Medial stabilized orthopedic knee prosthesis

Abstract

To provide orthopedic knee prosthesis, instrumentation and methods for total knee arthroplasty.SOLUTION: An orthopedic 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 a medial condyle of the femoral component, while the lateral articular surface is shaped to allow a lateral condyle of the femoral component to pivot, relative to the medial articular surface, along an arcuate articular path. Additionally, one or both condyles (112, 114) of the femoral component may include a femoral articular surface (110) having a curved femoral surface section defined by a continuously decreasing radius of curvature.SELECTED DRAWING: Figure 1

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, entitled "ORTHOPAEDIC KNEE PROSTHESIS SYSTEM AND METHODS FOR USING SAME," filed July 10, 2020, which is expressly incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present disclosure relates to orthopaedic knee prosthesis systems, and more particularly to orthopaedic knee prostheses, instruments, and methods for total knee arthroplasty. [Background technology]

[0003] Arthroplasty is a well-known surgical procedure in which a diseased and / or damaged natural joint is replaced with an artificial joint. A typical knee prosthesis includes a tibial tray, a femoral component, and a polymer 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 mobile orthopedic 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 motion of the knee prosthesis, such as when significant soft tissue damage or loss is present. Alternatively, a knee prosthesis may include a "mobile" tibial insert in cases where greater freedom of movement is desired. In addition, a knee prosthesis may be an artificial knee prosthesis designed to replace the femoral-tibial interface of both condyles of the patient's femur, or a unicompartmental knee prosthesis designed to replace the femoral-tibial interface of a single condyle of the patient's femur.

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

[0005] A typical orthopedic knee prosthesis is generally designed to replicate the natural motion of a patient's joint. As the knee flexes and extends, the femoral and tibial components articulate and undergo a combination of relative anterior-posterior motion and relative internal-external rotation. However, the patient's surrounding soft tissue also influences the kinematics and stability of the orthopedic knee prosthesis throughout the joint's range of motion. That is, forces exerted on the orthopedic components by the patient's soft tissue can cause unwanted or undesirable motion of the orthopedic knee prosthesis. For example, an orthopedic knee prosthesis may exhibit unnatural (paradoxical) anterior 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 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 anterior-posterior direction. The arcuate articular path is defined by a plurality of points on the lateral articular surface, and when the tibial insert is viewed in a medial-lateral cross section at each point, each point defines a distal-most point of the lateral articular surface in the corresponding medial-lateral cross section. The lateral articular surface has a cross-sectional concave curvature perpendicular to the arcuate articular path, and the cross-sectional concave curvature is uniform at each of the plurality of points. The medial articular surface is configured to articulate with the medial condyle of the femoral component. The medial articular surface is asymmetrically shaped relative to the lateral articular surface and has a non-uniform coronal concave curvature in the anterior-posterior direction.

[0007] In one embodiment, the medial articular surface includes a medial dwell point defining the distal-most point of the medial articular surface, the coronal concave curvature of the medial articular surface being non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0008] In one embodiment, the arcuate joint path has a curvature when viewed in cross section that includes a semi-planar portion, a front curved portion located anterior to the planar portion, and multiple rear curved portions located posterior to the planar portion. The semi-planar portion defines a lateral dwell region that defines the distal-most region of the lateral articular surface. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple rear curved portions decrease posteriorly.

[0009] In one embodiment, the plurality of back curved portions includes a first back curved portion adjacent the rearmost end of the planar portion and a second back curved portion adjacent the first back curved portion, the first back curved portion having a larger radius of curvature than the second back curved portion. In one embodiment, the front curved portions are defined by corresponding radii of curvature that are (i) smaller than the radius of curvature of the first back curved portion and (ii) larger than the radius of curvature of the second back curved portion. In one embodiment, the front curved portions extend over an arc length ranging from 33.5 degrees to 34.4 degrees, the first back curved portion extends over approximately 3.4 degrees, and the second back curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees.

[0010] In one embodiment, the medial articular surface, when viewed in the sagittal plane, includes a sagittal concave curvature defined by a plurality of curved segments and a medial dwell point defining a distal-most point of the medial articular surface, the medial dwell point being located on the sagittal concave curvature. In one embodiment, the plurality of curved segments includes a first curved segment adjacent to and extending posteriorly from the medial dwell point and a second curved segment adjacent to and extending anteriorly from the medial dwell point, the first curved segment having a greater radius of curvature than the second curved segment. In one embodiment, the first curved segment extends over an arc length ranging from 15.9 degrees to 17.4 degrees, and the second curved segment extends over approximately 5.2 degrees.

[0011] In one embodiment, the plurality of curved portions includes 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 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 ranging from 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length ranging from 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length ranging from 0.2 degrees to 6.3 degrees.

[0012] In one embodiment, the coronal concave curvature of the medial articular surface is defined by a plurality of coronal curves, including a first coronal curve that intersects the sagittal concave curvature of the medial articular surface at a medial dwell point, a second coronal curve that is anterior to the first coronal curve, and a third coronal curve that is anterior to the second coronal curve, each of the first, second, and third coronal curves being different from one another. In one embodiment, the first coronal curve is defined by a coronal curve portion that extends from the medial dwell point over an arc length ranging from 18.6 degrees to 26.8 degrees medially and from the medial dwell point over approximately 25.0 degrees laterally. In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second 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. 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 ranging from 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length ranging from 20.1 degrees to 28.5 degrees.

[0013] In one embodiment, the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface. The third coronal curve 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 curve forms an angle of approximately 6 degrees with respect to the bottom surface of the tibial insert. In one embodiment, the first coronal curved portion of the third coronal curve extends over an arc length ranging from 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curve extends over an arc length ranging from 16.4 degrees to 24.7 degrees.

[0014] In one embodiment, the tibial insert further includes an anterior sidewall and a posterior sidewall opposite the anterior side, the distance between the anterior sidewall and the posterior sidewall defining an anterior-posterior length of the tibial insert. The medial articular surface includes a medial dwell point defining a distal-most point of the medial articular surface, the medial dwell point being located approximately 63.3% of the anterior-posterior length from the anterior end.

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

[0016] In one embodiment, the tibial insert further includes a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism configured to mate with a second portion of the locking mechanism located on the tibial base to secure 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 anterior-posterior direction. When viewed in cross section, the arcuate articular path has a curvature that includes a semi-planar portion, the semi-planar portion defining the distal-most 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 asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point that defines the distal-most point of the medial condylar surface. The medial dwell point is located on the medial condylar surface (i) between a first imaginary medial-lateral bisector of the tibial insert that includes the anterior-most end of the planar portion of the sagittal curvature of the lateral articular surface and a second imaginary medial-lateral bisector of the tibial insert that includes the posterior-most end of the planar portion of the sagittal curvature of the lateral articular surface, and (ii) posterior to the anterior-posterior midpoint of the planar portion of the sagittal curvature of the lateral articular surface.

[0018] In one embodiment, the tibial insert further includes an anterior sidewall and a posterior sidewall opposite the anterior sidewall, the distance between the anterior sidewall and the posterior sidewall defining an anterior-posterior length of the tibial insert, and the medial dwell point is located approximately 63.3% of the anterior-posterior length from the anterior end.

[0019] In one embodiment, the medial articular surface has a coronal concave curvature that is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0020] In one embodiment, the curvature of the arcuate joint path, when viewed in cross section, further includes a forward curved portion located anterior to the semi-planar portion and multiple backward curved portions located posterior to the semi-planar portion. In one embodiment, each backward curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple backward curved portions decrease posteriorly. In one embodiment, the multiple backward curved portions include a first backward curved portion adjacent the posterior end of the planar portion and a second backward curved portion adjacent to the first backward curved portion, and the radius of curvature of the first backward curved portion is greater than the radius of curvature of the second backward curved portion. In one embodiment, the forward curved portions are defined by corresponding radii of curvature that are (i) smaller than the radius of curvature of the first backward curved portion and (ii) greater than the radius of curvature of the second backward curved portion. In one embodiment, the forward curved portion extends over an arc length ranging from 33.5 degrees to 34.4 degrees, the first back curved portion extends over approximately 3.4 degrees, and the second back curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees.

