degrees depending on the size of the tibial insert 104 and is defined by a constant radius of curvature 2616. The second curved portion 2708 extends over an arc length in the range of about 16.4 degrees to about 24.7 degrees depending on the size of the tibial insert 104 and is defined by a constant radius of curvature 2718. In an exemplary embodiment, the radius of curvature 2716 is larger than the radius of curvature 2718.

[0133] Referring now to FIGS. 28-43, as described above, the femoral component 102 is configured to articulate on the tibial insert 104 through a range of flexion degrees. For example, in FIG. 28, the femoral component 102 at extension (i.e., 0 degrees of flexion) is shown. In FIG. 29, the femoral component 102 is undergoing articulation up to about 35 degrees of flexion. In FIG. 30, the femoral component 102 is undergoing articulation up to about 90 degrees of flexion. Also, in FIG. 31, the femoral component 102 is undergoing articulation up to about 110 degrees of flexion.

[0134] As described above, the condyles 112, 114 of the femoral component 102 may have different amounts of conformity with the articular surfaces 122, 124 at different flexion degrees. For example, FIGS. 32-34 show the orthopedic prosthesis 100 at about 0.0 degrees of flexion. As shown in FIG. 32, the femoral component 102 and the tibial insert 104 have increased coronal conformity when in the extended state. Further, as shown in FIG. 33, the femoral component 102 is pivoting or rotating only slightly on the tibial insert 104. Further, as shown in FIG. 34, the medial condyle 114 and the medial articular surface 124 have an overall sagittal conformity (i.e., the amount of space between the sagittal curvatures of the medial condyle 114 and the medial articular surface 124) when extended.

[0135] FIGS. 35-37 show the orthopedic prosthesis 100 at 35.0 degrees of flexion. As shown in FIG. 35, the femoral component 102 and the tibial insert 104 have slightly less coronal conformity compared to the extended position. In addition, as shown in FIG. 36, the femoral component 102 is pivoting or rotating to a greater amount on the tibial insert 104. Further, as shown in FIG. 37, the medial condyle 114 and the medial articular surface 124 have an increased overall sagittal conformity compared to the 0.0 degree flexion of FIG. 34.

[0136] FIGS. 38-40 show the orthopedic prosthesis 100 at about 90 degrees of flexion. As shown in FIG. 38, the femoral component 102 and the tibial insert 104 have less coronal conformity compared to the 35 degree flexion of FIGS. 34 and 35. In addition, as shown in FIG. 39, the femoral component 102 is pivoting or rotating to a greater amount on the tibial insert 104 compared to the 35 degree flexion of FIGS. 35 and 36. Further, as shown in FIG. 40, the medial condyle 114 and the medial articular surface 124 have a decreased overall sagittal conformity compared to the 35.0 degree flexion of FIG. 37.

[0137] Figures 41 to 43 show the orthopedic prosthesis 100 at a flexion of about 110 degrees. As shown in Figure 41, the femoral component 102 and the tibial insert 104 have less coronal conformity compared to the 90-degree flexion in Figures 38 and 39. In addition, as shown in Figure 42, the femoral component 102 pivots or rotates on the tibial insert 104 to a greater extent compared to the 90-degree flexion in Figures 38 and 39. Further, as shown in Figure 43, the medial condyle 114 and the medial articular surface 124 have further reduced overall sagittal conformity compared to the 90.0-degree flexion in Figure 40.

[0138] Referring now to Figures 44 and 45, as the femoral component 102 is moved through the flexion range, the condylar surface 400 of the medial condyle 114 contacts the medial dovetail point 802 of the tibial insert 104 at different contact points on the condylar surface 400. For example, in an exemplary embodiment, as the femoral component 102 moves from about 65 degrees of flexion to a flexion greater than 65 degrees, the contact point between the femoral component 102 and the tibial insert 104 moves from the curved surface portion 404 defined by a decreasing radius of curvature to the curved surface portion 406 defined by a radius of curvature greater than the most posterior radius of curvature of the curved surface portion 404. By doing so, the distance between the origins defining the radius of curvature of the contact point between the femoral component 102 and the tibial insert increases.

[0139] For example, Figure 44 shows the femoral component 102 at a first degree of flexion where the contact point 4400 between the condylar surface 400 of the medial condyle 114 of the femoral component 102 and the tibial insert 104 is located at the dovetail point 802 of the tibial insert 104 and is defined by the most posterior radius 4402 of a plurality of decreasing radii that define the curved surface portion 404. The most posterior radius 4402 has an origin 4404 located at a distance 4410 from the medial dovetail point 802.

[0140] In FIG. 45, the femoral component 102 is moved to a second flexion degree that is slightly greater than the first flexion degree. At this flexion degree, the contact point 4500 between the femoral surface 400 of the medial condyle 114 of the femoral component 102 and the tibial insert 104 is located at the dovetail point 802 of the tibial insert 104 and is defined by a constant radius of curvature 4502 (i.e., the radius of curvature R3 in FIG. 4) that defines the curved surface portion 406. The constant radius of curvature 4502 has an origin 4504 that is located at a distance 4510 from the medial dovetail point 802. It should be understood that the distance 4510 between the origin 4504 and the medial dovetail point 802 is greater than the distance 4410 between the origin 4404 and the medial dovetail point 802. Therefore, due to the increase in the distance between the origins 4404 and 4504 when the contact point between the femoral component 102 and the tibial insert 104 moves from the curved surface portion 404 to the curved surface portion 406 of the femoral surface 400 of the medial condyle 114, the tibio-femoral envelope elongates, thereby increasing the tension in the ligaments of the knee joint and improving the stability of the knee joint.

[0141] As described above, the present disclosure has been illustrated and described in detail in the drawings and the above description. However, such illustrations and descriptions should be regarded as exemplary in nature and not as restrictive, and are merely illustrative of exemplary embodiments and not intended to limit the scope of the present disclosure. It should be understood that all modifications and changes within the scope of the present disclosure are desired to be protected.