[0021] In one embodiment, the medial articular surface, when viewed in the sagittal plane, includes a sagittal concave curvature defined by a plurality of curved segments, and the medial dwell point is located on the sagittal concave curvature. In one embodiment, the plurality of curved segments includes a first curved segment adjacent to and extending posteriorly from the medial dwell point and a second curved segment adjacent to and extending anteriorly from the medial dwell point, the first curved segment having a greater radius of curvature than the second curved segment. In one embodiment, the first curved segment extends over an arc length ranging from 15.9 degrees to 17.4 degrees, and the second curved segment extends over approximately 5.2 degrees.

[0022] In one embodiment, the plurality of curved portions include 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, wherein 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 ranging from 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length ranging from 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length ranging from 0.2 degrees to 6.3 degrees.

[0023] In one embodiment, the medial articular surface has a coronal curvature defined by a plurality of coronal curves, including a first coronal curve intersecting the sagittal concave curvature of the medial articular surface at a medial dwell point, a second coronal curve located anterior to the first coronal curve, and a third coronal curve located anterior to the second coronal curve, each of the first, second, and third coronal curves being different from one another. In one embodiment, the first coronal curve is defined by a coronal curve portion extending medially from the medial dwell point over an arc length ranging from 18.6 degrees to 26.8 degrees and laterally from the medial dwell point over approximately 25.0 degrees.

[0024] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second 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. 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 ranging from 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length ranging from 20.1 degrees to 28.5 degrees.

[0025] In one embodiment, the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve 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 curve forms an angle of approximately 6 degrees with respect to the bottom surface of the tibial insert. In one embodiment, the first coronal curved portion of the third coronal curve extends over an arc length ranging from 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curve extends over an arc length ranging from 16.4 degrees to 24.7 degrees.

[0026] In one embodiment, the arcuate joint path is defined by a radius of curvature that has its origin on the medial dwell 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 a bottom surface of the tibial insert, the first portion of the locking mechanism configured to mate with a second portion of the locking mechanism located on the tibial base to secure the tibial insert to the tibial base.

[0028] According to another aspect, the tibial insert includes 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 lateral articular surface includes an arcuate articular path extending in the anterior-posterior direction, a lateral dwell point defining a distal-most point on the lateral articular surface located on the arcuate articular path, and an anterior-lateral lip, wherein the superior-inferior distance between the lateral dwell point and a top point of the anterior-lateral lip defines a lip height of the anterior-lateral lip. The medial articular surface is asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point defining a distal-most point on the medial articular surface and an anterior-medial lip, wherein the superior-inferior distance between the medial dwell point and a top point of the medial-lateral lip defines a 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 anterior-posterior distance between the anterior sidewall of the medial articular surface and the posterior sidewall of the medial articular surface ranges from 18.9% to 20.9%.

[0029] In one embodiment, the medial articular surface has a coronal concave curvature that is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0030] In one embodiment, the arcuate joint path has a curvature when viewed in cross section that includes a semi-planar portion, a forward curved portion located anterior to the planar portion, and multiple rearward curved portions located posterior to the planar portion, and the outer dwell point is located in the semi-planar portion.

[0031] In one embodiment, 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.

[0032] In one embodiment, the plurality of back curved portions includes a first back curved portion adjacent the rearmost end of the planar portion and a second back curved portion adjacent the first back curved portion, the first back curved portion having a larger radius of curvature than the second back curved portion. In one embodiment, the front curved portions are defined by corresponding radii of curvature that are (i) smaller than the radius of curvature of the first back curved portion and (ii) larger than the radius of curvature of the second back curved portion. In one embodiment, the front curved portions extend over an arc length ranging from 33.5 degrees to 34.4 degrees, the first back curved portion extends over approximately 3.4 degrees, and the second back curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees.

[0033] In one embodiment, the medial articular surface, when viewed in the sagittal plane, includes a sagittal concave curvature defined by a plurality of curved segments, and the medial dwell point is located on the sagittal concave curvature. In one embodiment, the plurality of curved segments includes a first curved segment adjacent to and extending posteriorly from the medial dwell point and a second curved segment adjacent to and extending anteriorly from the medial dwell point, the first curved segment having a greater radius of curvature than the second curved segment. In one embodiment, the first curved segment extends over an arc length ranging from 15.9 degrees to 17.4 degrees, and the second curved segment extends over approximately 5.2 degrees.

[0034] In one embodiment, the plurality of curved portions include 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, wherein 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 ranging from 14.8 degrees to 24.8 degrees, the fourth curved portion extends over an arc length ranging from 10.7 degrees to 20.7 degrees, and the fifth radius of curvature extends over an arc length ranging from 0.2 degrees to 6.3 degrees.

[0035] In one embodiment, the medial articular surface has a coronal curvature defined by a plurality of coronal curves, including a first coronal curve intersecting the sagittal concave curvature of the medial articular surface at a medial dwell point, a second coronal curve located anterior to the first coronal curve, and a third coronal curve located anterior to the second coronal curve, each of the first, second, and third coronal curves being different from one another. In one embodiment, the first coronal curve is defined by a coronal curve portion extending medially from the medial dwell point over an arc length ranging from 18.6 degrees to 26.8 degrees and laterally from the medial dwell point over approximately 25.0 degrees.

[0036] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second 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. 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 ranging from 14.7 degrees to 15.7 degrees, and the second coronal curvature portion of the second coronal curvature extends over an arc length ranging from 20.1 degrees to 28.5 degrees.

[0037] In one embodiment, the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve 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 curve forms an angle of approximately 6 degrees with respect to the bottom surface of the tibial insert. In one embodiment, the first coronal curved portion of the third coronal curve extends over an arc length ranging from 0.3 degrees to 0.9 degrees, and the second coronal curved portion of the third coronal curve extends over an arc length ranging from 16.4 degrees to 24.7 degrees.

[0038] In one embodiment, the tibial insert further includes an anterior side and a posterior side opposite the anterior side. The distance between the anterior side and the posterior side defines an anterior-posterior length of the tibial insert. The medial dwell point is located approximately 63.3% of the anterior-posterior length from the anterior end. In one embodiment, the arcuate articular path of the lateral articular surface, when viewed in a horizontal plane, is defined by a radius of curvature having an origin at the medial dwell point.

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

[0040] According to yet another aspect, an orthopaedic 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 asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point defining a distal-most point on the medial articular surface. The medial condyle contacts the medial dwell point at a first contact point on the first curved femoral surface portion at a first degree of flexion and at a second contact point on the first curved femoral surface portion at a second degree of flexion, the second contact point being posterior to the first contact point, the second degree of flexion being greater than the first degree of flexion. The medial articular surface includes a sagittal concave curvature having a first sagittal congruity with the medial condyle at a location anterior to the dwell point at a first degree of flexion and a second sagittal congruity with the medial condyle at a location anterior to the dwell point at a second degree of flexion, the second sagittal congruity being greater than the first sagittal congruity to reduce anterior translation of the medial condyle at the second degree of flexion.

[0041] In one embodiment, the medial condyle of the femoral component includes a sagittal convex curvature, and the sagittal congruity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. In one embodiment, the first degree of flexion is approximately 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 degree of flexion is greater at the medial dwell point of the medial articular surface than at a location on the medial articular surface anterior to the medial dwell point, hi one embodiment, the medial articular surface is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0043] In one embodiment, the medial condyle and medial articular surface are more conforming to one another than the lateral condyle and lateral articular surface.

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

[0045] In one embodiment, the lateral articular surface includes an arcuate articular path having a curvature, when viewed in cross section, that includes a planar portion, a front curved portion anterior to the planar portion, and multiple rear curved portions posterior to the planar portion. The front curved portion defines a distal-most region of the lateral articular surface. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple rear curved portions decrease posteriorly.

[0046] In one embodiment, the sagittal concave curvature of the medial articular surface, when viewed in the sagittal plane, includes a plurality of curved portions, and a medial dwell point is located on the sagittal concave curvature. The plurality of curved portions includes a first curved portion adjacent to and extending posteriorly from the medial dwell point, a second curved portion adjacent to and extending anteriorly from the medial dwell point, a third curved portion adjacent to and extending anteriorly from the second curved portion, a fourth curved portion adjacent to and extending anteriorly from the third curved portion, and a fifth curved portion adjacent to and extending anteriorly 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 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 curvature of the fifth curved portion.

[0047] In one embodiment, the medial articular surface includes a coronal concave curvature defined by multiple coronal curvatures, including a first coronal curvature intersecting the sagittal concave curvature of the medial articular surface at a medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, wherein each of the first, second, and third coronal curvatures is different from one another. In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at a most anterior point of a third curved portion of the multiple curved portions defining the sagittal concave curvature of the medial articular surface, and the second 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, wherein the radius of curvature of the first coronal curvature portion is smaller than the radius of curvature of the second coronal curvature portion. In one embodiment, the third coronal curve intersects the sagittal concave curvature of the medial articular surface at a most anterior point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve 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.

[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 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 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 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, (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, (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, (ii) d is a coefficient value of -0.00015 to 0.00.

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

[0051] According to another aspect, an orthopaedic 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 and posterior to 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 of the most posterior portion of the first curved femoral surface portion. The medial articular surface is asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point defining a distal-most point on the medial articular surface. The medial condyle (i) contacts the medial dwell point at a first contact point on a first curved femoral surface portion at a first degree of flexion, the first contact point being defined by the most posterior radius of curvature of the first curved femoral surface portion, and (ii) contacts the medial dwell point at a second contact point on a second curved femoral surface portion at a second degree of flexion greater than the first degree of flexion, the second contact point being defined by a constant radius of curvature of the second curved femoral surface portion, the superior-inferior distance between the medial dwell point at the second degree of flexion and the origin of the constant radius of curvature of the second curved femoral surface portion being greater than the superior-inferior distance between the medial dwell point at the second degree of flexion and the origin of the most posterior radius of curvature of the first curved femoral surface portion at the first degree of flexion.

[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 congruity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. In one embodiment, the first degree of flexion is approximately 30 degrees.

[0053] In one embodiment, the medial articular surface includes a sagittal concave curvature, where at a medial dwell point, the sagittal concave curvature has a first sagittal congruence with the medial condyle at a first degree of flexion of the femoral component, and at a location on the medial articular surface anterior to the medial dwell point, the sagittal concave curvature has a second sagittal congruence with the medial condyle at the first degree of flexion, the second sagittal congruence being greater than the first sagittal congruence.

[0054] In one embodiment, the medial articular surface includes a coronal concave curvature, where at the medial dwell point, the coronal concave curvature has a first coronal conformity with the medial condyle at a first degree of flexion, and at a location on the medial articular surface anterior to the medial dwell point, the coronal concave curvature has a second coronal conformity with the medial condyle at the first degree of flexion, the second coronal conformity being greater than the first coronal conformity. In one embodiment, the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0055] In one embodiment, the medial condyle and medial articular surface are more conforming to one another than the lateral condyle and lateral articular surface.

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

[0057] In one embodiment, the lateral articular surface includes an arcuate articular path having a curvature, when viewed in cross section, that includes a semi-planar portion, a front curved portion located anterior to the semi-planar portion, and multiple rear curved portions located posterior to the planar portion. The planar portion defines a distal-most region of the lateral articular surface. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple rear curved portions decrease posteriorly.

[0058] In one embodiment, the sagittal concave curvature of the medial articular surface, when viewed in the sagittal plane, includes a plurality of curved portions, and a medial dwell point is located on the sagittal concave curvature. The plurality of curved portions includes a first curved portion adjacent to and extending posteriorly from the medial dwell point, a second curved portion adjacent to and extending anteriorly from the medial dwell point, a third curved portion adjacent to and extending anteriorly from the second curved portion, a fourth curved portion adjacent to and extending anteriorly from the third curved portion, and a fifth curved portion adjacent to and extending anteriorly 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 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 curvature of the fifth curved portion.

[0059] 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 a medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, wherein each of the first, second, and third coronal curvatures are different from one another.

[0060] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at a most anterior point of a third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curvature being 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, wherein the radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion.

[0061] In one embodiment, the third coronal curve intersects the sagittal concave curvature of the medial articular surface at a most anterior point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve 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.

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

[0063] In one embodiment, the distal-most point of the femoral articular surface defines 0 degrees of flexion when the femoral component is in extension, and the first curved femoral surface portion extends from a first degree of flexion of about 5 degrees to a second degree of flexion 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 the 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 that is 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 of about 65 degrees to a second flexion of about 90 degrees.

[0065] According to another aspect, an orthopaedic 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 lateral articular surface includes an arcuate articular path extending in the anterior-posterior direction, the arcuate articular path having a curvature including a planar portion when viewed in cross section, the planar portion defining a distal-most region of the lateral articular surface. The medial articular surface is asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point that defines the distal-most point of the medial condylar surface, the medial dwell point being located on the medial condylar surface between (i) a first imaginary medial-lateral bisector of the tibial insert that includes the anterior-posterior end of the flat portion of the sagittal curve of the lateral articular surface and a second imaginary medial-lateral bisector of the tibial insert that includes the posterior-posterior end of the flat portion of the sagittal curve of the lateral articular surface, and (ii) posterior to the anterior-posterior midpoint of the flat portion of the sagittal curve of the lateral articular surface.

[0066] 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 congruity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. In one embodiment, the first degree of flexion is approximately 30 degrees.

[0067] In one embodiment, the medial articular surface includes a sagittal concave curvature, where at a medial dwell point, the sagittal concave curvature has a first sagittal congruence with the medial condyle at a first degree of flexion of the femoral component, and at a location on the medial articular surface anterior to the medial dwell point, the sagittal concave curvature has a second sagittal congruence with the medial condyle at the first degree of flexion, the second sagittal congruence being greater than the first sagittal congruence.

[0068] In one embodiment, the medial articular surface includes a coronal concave curvature, where at the medial dwell point, the coronal concave curvature has a first coronal conformity with the medial condyle at a first degree of flexion, and at a location on the medial articular surface anterior to the medial dwell point, the coronal concave curvature has a second coronal conformity with the medial condyle at the first degree of flexion, the second coronal conformity being greater than the first coronal conformity. In one embodiment, the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point.

[0069] In one embodiment, the medial articular surface includes a coronal concave curvature, and the coronal congruity between the coronal concave curvature and the medial condyle is greater when the femoral component is positioned in extension than when the femoral component is positioned in later flexion.

[0070] In one embodiment, the arcuate articular path of the lateral articular surface, when viewed in cross section, has a curvature that includes a semi-planar portion, a front curved portion located anterior to the planar portion, and multiple rear curved portions located posterior to the planar portion. The semi-planar portion defines the distal-most region of the lateral articular surface. In one embodiment, each rear curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple rear curved portions decrease posteriorly.

[0071] In one embodiment, the sagittal concave curvature of the medial articular surface, when viewed in the sagittal plane, includes a plurality of curved portions, and a medial dwell point is located on the sagittal concave curvature. The plurality of curved portions includes a first curved portion adjacent to and extending posteriorly from the medial dwell point, a second curved portion adjacent to and extending anteriorly from the medial dwell point, a third curved portion adjacent to and extending anteriorly from the second curved portion, a fourth curved portion adjacent to and extending anteriorly from the third curved portion, and a fifth curved portion adjacent to and extending anteriorly 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 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 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 a medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, wherein each of the first, second, and third coronal curvatures are different from one another.

[0073] In one embodiment, the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at a distal end of a third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curvature being 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, wherein 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 curve intersects the sagittal concave curvature of the medial articular surface at a most anterior point of a fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve 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.