[0142] The present disclosure has a plurality of advantages based on various features of the methods, apparatuses, and / or systems described herein. It should be noted that alternative embodiments of the methods, apparatuses, and systems of the present disclosure do not include all of the features described, but still enjoy at least some of the advantages of such features. Those skilled in the art can easily implement independently the methods, apparatuses, and systems that incorporate one or more of the features of the present invention and are included within the spirit and scope of the present disclosure as defined in the appended "claims".

[0143] 〔Embodiment〕 (1) A tibial insert, comprising: an outer joint surface configured to articulate with the outer condyle of the femoral component and including an arcuate joint path extending in the anterior-posterior direction, the arcuate joint path being defined by a plurality of points on the outer joint surface, each point defining the most distal point of the outer joint surface in the corresponding medial and lateral cross-sections when the tibial insert is viewed in the medial and lateral cross-sections at each point, the outer joint surface having a cross-sectional concave curvature orthogonal to the arcuate joint path, the cross-sectional concave curvature being uniform at each of the plurality of points; and an inner joint surface configured to articulate with the inner condyle of the femoral component, the inner joint surface being asymmetrically shaped relative to the outer joint surface and having a non-uniform coronal concave curvature in the anterior-posterior direction. (2) The tibial insert according to embodiment 1, wherein the inner joint surface includes an inner dome point that defines the most distal point of the inner joint surface, and the coronal concave curvature of the inner joint surface is non-uniform in front of the inner dome point and uniform behind the inner dome point. (3) The arcuate joint path has a curvature including a quasi-planar portion, a forwardly curved portion located in front of the planar portion, and a plurality of rearwardly curved portions located behind the planar portion when viewed in cross-section. The tibial insert according to embodiment 1, wherein the quasi-planar portion defines an outer dome region that defines the most distal region of the outer joint surface. (4) The tibial insert according to embodiment 3, wherein each of the plurality of rearwardly curved portions is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly. (5) The tibial insert according to embodiment 3, wherein the plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, and the radius of curvature of the first rearwardly curved portion is greater than the radius of curvature of the second rearwardly curved portion.

[0144] (6) The anterior curved portion is defined by a corresponding radius of curvature that is (i) smaller than the radius of curvature of the first posterior curved portion and (ii) larger than the radius of curvature of the second posterior curved portion, of the tibial insert according to Embodiment 5. (7) The anterior curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first posterior curved portion extends over about 3.4 degrees, and the second posterior curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees, of the tibial insert according to Embodiment 5. (8) The medial articular surface includes a sagittal concave curvature defined by a plurality of curved portions when viewed in the sagittal plane and a medial dome point that defines the most distal point of the medial articular surface, and the medial dome point is located on the sagittal concave curvature, of the tibial insert according to Embodiment 1. (9) The plurality of curved portions includes a first curved portion that extends rearward from adjacent to the medial dome point and a second curved portion that extends forward from adjacent to the medial dome point, and the radius of curvature of the first curved portion is larger than the radius of curvature of the second curved portion, of the tibial insert according to Embodiment 8. (10) The first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over about 5.2 degrees, of the tibial insert according to Embodiment 9.

[0145] (11) The plurality of curved portions includes a third curved portion that extends forward from adjacent to the second curved portion, a fourth curved portion that extends forward from adjacent to the third curved portion, and a fifth curved portion that extends forward from adjacent to the fourth curved portion, and the radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth curvature radius, of the tibial insert according to Embodiment 9. (12) The third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length in the range of 0.2 degrees to 6.3 degrees, the tibial insert according to Embodiment 11. (13) The coronal concave curvature of the medial articular surface is defined by a plurality of coronal curvatures including a first coronal curvature that intersects the sagittal concave curvature of the medial articular surface at the medial dovetail point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first coronal curvature, the second coronal curvature, and the third coronal curvature is different from each other, the tibial insert according to Embodiment 11. (14) The first coronal curvature is defined by a coronal curved portion that extends over an arc length in the range of 18.6 degrees to 26.8 degrees inward from the medial dovetail point and extends outward from the medial dovetail point by about 25.0 degrees, the tibial insert according to Embodiment 13. (15) The second coronal curvature intersects the sagittal concave curvature of the medial articular surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the medial articular surface, and the second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion, the tibial insert according to Embodiment 13.

[0146] (16) The radius of curvature of the first coronal curved portion of the second coronal curvature is smaller than the radius of curvature of the second coronal curved portion of the second coronal curvature, the tibial insert according to Embodiment 15. (17) The first coronal curvature of the second coronal curved portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curved portion of the second coronal curvature extends over an arc length in the range of 20.1 degrees to 28.5 degrees, the tibial insert according to Embodiment 16. (18) The third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. The tibial insert according to embodiment 15. (19) The planar portion of the third coronal curvature forms an angle of about 6 degrees with the bottom surface of the tibial insert. The tibial insert according to embodiment 18. (20) The first coronal curved portion of the third coronal curvature extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curvature extends over an arc length in the range of 16.4 degrees to 24.7 degrees. The tibial insert according to embodiment 19.

[0147] (21) Further including a front side wall and a rear side wall opposite to the front side, the distance between the front side wall and the rear side wall defines the anteroposterior length of the tibial insert. The inner joint surface includes an inner dovetail point that defines the most distal point of the inner joint surface. The inner dovetail point is located at about 63.3% of the anteroposterior length from the front end. The tibial insert according to embodiment 1. (22) The inner joint surface includes an inner dovetail point that defines the most distal point of the inner joint surface. The arcuate joint path of the outer joint surface is defined by a radius of curvature having an origin on the inner dovetail point when viewed in the horizontal plane. The tibial insert according to embodiment 1. (23) Further including a first portion of a locking mechanism located on the bottom surface of the tibial insert, the first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base. The tibial insert according to embodiment 1. (24) A tibial insert, An outer articular surface configured to articulate with the outer condyle of the femur component and including an arcuate articular path extending in the anteroposterior direction, wherein the arcuate articular path has a curvature including a planar portion when viewed in cross-section, and the planar portion defines the most distal region of the outer articular surface, the outer articular surface, and An inner articular surface configured to articulate with the inner condyle of the femur component, wherein the inner articular surface is shaped asymmetrically with respect to the outer articular surface and includes an inner dome point defining the most distal point of the inner condyle surface, and the inner dome point is on the inner condyle surface, (i) between a first virtual medial-lateral bisector of the tibial insert including the most anterior end of the planar portion of the sagittal curvature of the outer articular surface and a second virtual medial-lateral bisector of the tibial insert including the most posterior end of the planar portion of the sagittal curvature of the outer articular surface, and (ii) located posterior to the anteroposterior midpoint of the planar portion of the sagittal curvature of the outer articular surface, the inner articular surface, including a tibial insert. (25) Further including a front wall and a rear wall opposite to the front side, and a distance between the front wall and the rear wall defines the anteroposterior length of the tibial insert, The tibial insert according to embodiment 24, wherein the inner dome point is located at a position about 63.3% of the anteroposterior length from the front end.