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

[0076] In one embodiment, the distal-most point of the femoral articular surface defines 0 degrees of flexion when the femoral component is in extension. The first curved femoral surface portion extends from a first degree of flexion of approximately 5 degrees to a second degree of flexion of approximately 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. [Figure 1] It is an exploded perspective view of an embodiment of an orthopedic knee prosthesis. [Figure 2] It is an outer perspective view of the orthopedic knee prosthesis of FIG. 1 in an assembled configuration. [Figure 3] It is a front elevation view of the orthopedic knee prosthesis of FIG. 1. [Figure 4] It is a side elevation view of an embodiment of the femoral component of the orthopedic knee prosthesis of FIG. 1. [Figure 5] 5 is a table of embodiments of ending curvature degrees of radius of curvature for a group of femoral component sizes for the femoral component of FIG. 4. [Figure 6] 5 is a table of embodiments of radius of curvature length values and corresponding ratios for a group of femoral component sizes for the femoral component of FIG. 4. [Figure 7] 5 is a table of embodiments of coefficient values of polynomials that may define the curved portion of one or more condyle surfaces of the femoral component of FIG. 4. [Figure 8] FIG. 2 is a top view of the tibial insert of the orthopaedic knee prosthesis of FIG. 1 showing the lateral arcuate articular pathway. [Figure 9] 9 is another top view of the tibial insert of FIG. 8 showing the lateral dwell region. [Figure 10] FIG. 9 is a bottom perspective view of the tibial insert of FIG. 8. [Figure 11] FIG. 9 is a bottom view of the tibial insert of FIG. 8. [Figure 12] FIG. 9 is an anterior elevational view of the tibial insert of FIG. 8. [Figure 13] FIG. 9 is a posterior elevational view of the tibial insert of FIG. 8. [Figure 14] FIG. 9 is a lateral elevational view of the tibial insert of FIG. 8. [Figure 15] FIG. 9 is a medial elevational view of the tibial insert of FIG. 8. [Figure 16] FIG. 9 is a cross-sectional view of the lateral articular surface of the tibial insert of FIG. 8 showing the lateral dwell region. [Figure 17] 9 is a cross-sectional view of the medial articular surface of the tibial insert of FIG. 8 in the sagittal plane showing the medial dwell point. [Figure 18] 9 is a perspective view of the tibial insert of FIG. 8 showing the sagittal and coronal curvature of the articular surface of the tibial insert. [Figure 19] FIG. 9 is a top view of the tibial insert of FIG. 8 showing several cross-sectional cut lines. [Figure 20] 20 is a cross-sectional view of the lateral articular surface of the embodiment of the tibial insert of FIG. 8 in a composite plane taken along line 20-20 of FIG. 19. [Figure 21]20 is a cross-sectional view of the lateral articular surface of another embodiment of the tibial insert of FIG. 8 in a composite plane taken along line 20-20 of FIG. 19. [Figure 22] 22 is a cross-sectional view of the medial articular surface of the embodiment of the tibial insert of FIG. 8 in the sagittal plane taken along line 22-22 of FIG. 19. [Figure 23] 23 is a cross-sectional view of the lateral articular surface of the embodiment of the tibial insert of FIG. 8 in the coronal plane taken along line 23-23 of FIG. 19. [Figure 24] 24 is a cross-sectional view of the medial articular surface of the embodiment of the tibial insert of FIG. 8 in the coronal plane taken along line 24-24 of FIG. 19. [Figure 25] 24 is a cross-sectional view of the medial articular surface of another embodiment of the tibial insert of FIG. 8 in the coronal plane taken along line 24-24 of FIG. 19. [Figure 26] 26 is another cross-sectional view of the medial articular surface of the embodiment of the tibial insert of FIG. 8 in the coronal plane taken along line 26-26 of FIG. 19. [Figure 27] 27 is another cross-sectional view of the medial articular surface of the embodiment of the tibial insert of FIG. 8 in the coronal plane taken along line 27-27 of FIG. 19. [Figure 28] FIG. 2 is a medial elevational view of the orthopedic knee prosthesis of FIG. 1 at approximately 0 degrees of flexion. [Figure 29] FIG. 2 is a medial elevational view of the orthopedic knee prosthesis of FIG. 1 in approximately 35 degrees of flexion. [Figure 30] FIG. 2 is a medial elevational view of the orthopedic knee prosthesis of FIG. 1 in approximately 90 degrees of flexion. [Figure 31] FIG. 2 is a medial elevational view of the orthopedic knee prosthesis of FIG. 1 in approximately 110 degrees of flexion. [Figure 32] 32 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 28 in the coronal plane taken along line 32-32 of FIG. 28. [Figure 33] 33 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 28 in a horizontal plane taken along line 33-33 of FIG. 28. [Figure 34]29 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 28 in the sagittal plane along the medial dwell point of the medial articular surface of the tibial insert of the orthopedic knee prosthesis of FIG. 28. [Figure 35] 35 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 29 in the coronal plane taken along line 35-35 of FIG. 29. [Figure 36] 36 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 29 in a horizontal plane taken along line 36-36 of FIG. 29. [Figure 37] 30 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 29 in the sagittal plane along the medial dwell point of the medial articular surface of the tibial insert of the orthopedic knee prosthesis of FIG. 29. [Figure 38] 38 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 30 in the coronal plane taken along line 38-38 of FIG. 30. [Figure 39] 39 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 30 in a horizontal plane taken along line 39-39 of FIG. 30. [Figure 40] 31 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 30 in the sagittal plane along the medial dwell point of the medial articular surface of the tibial insert of the orthopedic knee prosthesis of FIG. 30. [Figure 41] 41 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 31 in the coronal plane taken along line 41-41 of FIG. 31. [Figure 42] 42 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 31 in a horizontal plane taken along line 42-42 of FIG. 31. [Figure 43] 32 is a cross-sectional view of the orthopedic knee prosthesis of FIG. 31 in the sagittal plane along the medial dwell point of the medial articular surface of the tibial insert of the orthopedic knee prosthesis of FIG. 31. [Figure 44] 2 is a lateral elevational view of the orthopedic knee prosthesis of FIG. 1 bent to a degree of flexion and showing contact points defined by a radius of curvature. [Figure 45] 45 is a lateral elevational view of the orthopedic knee prosthesis of FIG. 1 bent to a slightly greater degree of flexion than FIG. 44 and showing different contact points defined by different radii of curvature. DETAILED DESCRIPTION OF THE INVENTION

[0079] While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that there is no intention to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the 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 denoting anatomical references, such as anterior, posterior, medial, lateral, superior, inferior, etc., 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 biological anatomy of a patient. Such terms have well-understood meanings both in the study of anatomy and in the field of orthopedic surgery. The use of such anatomical reference terms in the written description and claims is intended to be consistent with their well-understood meanings unless otherwise specified. Additionally, the term "about" may be used herein with respect to particular dimensions that are defined within manufacturing tolerances. That is, the dimensions and / or numerical values provided may, in reality, deviate due to tolerances inherent in the machine or manufacturing process.

[0081] References herein to "one embodiment," "embodiment," "exemplary example," and the like 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. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular element, structure, or feature is described in connection with one embodiment, it is believed to be within the knowledge of one of ordinary skill in the art to implement such element, structure, or feature in connection with other embodiments, whether or not expressly stated. Furthermore, it should be understood that items listed in the format "at least one of A, B, and C" can mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). Similarly, items listed in the format "at least one of A, B, or C" can mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

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

[0083] 1-3 , in an exemplary embodiment, an orthopaedic knee prosthesis 100 includes a femoral component 102 and a tibial insert 104. Additionally, the orthopaedic 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 tibial tray) are illustratively formed from a metallic material such as cobalt chromium or titanium, but may be formed from other materials, such as ceramic, polymeric, or bioengineered materials, in other embodiments. The tibial insert 104 is illustratively formed from a polymeric material such as ultra-high molecular weight polyethylene (UHMWPE), but may be formed from other materials, such as ceramic, metallic, or bioengineered materials, in other embodiments.

[0084] The femoral component 102 is configured to be coupled to a surgically prepared surface of the distal end of a patient's femur (not shown), and the tibial insert 104 is configured to be coupled to a surgically prepared surface of the proximal end of the 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 attach directly to the surgically prepared surface of the proximal end of the patient's tibia without the use of a tibial tray. For example, the tibial insert 104 and a polymer "tray" may be combined into a single polymer component.

[0085] In use, the femoral component 102 is configured to articulate with the tibial insert 104. To do so, the femoral component includes an outer articulating 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. Thus, 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.

[0086] As described in more detail below, the femoral component 102 and the tibial insert 104 each include articular curvatures and associated features that facilitate or promote pivoting of the lateral condyle 112 at the lateral articular surface 122 while limiting or reducing anterior 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 sagittal condylar surfaces having curved portions defined by continuously decreasing radii of curvature. Furthermore, the medial articular surface 124 has a concave sagittal curvature that generally better matches the convex sagittal curvature of the medial condyle 114 at mid-flexion (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 accommodate asymmetric pivoting of the femoral component 102 on the tibial insert 104. Additionally, the lateral articular surface 122 and the lateral condyle 112 may be less conformable with one another than the medial articular surface 124 and the medial condyle 114. Further, as described below, the coronal curvature of the lateral articular surface 122 is uniform in the anterior-posterior direction, while the coronal curvature of the medial articular surface 124 is non-uniform in the anterior-posterior direction (e.g., the coronal curvature of the medial articular surface 124 is defined by multiple different coronal curvatures). Additionally, the medial articular surface 124 may conform more to the medial condyle 114 in extension compared to flexion, and more anterior to the dwell point of the medial condyle 114 than the dwell point, due to the sagittal shape of the medial articular surface 124 (see the description of Figures 18-27 below). It should be appreciated that the sagittal curvature of the femoral condyles 112, 114, the overall sagittal congruity 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 congruity in extension and anterior to the dwell point of the medial condyle 114 improve the stability of the orthopedic knee prosthesis 100, facilitate pivoting of the lateral femoral condyle 112, and reduce or limit medial anterior translation of the femur.

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

[0088] Referring now to FIG. 4 , one or both of the condyles 112, 114 of the femoral component 102 includes a convexly curved convex surface 400 in the sagittal plane. Illustratively, the condyle surface 400 is formed from several curved portions 402, 404, 406, 408, 410, and 412, each of which is in contact with an adjacent curved portion. Each curved portion 402, 404, 406, 408, 410, and 412 contacts the tibial bearing insert through a different range of flexion. For example, the curved portions 402, 404 of the condyle surface 400 contact the tibial insert 104 during early flexion. The curved portions 406, 408 of the condyle surface 400 contact the tibial insert 104 during mid-flexion. Additionally, the curved portions 410, 412 of the condyle surface 400 contact the tibial insert 104 during end-flexion.

[0089] Each curved surface portion 402, 406, 408, 410, and 412 is defined by a constant radius of curvature R1, R3, R4, R5, and R6, respectively. However, as explained in more detail below, curved surface portion 404 is defined by multiple lines rather than a constant radius of curvature. In particular, curved surface portion 3604 is designed so that condyle surface 400 gradually transitions from radius of curvature R1 of curved surface portion 402 to radius of curvature R2 tangent to curved surface portion 406. Thus, curved surface portion 3604 has a continuously decreasing radius of curvature.

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

[0091] As shown in FIG. 6 , table 600 defines the lengths of each radius 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 radius of curvature R1, R2, R3, R4, R5, and R6 for each size of femoral component 102 1-10 may vary across sizes, but the ratios of R1 / R2, R1 / R3, and R1 / R4 may remain relatively constant or vary slightly across femoral component sizes. For example, the ratio of radius of curvature R1 to radius of curvature R2 may vary from approximately 1.347 to 1.355 to maintain a value of approximately 1.350 across femoral component sizes 1-10. Similarly, the ratio of radius of curvature R1 to radius of curvature R3 may vary from approximately 1.277 to 1.278 to maintain a value of approximately 1.280 across femoral component sizes 1-10. Additionally, the ratio of radius of curvature R1 to radius of curvature R4 may be maintained at a value of approximately 1.305 across femoral component sizes 1-10.

[0092] It should also be appreciated that the condyle surface 400 of the femoral component 102, in some embodiments, is designed such that the radius of curvature R3 is greater than the radius of curvature R2 by an amount ranging from about 0.5 millimeters to about 5 millimeters. As discussed below, the particular amount of increase may, in some embodiments, be based on the size of the femoral component. Further, based on the above analysis, the condyle surface 400 is designed such that the increase in radius of curvature from R2 to R3 occurs at degrees of flexion ranging from about 45 degrees to about 90 degrees. In one particular embodiment, the increase in radius of curvature from R2 to R3 occurs at the condyle surface 400 at about 65 degrees of flexion.

[0093] As described above, the curved portion 404 is designed to provide a gradual transition from radius of curvature R1 to radius of curvature R2. Accordingly, the magnitude of the angle defined by the curved portion 404 can be selected based on the desired rate of transition. For example, in some embodiments, the condyle surface 400 of the femoral component 102 is designed such that the curved portion 404 extends from a first degree of flexion ranging from about 0.0 to about 30.0 degrees to a second degree of flexion ranging from about 45.0 to about 90.0 degrees. In one particular embodiment, the curved portion 404 extends from about 5.0 degrees of flexion to about 65.0 degrees of flexion, 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 the size of the femoral component 102, determined according to the size, or otherwise affected by the size. 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 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 translation (e.g., medial forward translation) of the femoral component 102 with respect 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 for embodiments designed using the metric unit system. 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 location of the common origin O of the multiple lines 420. By limiting the distance between the common origin O of the multiple lines 420 and the origin 422 of the radius of curvature R1 that defines the curved surface portion 402 in initial flexion, paradoxical forward sliding of the femoral component 102 on the tibial insert 104 can be reduced or delayed. Accordingly, in one embodiment, the location of the common origin O of the multiple 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 approximately 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, in some embodiments, on the specific size of the femoral component 102. An exemplary embodiment 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) is shown in table 700 of FIG. 7.

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

[0102] 8-18 , the exemplary tibial insert 104 includes a body 800 that includes asymmetric lateral and medial articular surfaces 122, 124. The medial articular surface 124 includes a dwell point 802 that defines the distal-most point of the medial articular surface 124 and generally the contact point or area where the medial condyle 114 of the femoral component 102 contacts the medial articular surface 124 during articulation (although some contact between the femoral component 102 and the tibial insert 104 may occur anterior to the medial dwell point 802 at some degrees of flexion and depending on the loading of the femoral component 102 and the tibial insert 104).

[0103] Illustratively, the dwell point 802 is positioned on the medial articular surface 124 relative to the anterior sidewall 810 of the body 800 of the tibial insert 104. For example, in the illustrative embodiment, the dwell point 802 is located on the medial articular surface 124 at a distance 820 that is approximately 63.3% of the total medial anterior-posterior length 822, defined as the distance from the most anterior point on the anterior sidewall 810 to the most posterior point on the posterior sidewall 812 on the medial side of the body 800 of the tibial insert 104 (i.e., measured across the medial articular surface 124). It should be understood that in some embodiments, the lateral articular surface 122 and the medial articular surface 124 may have different anterior-posterior lengths due to different posterior-posterior points on the posterior sidewall 812.