[0148] (26) The inner articular surface has a non-uniform curvature in front of the inner dome point and a uniform coronal concave curvature behind the inner dome point, the tibial insert according to embodiment 24. (27) The curvature of the arcuate articular path further includes a front curved portion located in front of the planar portion and a plurality of rear curved portions located behind the planar portion when viewed in the cross-section, the tibial insert according to embodiment 24. (28) Each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rear curved portions decrease rearward, the tibial insert according to embodiment 27. (29) The plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, and a radius of curvature of the first rearwardly curved portion is larger than a radius of curvature of the second rearwardly curved portion. The tibial insert according to Embodiment 27. (30) The forwardly curved portion is defined by a corresponding radius of curvature that is (i) smaller than the radius of curvature of the first rearwardly curved portion and (ii) larger than the radius of curvature of the second rearwardly curved portion. The tibial insert according to Embodiment 29.

[0149] (31) The forwardly curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first rearwardly curved portion extends over about 3.4 degrees, and the second rearwardly curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees. The tibial insert according to Embodiment 29. (32) The medial articular surface includes a sagittal concave curvature defined by a plurality of curved portions when viewed in a sagittal plane, and the medial dome point is located on the sagittal concave curvature. The tibial insert according to Embodiment 24. (33) The plurality of curved portions includes a first curved portion adjacent to and extending rearwardly from the medial dome point and a second curved portion adjacent to and extending forwardly from the medial dome point, and a radius of curvature of the first curved portion is larger than a radius of curvature of the second curved portion. The tibial insert according to Embodiment 32. (34) The first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over about 5.2 degrees. The tibial insert according to Embodiment 33. (35) The plurality of curved portions include a third curved portion that is adjacent to the second curved portion and extends forward therefrom, a fourth curved portion that is adjacent to the third curved portion and extends forward therefrom, and a fifth curved portion that is adjacent to the fourth curved portion and extends forward therefrom. The radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth radius of curvature. The tibial insert according to Embodiment 33.

[0150] (36) The third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length in the range of 0.2 degrees to 6.3 degrees. The tibial insert according to Embodiment 35. (37) The medial articular surface has a coronary curvature defined by a plurality of coronary curves, including a first coronary curve that intersects the sagittal concave curve of the medial articular surface at the medial doell point, a second coronary curve located in front of the first coronary curve, and a third coronary curve located in front of the second coronary curve. Each of the first coronary curve, the second coronary curve, and the third coronary curve is different from each other. The tibial insert according to Embodiment 35. (38) The first coronary curve is defined by a coronary curved portion that extends over an arc length in the range of 18.6 degrees to 26.8 degrees inward from the medial doell point and extends outward from the medial doell point by about 25.0 degrees. The tibial insert according to Embodiment 37. (39) The second coronary curve intersects the sagittal concave curve of the medial articular surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curve of the medial articular surface. The second coronary curve is defined by a planar portion having an inner end and an outer end, a first coronary curved portion extending from the inner end of the planar portion, and a second coronary curved portion extending from the outer end of the planar portion. The tibial insert according to Embodiment 37. (40) The radius of curvature of the first coronal curvature portion of the second coronal curvature is smaller than the radius of curvature of the second coronal curvature portion of the second coronal curvature, the tibial insert according to Embodiment 39.

[0151] (41) The first coronal curvature of the second coronal curvature portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length in the range of 20.1 degrees to 28.5 degrees, the tibial insert according to Embodiment 40. (42) The third coronal curvature intersects the sagittal concave curvature of the medial articular surface at the foremost point of the fourth curvature portion among the plurality of curvature portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curvature portion extending from the inner end of the planar portion, and a second coronal curvature portion extending from the outer end of the planar portion, the tibial insert according to Embodiment 39. (43) The planar portion of the third coronal curvature forms an angle of about 6 degrees with respect to the bottom surface of the tibial insert, the tibial insert according to Embodiment 40. (44) The first coronal curvature portion of the third coronal curvature extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curvature portion of the third coronal curvature extends over an arc length in the range of 24.6 degrees to 16.5 degrees, the tibial insert according to Embodiment 43. (45) The arcuate joint path is defined by a radius of curvature having an origin on the medial door point when viewed in the horizontal plane, the tibial insert according to Embodiment 24.