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

[0105] The dwell region 804 lies on an arcuate joint path 806 of the lateral articular surface 122, which defines the path of contact points between the lateral condyle 112 and the lateral articular surface 122 of the femoral component 102 through flexion of the femoral component 102 (although the lateral condyle 112 may not travel 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 of the dwell point 802 of the medial articular surface 124. In the illustrative 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 distal-most points of each condyle 112, 114). Thus, the curvature of the lateral articular surface 122 is designed to allow the femoral component 102 to pivot or rotate relative to the dwell point 802 along the arcuate articular path 806 during flexion of the femoral component 102. That is, as the femoral component 102 is moved from extension to flexion, the contact point between the lateral condyle 112 of the femoral component 102 and the lateral articular surface 122 moves posteriorly along the arcuate path 806.

[0106] Similar to the dwell point 802, the dwell point 804 is illustratively positioned on the lateral articular surface 122 relative to the anterior sidewall 810 of the body 800 of the tibial insert 104. For example, in the illustrative embodiment, the dwell point 804 is located on the lateral articular surface 122 at a distance 920 that is approximately 62.6% of the total lateral anterior-posterior length 922, which is defined as the distance from the most anterior point on the anterior sidewall 810 to the most posterior point on the posterior sidewall 812 on the lateral side of the body 800 of the tibial insert 104 (i.e., measured across the lateral articular surface 122). Again, it should be understood that in some embodiments, the lateral articular surface 122 and the medial articular surface 124 may have different anterior-posterior lengths due to the different posterior-most points on the posterior sidewall 812.

[0107] Additionally, as shown in Figure 9, a dwell point 802 of the medial articular surface 124 is spatially related to a dwell region 804 of the lateral articular surface 122. Specifically, the dwell region 804 has a length 900 defined as the distance between an anterior-most end 902 of the dwell region 804 (shown as a solid dot in Figure 9) and a posterior-most end 904 of the dwell region 804 (also shown as a solid dot in Figure 9), and the dwell point 802 is located on the medial articular surface 124 between the anterior-most end 902 and the posterior-most end 904 of the dwell region 804. That is, the dwell point 804 is located on the medial articular surface 124 between an anterior imaginary medial-lateral bisector 910 that includes the anterior-most end 902 of the dwell region 804 and a posterior imaginary medial-lateral bisector 912 that includes the posterior-most end 904 of the dwell region 804. Additionally, as shown in Figure 9, the dwell point 804 is located on the medial articular surface 124 posterior to the midpoint 906 of the dwell region 804 (shown as a solid point in Figure 9). That is, the dwell point 804 is located on the medial articular surface 124 posterior to an imaginary medial-lateral bisector 914 that contains the midpoint 906 of the dwell region 804.

[0108] 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. The illustrative tibial insert 104 includes a posterior channel 1002 sized and shaped to receive a posterior buttress of the tibial tray. The posterior channel 1002 is defined by a sidewall 1004, which includes a flange 1006 extending inwardly into the posterior channel 1002 and positioned to be received in a corresponding undercut of the tibial tray. The tibial insert 104 also includes an anterior channel 1010 sized and shaped to receive a corresponding anterior buttress of the tibial tray. In this manner, the channels 1002, 1010 cooperate with corresponding features of the tibial tray to secure the tibial insert 104 on the tibial tray in a single orientation relative to the tibial tray. It should be understood that in other embodiments, the tibial insert 104 and corresponding tibial tray may include mobile bearing interface surfaces that allow the tibial insert 104 to move independently of the corresponding tibial tray. Additionally, as described above, the tibial insert 104 may, in some embodiments, be configured for direct attachment to the patient's tibia. In such embodiments, the tibial insert 104 may not include the features described above for coupling to a tibial tray, but may include other shapes that allow the tibial insert 104 to be directly implanted into the patient's bony anatomy.

[0109] As described above, the medial articular surface 124 and the lateral articular surface 122 are asymmetrical relative to one another. For example, as best shown in FIGS. 12-17 , the medial articular surface 124 has a taller anterior lip than the anterior lip of the lateral articular surface 122. For example, as shown in FIG. 16 , the lateral articular surface 122 includes a lateral anterior lip 1600 that defines a lip or rim of the anterior sidewall 810 on the lateral side. The lateral anterior lip 1600 has a lip height 1602 that is defined by the vertical distance (i.e., the vertical distance) between the lateral dwell point / region 804 of the tibial insert 104 and the lateral anterior lip 1600. Similarly, as shown in FIG. 17 , the medial articular surface 124 includes a medial anterior lip 1700 that defines a lip or rim of the anterior sidewall 810 on the medial side. The medial anterior lip 1700 has a lip height 1702 defined by the vertical distance (i.e., the up-down distance) between the medial dwell point 802 of the tibial insert 104 and the medial anterior lip 1700. In the illustrative embodiment, the lip height 1702 of the medial anterior lip 1700 is greater than the lip height 1602 of the lateral anterior lip 1600.

[0110] Additionally, the dwell point 802 of the medial articular surface 124 is positioned such that the ratio of the distance 1710 between the medial dwell point 802 and the anterior sidewall 810 to the lip height 1702 is relatively constant across sizes of the tibial insert 104. For example, in one exemplary embodiment, the ratio of the lip height 1702 to the dwell point distance 1710 ranges from 18.9% to 20.9% depending on the size of the tibial insert 104.

[0111] 18-27, as described above, the lateral articular surface 122 and the medial articular surface 124 have different contours such that the articular surfaces 122, 124 are asymmetrical relative to one another. For example, as shown in FIG. 18, the lateral articular surface 122 includes a concave curvature 1802 when viewed in a composite anterior-posterior cross section along the arcuate joint path 806. It should be understood that the composite anterior-posterior concave curvature 1802 of the arcuate joint path 806 does not lie in a single sagittal plane due to the arcuate shape of the arcuate joint path 806 when viewed in a horizontal plane. Additionally, the lateral articular surface 122 has a concave curvature 1812 when viewed in a cross section perpendicular to the arcuate joint path 806. The cross-sectional concave curvature 1812 is uniform at each point along the arcuate joint path 806 (as indicated by the multiple 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 (also curvature 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 lie directly on the coronal plane of the lateral articular surface 122 due to the arcuate shape of the arcuate joint path 806 when viewed in a horizontal plane.

[0112] Conversely, the medial articular surface 124 is defined by a sagittal concave curvature 1804 and multiple non-uniform coronal curvatures 1814, 1824, 1834. However, as shown in FIGURE 18 , posterior to the medial dwell point 802, the coronal curvature of the medial articular surface 124 is uniform and defined by the coronal curvature 1814. Conversely, anterior to the medial dwell point 802, the coronal curvature of the medial articular surface is non-uniform and 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 degrees of 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 area) 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 degree of 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 a particular degree of flexion. That is, at a particular degree of flexion, the coronal congruity between the coronal curvature 1824 and the condylar surface 400 of the medial condyle 114 is greater than the coronal congruity between the coronal curvature 1814 (e.g., at the medial dwell point 802) and the condylar surface 400 of the medial condyle 114. It should also be understood that while the coronal curvature of the medial articular surface 124 is designed to avoid impingement and / or unintended contact between the femoral component 102 and the tibial insert 104, the coronal congruity between the medial articular surface 124 and the medial condyle 114 increases anterior to the medial dwell point 802 at a particular degree of flexion (e.g., 30.0 degrees of flexion), such that anterior translation of the medial condyle 114 may be limited, restricted, or otherwise reduced.

[0114] 20 , an exemplary embodiment of the anterior-posterior compound concave curvature 1802 of the lateral articular surface 122 is shown in 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 anterior-posterior compound concave curvature 1802 includes a sub-flat portion 2000 corresponding to the dwell region 804, a first set of curved portions extending posterior to the flat portion 2000, and an anterior curved portion 2006 extending anterior to 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 discussed above, flat portion 2000 (i.e., dwell region 804) is quasi-planar and extends from forward-most end 902 to aft-most end 904. Again, flat portion 2000 is "quasi-planar" in that it may be defined as a planar portion, as shown in FIG. 20 , or as a curved portion having a radius large enough to approximate a planar portion. For example, in the exemplary embodiment, 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 defining either adjacent curved portion (i.e., curved portion 2012 and curved portion 2016). In such an embodiment, flat portion 2000 includes a dwell point 2090 that defines the distal-most point of flat portion 2000 and extends approximately 1.15 degrees forward of dwell point 2090 and approximately 1.58 degrees rearward of dwell point 2090 for a total arc length of approximately 2.73 degrees.