[0152] (46) Further including a first portion of a locking mechanism located on the bottom surface of the tibial insert, the first portion of the locking mechanism being configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base, the tibial insert according to Embodiment 24. (47) A tibial insert, An outer articular surface configured to articulate with the outer condyle of the femur component, the outer articular surface including an arcuate articular path extending in the anteroposterior direction, an outer dovetail point defining the most distal point on the outer articular surface located on the arcuate articular path, and an anterior lateral lip, the vertical distance between the outer dovetail point and the uppermost point of the anterior lateral lip defining the lip height of the anterior lateral lip, the outer articular surface, and An inner articular surface configured to articulate with the inner condyle of the femur component, the inner articular surface being asymmetrically shaped with respect to the outer articular surface, the inner articular surface including an inner dovetail point defining the most distal point on the inner articular surface, and an anterior medial lip, the vertical distance between the inner dovetail point and the uppermost point on the inner lateral lip defining the lip height of the anterior medial lip, the inner articular surface, and (i) The lip height of the anterior medial lip is higher than the lip height of the anterior lateral lip, and (ii) the ratio of the lip height of the anterior medial lip to the anteroposterior distance between the anterior side wall and the posterior side wall of the inner articular surface is in the range of 18.9% to 20.9%, a tibial insert. (48) The inner articular surface has a non-uniform curvature concave in the coronal plane in front of the inner dovetail point and a uniform curvature concave in the coronal plane behind the inner dovetail point, the tibial insert according to embodiment 47. (49) The arcuate articular path has a curvature including a quasi-planar portion when viewed in cross-section, an anterior curved portion located in front of the planar portion, and a plurality of posterior curved portions located behind the planar portion, The outer dovetail point is located in the quasi-planar portion, the tibial insert according to embodiment 47. (50) Each posterior curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of posterior curved portions decrease posteriorly, the tibial insert according to embodiment 49.

[0153] (51) The plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, and the radius of curvature of the first rearwardly curved portion is greater than the radius of curvature of the second rearwardly curved portion. The tibial insert according to Embodiment 49. (52) The forwardly curved portion is defined by a corresponding radius of curvature that is (i) less than the radius of curvature of the first rearwardly curved portion and (ii) greater than the radius of curvature of the second rearwardly curved portion. The tibial insert according to Embodiment 51. (53) The forwardly curved portion extends over an arc length in the range of 33.5 degrees to 34.4 degrees, the first rearwardly curved portion extends over about 3.4 degrees, and the second rearwardly curved portion extends over an arc length in the range of 13.2 degrees to 13.7 degrees. The tibial insert according to Embodiment 5. (54) The inner articular surface includes a sagittal concave curvature defined by a plurality of curved portions when viewed in the sagittal plane, and the inner dovetail point is located on the sagittal concave curvature. The tibial insert according to Embodiment 47. (55) The plurality of curved portions includes a first curved portion adjacent to and extending rearward from the inner dovetail point and a second curved portion adjacent to and extending forward from the inner dovetail point, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. The tibial insert according to Embodiment 54.

[0154] (56) The first curved portion extends over an arc length in the range of 15.9 degrees to 17.4 degrees, and the second curved portion extends over about 5.2 degrees. The tibial insert according to Embodiment 55. (57) The plurality of curved portions include a third curved portion that is adjacent to the second curved portion and extends forward therefrom, a fourth curved portion that is adjacent to the third curved portion and extends forward therefrom, and a fifth curved portion that is adjacent to the fourth curved portion and extends forward therefrom. The radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth curved portion. The tibial insert according to Embodiment 55. (58) The third curved portion extends over an arc length in the range of 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length in the range of 10.7 degrees to 20.7 degrees, and the fifth curved portion extends over an arc length in the range of 0.2 degrees to 6.3 degrees. The tibial insert according to Embodiment 57. (59) The medial articular surface has a coronary curvature defined by a plurality of coronary curvatures, including a first coronary curvature that intersects the sagittal concave curvature of the medial articular surface at the medial dovetail point, a second coronary curvature located in front of the first coronary curvature, and a third coronary curvature located in front of the second coronary curvature. Each of the first coronary curvature, the second coronary curvature, and the third coronary curvature is different from each other. The tibial insert according to Embodiment 57. (60) The first coronary curvature is defined by a coronary curved portion that extends over an arc length in the range of 18.6 to 26.8 degrees inward from the medial dovetail point and extends outward by about 25.0 degrees from the medial dovetail point. The tibial insert according to Embodiment 59.

[0155] (61) The second coronary curvature intersects the sagittal concave curvature of the medial articular surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the medial articular surface. The second coronary curvature is defined by a planar portion having an inner end and an outer end, a first coronary curved portion extending from the inner end of the planar portion, and a second coronary curved portion extending from the outer end of the planar portion. The tibial insert according to Embodiment 59. (62) The tibial insert according to Embodiment 61, wherein a radius of curvature of the first coronal curvature portion of the second coronal curvature is smaller than a radius of curvature of the second coronal curvature portion of the second coronal curvature. (63) The tibial insert according to Embodiment 62, wherein the first coronal curvature of the second coronal curvature portion extends over an arc length in a range of 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length in a range of 20.1 degrees to 28.5 degrees. (64) The third coronal curvature intersects the sagittal concave curvature of the medial articular surface at a foremost point of the fourth curvature portion among the plurality of curvature portions defining the sagittal concave curvature of the medial articular surface. The third coronal curvature is defined by a planar portion having a medial end and a lateral end, a first coronal curvature portion extending from the medial end of the planar portion, and a second coronal curvature portion extending from the lateral end of the planar portion. The tibial insert according to Embodiment 61. (65) The tibial insert according to Embodiment 64, wherein the planar portion of the third coronal curvature forms an angle of about 6 degrees with a bottom surface of the tibial insert.

[0156] (66) The tibial insert according to Embodiment 65, wherein the first coronal curvature portion of the third coronal curvature extends over an arc length in a range of 0.3 degrees to 0.9 degrees, and the second coronal curvature portion of the third coronal curvature extends over an arc length in a range of 24.6 degrees to 16.5 degrees. (67) Further including a front side and a rear side opposite to the front side, a distance between the front side and the rear side defines an anteroposterior length of the tibial insert. The medial doell point is located at a position of about 63.3% of the anteroposterior length from the front end. The tibial insert according to Embodiment 24. (68) The arcuate joint path of the lateral articular surface is defined by a radius of curvature having an origin on the medial doell point when viewed in a horizontal plane. The tibial insert according to Embodiment 24. (69) Further comprising a first portion of a locking mechanism located on the bottom surface of the tibial insert, the first portion of the locking mechanism being configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base, the tibial insert according to embodiment 24. (70) An orthopedic knee prosthesis, A femoral component having a lateral condyle and a medial condyle, the medial condyle including a femoral articular surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion defined by a continuously decreasing radius of curvature, a femoral component, and A tibial insert having an outer articular surface configured to articulate with the lateral condyle of the femoral component and an inner articular surface configured to articulate with the medial condyle of the femoral component, the inner articular surface being shaped asymmetrically with respect to the outer articular surface and including an inner dovetail point defining the most distal point on the inner articular surface, a tibial insert, comprising: The medial condyle contacts the inner dovetail point at a first contact point on the first curved femoral surface portion at a first flexion angle and contacts the inner dovetail point at a second contact point on the first curved femoral surface portion at a second flexion angle, the second contact point being behind the first contact point, and the second flexion angle being greater than the first flexion angle, The inner articular surface includes a sagittal concave curvature having a first sagittal conformity with the medial condyle at a position in front of the dovetail point at the first flexion angle and a second sagittal conformity with the medial condyle at the position in front of the dovetail point at the second flexion angle, the second sagittal conformity being greater than the first sagittal conformity and reducing the forward translation of the medial condyle at the second flexion angle, an orthopedic knee prosthesis.

[0157] (71) The medial condyle of the femoral component includes a sagittal convex curvature, and the sagittal conformity between the sagittal concave curvature of the inner articular surface and the sagittal concave curvature of the medial condyle is greater at the first flexion angle of the femoral condyle than at extension, the orthopedic knee prosthesis according to embodiment 70. (72) The orthopedic knee prosthesis according to embodiment 71, wherein the first flexion degree is about 30 degrees. (73) The orthopedic knee prosthesis according to embodiment 70, wherein the medial articular surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle at the flexion degree is greater at the medial condyle point of the medial articular surface than at the position on the medial articular surface in front of the medial doell point. (74) The orthopedic knee prosthesis according to embodiment 73, wherein the medial articular surface is non-uniform in front of the medial doell point and uniform behind the medial doell point. (75) The orthopedic knee prosthesis according to embodiment 70, wherein the medial condyle and the medial articular surface are more compatible with each other than the lateral condyle and the lateral articular surface.

[0158] (76) The orthopedic knee prosthesis according to embodiment 70, wherein the medial articular surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the medial condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a subsequent flexion degree. (77) The lateral articular surface includes an arcuate joint path having a curvature including a planar portion, a forwardly curved portion located in front of the quasi-planar portion, and a plurality of rearwardly curved portions located behind the planar portion when viewed in cross-section. The orthopedic knee prosthesis according to embodiment 70, wherein the quasi-planar portion defines the most distal region of the lateral articular surface. (78) Each of the rearwardly curved portions is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly. The orthopedic knee prosthesis according to embodiment 77. (79) The sagittal concave curvature of the medial articular surface includes a plurality of curved portions when viewed in the sagittal plane, and the medial doell point is located on the sagittal concave curvature. The plurality of curved portions include a first curved portion that is adjacent to the inner door point and extends rearward therefrom, a second curved portion that is adjacent to the inner door point and extends forward therefrom, a third curved portion that is adjacent to the second curved portion and extends forward therefrom, a fourth curved portion that is adjacent to the third curved portion and extends forward therefrom, and a fifth curved portion that is adjacent to the fourth curved portion and extends forward therefrom. The radius of curvature of the first curved portion is larger than the radius of curvature of the second curved portion, and the radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth radius of curvature. The orthopedic knee prosthesis according to Embodiment 70. (80) The inner joint surface includes a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the inner door point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature. The inner joint surface includes a coronal concave curvature defined by a plurality of coronal curvatures, and each of the first coronal curvature, the second coronal curvature, and the third coronal curvature is different from each other. The orthopedic knee prosthesis according to Embodiment 79.

[0159] (81) The second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The second coronal curvature is defined by a flat portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the flat portion, and a second coronal curved portion extending from the outer end of the flat portion. The radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion. The orthopedic knee prosthesis according to Embodiment 80. (82) The third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface, and the third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. The orthopedic knee prosthesis according to embodiment 81. (83) The tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert, and the first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base. The orthopedic knee prosthesis according to embodiment 70. (84) The farthest point on the femoral joint surface when the femoral component is in the extended state defines 0 degrees of flexion. The first curved femoral surface portion extends from about 5 degrees of the first flexion degree to about 65 degrees of the second flexion degree. The orthopedic knee prosthesis according to embodiment 70. (85) The first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion, and each line has a length defined by the following polynomial. r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 )) wherein r θ is the length of the line defining the point on the second curved femoral surface portion at θ degrees of flexion, a is a coefficient value of 20 to 50, b is a coefficient value in a range selected from the group consisting of -0.30 < b < 0.00, 0.00 < b < 0.30, and b = 0. When b is in the range of -0.30 < b < 0.00, (i) c is a coefficient value of 0.00 to 0.012, and (ii) d is a coefficient value of -0.00015 to 0.00. When b is in the range of 0 < b < 0.30, (i) c is a coefficient value in the range of -0.010 to 0.00, and (ii) d is a coefficient value in the range of -0.00015 to 0.00. The orthopedic knee prosthesis according to Embodiment 84, wherein when b is equal to 0, (i) c is a coefficient value in the range selected from the group consisting of -0.0020 < c < 0.00 and 0.00 < c < 0.0025, and (ii) d is a coefficient value in the range of -0.00015 to 0.00.