[0116] Illustratively, the first curved portion 2002 of the first set of curved portions extends posteriorly from the posteriormost end 904 of the flat portion 2000 for approximately 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 posteriorly therefrom for an arc length ranging from approximately 13.2 degrees to approximately 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 the illustrative embodiment, the radius of curvature 2014 is less than the radius of curvature 2012 (i.e., the radius of curvature of the anterior-posterior compound concave curvature 1802 decreases posteriorly). However, in other embodiments, the first set of curved portions extending posteriorly from the flat portion 2000 may include additional curved portions to smoothly open the posterior side of the anterior-posterior compound concave curve 1802 and / or may be defined by a gradually or continuously decreasing radius, as described above with respect to the femoral component 102.

[0117] The anterior curved portion 2006 extends anteriorly from the anterior-most end 902 of the flat portion 2000 over an arc length ranging from 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 less than the radius of curvature 2012 and greater than the radius of curvature 2014.

[0118] 21 , in another embodiment, the anterior-posterior compound concave curvature 1802 may include a flat or planar portion 2100 corresponding to the dwell 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 discussed above, the flat portion 2100 (i.e., the dwell region 804) extends from the forward-most end 902 to the aft-most 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. And, 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 posteriorly from the flat portion 2100 may include additional curved portions to smoothly open up the posterior side of the anterior-posterior compound concave curve 1802 and / or may be defined by a gradually or continuously decreasing radius, as described above with respect to the femoral component 102. In the exemplary embodiment, the radii of curvature of the first second curved portions increase posteriorly. That is, radius of curvature 2128 is greater than radius of curvature 2126, which is greater than radius of curvature 2124, which is greater than 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. The sixth curved portion 2112 extends over approximately 35.0 degrees and is defined by a radius of curvature 2132. In the illustrative embodiment, the radius of curvature 2130 is greater than the radius of curvature 2132.

[0121] 22, an exemplary embodiment of the medial sagittal concave curvature 1804 of the tibial insert 104 is shown in cross section generally along line 22-22 in 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 and anterior to the first curved portion 2200, a third curved portion 2204 adjacent to and anterior to the second curved portion 2202, a fourth curved portion 2206 adjacent to and anterior to the third curved portion, and a fifth curved portion 2208 adjacent to and posterior to the first curved portion 2200. Illustratively, a medial dwell point 802 is at the intersection of the first curved portion 2200 and the fifth curved portion 2208. However, in other embodiments, the dwell point 802 may be on the first curved portion 2200 or the fifth curved portion 2208 .

[0122] The first curved portion 2200 extends anteriorly from the dwell point 802 over approximately 5.2 degrees and is defined by a constant radius of curvature 2210. The second curved portion 2202 extends anteriorly from the first curved portion 2200 over an arc length ranging from 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 anteriorly from the second curved portion 2202 over an arc length ranging from 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 anteriorly from the third curved portion 2204 over an arc length ranging from 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. Additionally, fifth curved portion 2208 extends posteriorly from first curved portion 2200 through an arc length ranging from about 15.9 degrees to about 17.4 degrees, depending on the size of the tibial insert 104, and is defined by a constant radius of curvature 2218. In the exemplary embodiment, radius of curvature 2218 is greater than radius of curvature 2210. Furthermore, in the exemplary embodiment, radius of curvature 2212 is less than each of radii of curvature 2210, 2214, and 2216.

[0123] The medial sagittal concave curvature 1804 of the tibial insert 104 may be shaped differently to have different curvatures in other embodiments. For example, in another embodiment, the second curved portion 2202 may extend anteriorly from the first curved portion 2200 by approximately 24.8 degrees. The third curved portion 2204 may extend anteriorly from the second curved portion 2202 by approximately 15.0 degrees. And, the fifth curved portion 2208 may extend posteriorly from the first curved portion 2200 by 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 across degrees of flexion. For example, as 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 degree of flexion (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 across the full sagittal curvature, not just at a particular contact point) can be defined as the overall amount of gap between these curvatures at a particular degree of flexion. 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 by a maximum amount at a particular degree of flexion (e.g., 30 degrees of flexion). Sagittal conformance may be further increased under loading conditions (i.e., the femoral component 102 may be forced further against the tibial insert 104, further increasing sagittal conformance at a particular degree of flexion). The increased overall sagittal conformance between the medial condyle 114 and the medial articular surface 124 during flexion compared to extension may reduce anterior translation of the femoral component 102 at the medial articular surface 124 at that particular degree of flexion (e.g., 30 or 35 degrees of flexion).

[0125] Additionally, at a particular 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 that the radius of curvature defining the sagittal curvature of the medial articular surface 124 at a particular 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 fourth curved portion 2206 and the condylar surface 400 of the medial condyle 114 at a particular degree of flexion (e.g., 30.0 degrees of flexion) than between the first curved portion 2200 and the condylar surface 400 of the medial condyle 114 at a particular degree of flexion. That is, at a particular degree of flexion, the sagittal congruity at the point (or area) of contact between the first curved portion 2200 and the condylar surface 400 of the medial condyle 114 is greater than the sagittal congruity at the point (or area) of contact between the fourth curved portion 2206 and the condylar surface 400 of the medial condyle 114. Thus, it should be understood that because the sagittal congruity between the medial articular surface 124 and the medial condyle 114 increases anterior to the medial dwell point 802 at a particular degree of flexion (e.g., 30.0 degrees of flexion), anterior translation of the medial condyle 114 at the medial articular surface 124 may be limited, restricted, or otherwise reduced.

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

[0127] 23, an exemplary embodiment of the cross-sectional concave curvature 1812 of the lateral articular surface 122 of the tibial insert 104 is shown in cross-section generally along line 23-23 in FIG. 19, which generally corresponds to the uniform cross-sectional curvature 1812 of FIG. 18. As discussed above, in the exemplary embodiment, the cross-sectional curvature 1812 of the lateral articular surface 122 is uniform along the anterior-posterior compound concave curvature 1802 and has a single curved portion 2300 having a constant radius of curvature 2302. The curved portion 2300 extends medially (i.e., medially) of the lateral dwell region 804 over approximately 25 degrees and laterally (i.e., lateral) of the lateral dwell region 804 over an arc length ranging from about 18.7 degrees to about 31.1 degrees, depending on the size of the tibial insert 104. Additionally, the cross-sectional curvature 1812 of the lateral articular surface 122 includes a flat portion 2310 that is tangent to the innermost point of the curved portion 2300 and extends medially (i.e., medially) thereof. Additionally, as shown in FIG. 23 , the flat portion 2310 is inclined at an angle 2320 of approximately 25.0 degrees relative to the bottom surface 1000 of the tibial insert 104. The size, shape, and orientation of the flat portion 2310 may be selected or designed to match the inner shape of the femoral component 102 and / or to avoid impingement of the femoral component 102.

[0128] 24, an exemplary embodiment of the coronal curvature 1814 of the tibial insert 104 is shown in cross section generally along line 24-24 in FIG. 19, which generally corresponds to the coronal curvature 1814 in FIG. 18. In the exemplary embodiment, the coronal curvature 1814 of the medial articular surface 124 is uniform posterior to the medial dwell 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 lateral (i.e., medially) from the medial dwell point 802 and extends an arc length ranging from approximately 18.6 degrees to approximately 26.8 degrees medially from the medial dwell point 802, for a total arc length of approximately 43.6 degrees to approximately 51.8 degrees, depending on the size of the tibial insert 104. Additionally, the coronal curvature 1814 of the medial articular surface 124 includes a flat portion 2410 tangent to and extending lateral (i.e., medially) from the outermost point of the curved portion 2400. As shown in FIG. 24 , the flat portion 2410 is inclined at an angle 2420 of approximately 25.0 degrees relative 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 impingement of the femoral component 102.