[0160] (86) The plurality of curved femoral surface portions include a second curved femoral surface portion adjacent to the rear of the first curved femoral portion, and the second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature at the rearmost of the first curved femoral surface portion. The orthopedic knee prosthesis according to Embodiment 85. (87) The second curved femoral surface portion extends from a first flexion angle of about 65 degrees to a second flexion angle of about 90 degrees. The orthopedic knee prosthesis according to Embodiment 86. (88) An orthopedic knee prosthesis, A femoral component having a lateral condyle and a medial condyle, the medial condyle including a femoral articular surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion and a second curved femoral surface portion adjacent to the rear of the first curved femoral surface portion, the first curved femoral surface portion being defined by a continuously decreasing radius of curvature, and the second curved femoral surface portion being defined by a constant radius of curvature greater than the radius of curvature at the rearmost of the first curved femoral surface portion, a femoral component; A tibial insert having an outer articular surface configured to articulate with the lateral condyle of the femoral component and an inner articular surface configured to articulate with the medial condyle of the femoral component, the inner articular surface being asymmetrically shaped with respect to the outer articular surface and including an inner dome point defining the most distal point on the inner articular surface, a tibial insert, comprising: The inner condyle contacts the inner trochlear point at a first contact point on the first curved femoral surface portion at a first flexion angle, the first contact point being defined by the rearmost radius of curvature of the first curved femoral surface portion, and (ii) contacts the inner trochlear point at a second contact point on the second curved femoral surface portion at a second flexion angle greater than the first flexion angle, the second contact point being defined by the constant radius of curvature of the second curved femoral surface portion. An orthopedic knee prosthesis, wherein a vertical distance between the inner trochlear point at the second flexion angle and an origin of the constant radius of curvature of the second curved femoral surface portion is greater than a vertical distance between the inner trochlear point at the first flexion angle and an origin of the rearmost radius of curvature of the first curved femoral surface portion. (89) The inner condyle of the femoral component includes a sagittal convex curvature, the inner joint surface includes a sagittal concave curvature, and a sagittal conformity between the sagittal concave curvature of the inner joint surface and the sagittal concave curvature of the inner condyle is greater at a first flexion angle of the femoral condyle than in extension, the orthopedic knee prosthesis according to embodiment 88. (90) The orthopedic knee prosthesis according to embodiment 89, wherein the first flexion angle is about 30 degrees.

[0161] (91) The inner joint surface includes a sagittal concave curvature, and at the inner trochlear point, the sagittal concave curvature has a first sagittal conformity with the inner condyle at the first flexion angle of the femoral component, and at a position on the inner joint surface in front of the inner trochlear point, the sagittal concave curvature has a second sagittal conformity with the inner condyle at the first flexion angle, the second sagittal conformity being greater than the first sagittal conformity, the orthopedic knee prosthesis according to embodiment 88. (92) The inner joint surface includes a coronal concave curvature. At the inner trochlear point, the coronal concave curvature has a first coronal conformity with the inner condyle at the first flexion degree. At the position on the inner joint surface in front of the inner trochlear point, the coronal concave curvature has a second coronal conformity with the inner condyle at the first flexion degree, and the second coronal conformity is greater than the first coronal conformity. The orthopedic knee prosthesis according to Embodiment 91. (93) The inner joint surface is non-uniform in front of the inner trochlear point and uniform behind the inner trochlear point. The orthopedic knee prosthesis according to Embodiment 92. (94) The inner condyle and the inner joint surface are more conformable to each other than the outer condyle and the outer joint surface. The orthopedic knee prosthesis according to Embodiment 88. (95) The inner joint surface includes a coronal concave curvature. The coronal conformity between the coronal concave curvature and the inner condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a later flexion degree. The orthopedic knee prosthesis according to Embodiment 88.

[0162] (96) The outer joint surface includes an arcuate joint path having a curvature that includes a quasi-planar portion, a forwardly curved portion located in front of the quasi-planar portion, and a plurality of rearwardly curved portions located behind the planar portion when viewed in cross-section. The planar portion defines the most distal region of the outer joint surface. The orthopedic knee prosthesis according to Embodiment 88. (97) Each rearwardly curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rearwardly curved portions decrease rearwardly. The orthopedic knee prosthesis according to Embodiment 96. (98) The sagittal concave curvature of the inner joint surface includes a plurality of curved portions when viewed in the sagittal plane, and the inner trochlear point is located on the sagittal concave curvature. The plurality of curved portions include a first curved portion that is adjacent to the inner condyle point and extends rearward therefrom, a second curved portion that is adjacent to the inner condyle point and extends forward therefrom, a third curved portion that is adjacent to the second curved portion and extends forward therefrom, a fourth curved portion that is adjacent to the third curved portion and extends forward therefrom, and a fifth curved portion that is adjacent to the fourth curved portion and extends forward therefrom. The orthopedic knee prosthesis according to Embodiment 88, wherein a radius of curvature of the first curved portion is larger than a radius of curvature of the second curved portion, and a radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion, smaller than a radius of curvature of the fourth curved portion, and smaller than a radius of curvature of the fifth curved portion. (99) The inner joint surface includes a coronary concave curvature defined by a plurality of coronary curvatures, including a first coronary curvature that intersects the sagittal concave curvature of the inner joint surface at the inner condyle point, a second coronary curvature located in front of the first coronary curvature, and a third coronary curvature located in front of the second coronary curvature, and each of the first coronary curvature, the second coronary curvature, and the third coronary curvature is different from each other. The orthopedic knee prosthesis according to Embodiment 98. (100) The second coronary curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The second coronary curvature is defined by a flat portion having an inner end and an outer end, a first coronary curved portion extending from the inner end of the flat portion, and a second coronary curved portion extending from the outer end of the flat portion. A radius of curvature of the first coronary curved portion is smaller than a radius of curvature of the second coronary curved portion. The orthopedic knee prosthesis according to Embodiment 99.

[0163] (101) The third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. The orthopedic knee prosthesis according to Embodiment 100. (102) The tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to engage with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base. The orthopedic knee prosthesis according to Embodiment 88. (103) The farthest point of the femoral joint surface when the femoral component is in the extended state defines 0 degrees of flexion. The first curved femoral surface portion extends from about 5 degrees of the first flexion degree to about 65 degrees of the second flexion degree. The orthopedic knee prosthesis according to Embodiment 88. (104) The first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion. Each line has a length defined by the following polynomial. r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 )) wherein r θ is the length of the line defining the point on the second curved femoral surface portion at θ degrees of flexion, a is a coefficient value between 20 and 50, and b is a coefficient value in the range selected from the group consisting of -0.30 < b < 0.00, 0.00 < b < 0.30, and b = 0. When b is in the range of -0.30 < b < 0.00, (i) c is a coefficient value between 0.00 and 0.012, and (ii) d is a coefficient value between -0.00015 and 0.00. When b is in the range of 0 < b < 0.30, (i) c is a coefficient value in the range of -0.010 to 0.00, and (ii) d is a coefficient value in the range of -0.00015 to 0.00. When b is equal to 0, (i) c is a coefficient value in a range selected from the group consisting of -0.0020 < c < 0.00 and 0.00 < c < 0.0025, and (ii) d is a coefficient value in the range of -0.00015 to 0.00. The orthopedic knee prosthesis according to Embodiment 103. (105) The plurality of curved femoral surface portions include a second curved femoral surface portion adjacent to the rear of the first curved femoral portion. The second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature of the rearmost portion of the first curved femoral surface portion. The orthopedic knee prosthesis according to Embodiment 104.

[0164] (106) The second curved femoral surface portion extends from a first flexion angle of about 65 degrees to a second flexion angle of about 90 degrees. The orthopedic knee prosthesis according to Embodiment 105. (107) An orthopedic knee prosthesis, A femoral component having a lateral condyle and a medial condyle, the medial condyle including a femoral joint surface defined by a plurality of curved femoral surface portions including a first curved femoral surface portion defined by a continuously decreasing radius of curvature, a femoral component; A tibial insert having an outer joint surface configured to articulate with the lateral condyle of the femoral component and an inner joint surface configured to articulate with the medial condyle of the femoral component, The outer joint surface includes an arcuate joint path extending in the anteroposterior direction. The arcuate joint path has a curvature including a planar portion when viewed in cross-section. The planar portion defines the most distal region of the outer joint surface. The inner articular surface is shaped asymmetrically with respect to the outer articular surface and includes an inner dome point that defines the most distal point of the inner dome surface. The inner dome point is on the inner dome surface and is (i) between a first virtual medial-lateral bisector of the tibial insert that includes the foremost end of the planar portion of the sagittal curvature of the outer articular surface and a second virtual medial-lateral bisector of the tibial insert that includes the rearmost end of the planar portion of the sagittal curvature of the outer articular surface, and (ii) located posterior to the midpoint between the front and rear of the planar portion of the sagittal curvature of the outer articular surface, and comprises a tibial insert. An orthopedic knee prosthesis. (108) The medial condyle of the femur component includes a sagittal convex curvature, the inner articular surface includes a sagittal concave curvature, and the sagittal conformity between the sagittal concave curvature of the inner articular surface and the sagittal concave curvature of the medial condyle is greater at a first flexion angle of the femoral condyle than at extension. The orthopedic knee prosthesis according to embodiment 107. (109) The orthopedic knee prosthesis according to embodiment 108, wherein the first flexion angle is about 30 degrees. (110) The inner articular surface includes a sagittal concave curvature. At the inner dome point, the sagittal concave curvature has a first sagittal conformity with the inner condyle at the first flexion angle of the femur component. At a position on the inner articular surface in front of the inner dome point, the sagittal concave curvature has a second sagittal conformity with the inner condyle at the first flexion angle, and the second sagittal conformity is greater than the first sagittal conformity. The orthopedic knee prosthesis according to embodiment 107.

[0165] (111) The inner articular surface includes a coronal concave curvature. At the inner dome point, the coronal concave curvature has a first coronal conformity with the inner condyle at the first flexion angle. At the position on the inner articular surface in front of the inner dome point, the coronal concave curvature has a second coronal conformity with the inner condyle at the first flexion angle, and the second coronal conformity is greater than the first coronal conformity. The orthopedic knee prosthesis according to embodiment 110. (112) The orthopaedic knee prosthesis according to embodiment 111, wherein the inner joint surface is non-uniform in front of the inner door point and uniform behind the inner door point. (113) The orthopaedic knee prosthesis according to embodiment 107, wherein the inner joint surface includes a coronal concave curvature, and the coronal conformity between the coronal concave curvature and the inner condyle is greater when the femoral component is disposed in extension than when the femoral component is disposed at a later degree of flexion. (114) The arcuate joint path of the outer joint surface has a curvature including a quasi-planar portion, a front curved portion located in front of the planar portion, and a plurality of rear curved portions located behind the planar portion when viewed in cross-section. The orthopaedic knee prosthesis according to embodiment 107, wherein the quasi-planar portion defines the most distal region of the outer joint surface. (115) Each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the plurality of rear curved portions decrease rearward. The orthopaedic knee prosthesis according to embodiment 114.

[0166] (116) The sagittal concave curvature of the inner joint surface includes a plurality of curved portions when viewed in the sagittal plane, and the inner door point is located on the sagittal concave curvature. The plurality of curved portions include a first curved portion adjacent to and extending rearward from the inner door point, a second curved portion adjacent to and extending forward from the inner door point, a third curved portion adjacent to the second curved portion and extending forward therefrom, a fourth curved portion adjacent to the third curved portion and extending forward therefrom, and a fifth curved portion adjacent to the fourth curved portion and extending forward therefrom. The radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion, the radius of curvature of the third curved portion is smaller than the radius of curvature of the second curved portion and smaller than the radius of curvature of the fourth curved portion, and smaller than the radius of the fifth radius of curvature. The orthopaedic knee prosthesis according to embodiment 107. (117) The inner joint surface includes a coronal concave curvature defined by a plurality of coronal curvatures, including a first coronal curvature that intersects the sagittal concave curvature of the inner joint surface at the inner door point, a second coronal curvature located in front of the first coronal curvature, and a third coronal curvature located in front of the second coronal curvature, and each of the first coronal curvature, the second coronal curvature, and the third coronal curvature is different from each other. The orthopedic knee prosthesis according to Embodiment 116. (118) The second coronal curvature intersects the sagittal concave curvature of the inner joint surface at the last point of the third curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The second coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. The radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion. The orthopedic knee prosthesis according to Embodiment 117. (119) The third coronal curvature intersects the sagittal concave curvature of the inner joint surface at the foremost point of the fourth curved portion among the plurality of curved portions that define the sagittal concave curvature of the inner joint surface. The third coronal curvature is defined by a planar portion having an inner end and an outer end, a first coronal curved portion extending from the inner end of the planar portion, and a second coronal curved portion extending from the outer end of the planar portion. The orthopedic knee prosthesis according to Embodiment 118. (120) The tibial insert further includes a first portion of a locking mechanism located on the bottom surface of the tibial insert. The first portion of the locking mechanism is configured to fit with a second portion of the locking mechanism located on the tibial base to fix the tibial insert to the tibial base. The orthopedic knee prosthesis according to Embodiment 107.

[0167] (121) The most distal point of the femoral joint surface when the femoral component is in the extended state defines 0 degrees of flexion. The orthopedic knee prosthesis according to Embodiment 107, wherein the first curved femoral surface portion extends from a first flexion angle of about 5 degrees to a second flexion angle of about 65 degrees. (122) The first curved femoral surface portion is defined by a plurality of lines extending from a common origin to corresponding points on the second curved femoral surface portion, and each line has a length defined by the following polynomial: r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 )) wherein r θ is the length of the line defining the point on the second curved femoral surface portion at a flexion of θ degrees, a is a coefficient value of 20 to 50, and b is -0.30 <b<0.00、0.00<b<0.30、及びb=0からなる群から選択される範囲の係数値であり、b is -0.30 <b<0.00の範囲にあるとき、(i)cは0.00~0.012の係数値であり、(ii)dは-0.00015~0.00の係数値であり、b is 0 <b<0.30の範囲にあるとき、(i)cは-0.010~0.00の係数値であり、(ii)dは-0.00015~0.00の係数値であり、When b is equal to 0, (i) c is -0.0020 <c<0.00及び0.00<c<0.0025からなる群から選択される範囲の係数値であり、(ii)dは-0.00015~0.00の係数値である、実施態様121に記載の整形外科用膝プロテーゼ。(123) The plurality of curved femoral surface portions includes a second curved femoral surface portion adjacent to the rear of the first curved femoral surface portion, and the second curved femoral surface portion is defined by a constant radius of curvature greater than the radius of curvature of the rearmost portion of the first curved femoral surface portion. The orthopedic knee prosthesis according to Embodiment 122. (124) The second curved femoral surface portion extends from a first flexion angle of about 65 degrees to a second flexion angle of about 90 degrees. The orthopedic knee prosthesis according to Embodiment 123.

Claims

1. A tibial insert, configured to articulate with the lateral condyle of the femoral component and including a lateral articular surface having an arcuate articular path extending in the anteroposterior direction, the arcuate articular path being defined by a plurality of points on the lateral articular surface, each point defining the most distal point of the lateral articular surface in the corresponding medial and lateral cross-sections when the tibial insert is viewed in the medial and lateral cross-sections at each point, the lateral articular surface having a cross-sectional concave curvature orthogonal to the arcuate articular path, the radius of curvature of the cross-sectional concave curvature being constant at each of the plurality of points and the curved portion being single, the lateral articular surface, and an inner articular surface configured to articulate with the medial condyle of the femoral component, the inner articular surface being shaped asymmetrically with respect to the outer articular surface and having a coronal concave curvature having a non-constant radius of curvature in the anteroposterior direction, the inner articular surface, comprising, the arcuate articular path having a curvature including a quasi-planar portion, a forwardly curved portion located in front of the quasi-planar portion, and a plurality of rearwardly curved portions located behind the quasi-planar portion when viewed in cross-section, the tibial insert, wherein the quasi-planar portion defines a lateral dovetail region that defines the most distal region of the lateral articular surface.

2. The inner articular surface includes an inner dovetail point that defines the most distal point of the inner articular surface, the radius of curvature of the coronal concave curvature of the inner articular surface being non-constant in front of the inner dovetail point and constant behind the inner dovetail point, the tibial insert according to claim 1.

3. Each of the rearwardly curved portions is defined by a corresponding radius of curvature, the radius of curvature of the plurality of rearwardly curved portions decreasing rearwardly, the tibial insert according to claim 1.

4. The plurality of rearwardly curved portions includes a first rearwardly curved portion adjacent to the rearmost end of the quasi-planar portion and a second rearwardly curved portion adjacent to the first rearwardly curved portion, the radius of curvature of the first rearwardly curved portion being larger than the radius of curvature of the second rearwardly curved portion, the tibial insert according to claim 1. **Claim 5**: The anterior curved portion is defined by a corresponding radius of curvature that is (i) smaller than the radius of curvature of the first posterior curved portion and (ii) larger than the radius of curvature of the second posterior curved portion, of the tibial insert according to claim 4. **Claim 6** A tibial insert comprising: An outer joint surface configured to articulate with the lateral condyle of the femoral component and including an arcuate joint path extending in the anteroposterior direction, the arcuate joint path being defined by a plurality of points on the outer joint surface, and when the tibial insert is viewed in the medial-lateral cross-section at each point, each point defines the most distal point of the outer joint surface in the corresponding medial-lateral cross-section, the outer joint surface having a cross-sectional concave curvature orthogonal to the arcuate joint path, the radius of curvature of the cross-sectional concave curvature being constant at each of the plurality of points and the curved portion being single, an outer joint surface; An inner joint surface configured to articulate with the medial condyle of the femoral component, the inner joint surface being shaped asymmetrically with respect to the outer joint surface and having a coronal concave curvature with a non-constant radius of curvature in the anteroposterior direction, an inner joint surface; and The inner joint surface, when viewed in the sagittal plane, includes a sagittal concave curvature defined by a plurality of curved portions and an inner dome point that defines the most distal point of the inner joint surface, the inner dome point being located on the sagittal concave curvature; The plurality of curved portions include a first curved portion adjacent to and extending rearward from the inner dome point and a second curved portion adjacent to and extending forward from the inner dome point, the radius of curvature of the first curved portion being larger than the radius of curvature of the second curved portion, a tibial insert.

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