[0130] In other embodiments, the coronal curvature 1814 may be defined by multiple 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 dwell point 802 resides, and a second curved portion 2502 located adjacent to (i.e., outboard 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 embodiments, the radius of curvature 2512 may be greater than the radius of curvature 2510. Additionally, the coronal curvature 1814 in FIG. 25 may include a flat portion 2504 tangent to and extending outboard (i.e., inboard) of the curved portion 2500 at its outermost point. Similar to the planar portion 2410, the planar portion 2504 may be angled at an angle of approximately 25.0 degrees relative to the bottom surface 1000 of the tibial insert 104.

[0131] 26, an exemplary embodiment of the coronal curve 1824 of the tibial insert 104 is shown in cross section generally along line 26-26 in FIG. 19, which generally corresponds to the coronal curve 1824 in FIG. 18. The coronal curve 1824 intersects the sagittal concave curve 1804 at the anterior-most point of the second curved portion 2202, which defines the medial sagittal concave curve 1804 (see FIG. 22). The coronal curve 1824 includes a flat or planar portion 2600 having an outer end 2602 (i.e., medial end) and an inner end 2604 (i.e., lateral 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 ranging from 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 ranging from 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 greater than the radius of curvature 2616.

[0132] 27, an exemplary embodiment of the coronal curve 1834 of the tibial insert 104 is shown in cross section generally along line 27-27 in FIG. 19, which generally corresponds to the coronal curve 1834 in FIG. 18. The coronal curve 1834 intersects the sagittal concave curve 1804 at the anterior-most point of the third curved portion 2204, which defines the medial sagittal concave curve 1804 (see FIG. 22). Similar to the coronal curve 1824, the coronal curve 1834 includes a flat or planar portion 2700 having an outer end 2702 (i.e., the medial end) and an inner end 2704 (i.e., the lateral end), a first curved portion 2706 extending from the medial 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 flat portion 2700 may be angled at approximately 6.0 degrees relative to the bottom surface 1000 of the tibial insert 104. The first curved portion 2706 extends over an arc length ranging from approximately 0.3 degrees to approximately 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 ranging from approximately 16.4 degrees to approximately 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 greater than the radius of curvature 2718.

[0133] 28-43, as described above, the femoral component 102 is configured to articulate on the tibial insert 104 through a range of degrees of flexion. For example, in FIG. 28, the femoral component 102 is shown in extension (i.e., 0 degrees of flexion). In FIG. 29, the femoral component 102 has articulated to approximately 35 degrees of flexion. In FIG. 30, the femoral component 102 has articulated to approximately 90 degrees of flexion. And, in FIG. 31, the femoral component 102 has articulated to approximately 110 degrees of flexion.

[0134] As discussed above, the condyles 112, 114 of the femoral component 102 may have different amounts of conformance with the articular surfaces 122, 124 at different degrees of flexion. For example, FIGS. 32-34 show the orthopedic prosthesis 100 at approximately 0.0 degrees of flexion. As shown in FIG. 32, the femoral component 102 and tibial insert 104 have increased coronal conformance when in extension. Furthermore, as shown in FIG. 33, the femoral component 102 has only a slight pivot or rotation on the tibial insert 104. Furthermore, as shown in FIG. 34, the medial condyle 114 and medial articular surface 124 have overall sagittal conformance (i.e., the amount of space between the sagittal curvature of the medial condyle 114 and medial articular surface 124) in extension.

[0135] 35-37 show the orthopedic prosthesis 100 in 35.0 degrees of flexion. As shown in FIG. 35, the femoral component 102 and tibial insert 104 have slightly less coronal conformance than in the extended position. Additionally, as shown in FIG. 36, the femoral component 102 has pivoted or rotated a greater amount on the tibial insert 104. Furthermore, as shown in FIG. 37, the medial condyle 114 and medial articular surface 124 have increased overall sagittal conformance compared to 0.0 degrees of flexion in FIG. 34.

[0136] 38-40 show the orthopaedic prosthesis 100 in approximately 90 degrees of flexion. As shown in FIG. 38, the femoral component 102 and tibial insert 104 have less coronal conformance than at 35 degrees of flexion in FIGS. 34 and 35. Additionally, as shown in FIG. 39, the femoral component 102 has pivoted or rotated on the tibial insert 104 to a greater amount than at 35 degrees of flexion in FIGS. 35 and 36. Furthermore, as shown in FIG. 40, the medial condyle 114 and medial articular surface 124 have reduced overall sagittal conformance compared to at 35 degrees of flexion in FIG. 37.

[0137] 41-43 show the orthopaedic prosthesis 100 in approximately 110 degrees of flexion. As shown in FIG. 41, the femoral component 102 and the tibial insert 104 have less coronal conformance than at 90 degrees of flexion in FIGS. 38 and 39. Additionally, as shown in FIG. 42, the femoral component 102 has pivoted or rotated on the tibial insert 104 to a greater amount than at 90 degrees of flexion in FIGS. 38 and 39. Furthermore, as shown in FIG. 43, the medial condyle 114 and the medial articular surface 124 have further reduced overall sagittal conformance than at 90 degrees of flexion in FIG. 40.

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

[0139] 44 shows the femoral component 102 in a first degree of flexion, where a 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 a dwell point 802 of the tibial insert 104 and is defined by a most posterior radius 4402 of the plurality of decreasing radii that define the curved portion 404. The most posterior radius 4402 has an origin 4404 that is a distance 4410 from the medial dwell point 802.

[0140] 45 , the femoral component 102 has been moved to a second degree of flexion that is slightly greater than the first degree of flexion, where a contact point 4500 between the condylar surface 400 of the medial condyle 114 of the femoral component 102 and the tibial insert 104 is located at a dwell point 802 of the tibial insert 104 and is defined by a constant radius of curvature 4502 (i.e., 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 a distance 4510 from the medial dwell point 802. It should be appreciated that the distance 4510 between the origin 4504 and the medial dwell point 802 is greater than the distance 4410 between the origin 4404 and the medial dwell point 802. Therefore, the increase in the distance between the origins 4404, 4504 as the contact point between the femoral component 102 and the tibial insert 104 moves from the curved portion 404 to the curved portion 406 of the condylar surface 400 of the medial condyle 114 elongates the tibial-femoral envelope, thereby increasing tension in the ligaments of the knee joint and may improve knee joint stability.

[0141] While the present disclosure has been illustrated and described in detail in the drawings and foregoing description, it will be understood that such illustration and description are to be regarded as illustrative in nature and not as restrictive, having merely shown and described exemplary embodiments, and that all changes and modifications that come within the spirit and scope of the present disclosure are desirably protected.

[0142] The present disclosure has multiple advantages based on various features of the methods, apparatus, and / or systems described herein. It should be noted that alternative embodiments of the methods, apparatus, and systems of the present disclosure may not include all of the described features, but still benefit from at least some of the advantages of such features. Those skilled in the art will readily be able to independently implement methods, apparatus, and systems that incorporate one or more of the features of the present invention and are within the spirit and scope of the present disclosure as defined in the appended claims.

[0143] [Embodiment] (1) A tibial insert, an lateral articular surface configured to articulate with a lateral condyle of a femoral component, the lateral articular surface including an arcuate articular path extending in an anterior-posterior direction, the arcuate articular path being defined by a plurality of points on the lateral articular surface, such that when the tibial insert is viewed in a medial-lateral cross section at each point, each point defines a distal-most point of the lateral articular surface in the corresponding medial-lateral cross section, the lateral articular surface having a cross-sectional concave curvature perpendicular to the arcuate articular path, the cross-sectional concave curvature being uniform at each of the plurality of points; a medial articular surface configured to articulate with the medial condyle of the femoral component, the medial articular surface being asymmetrically shaped relative to the lateral articular surface and having a non-uniform coronal concave curvature in the anterior-posterior direction. (2) The tibial insert of embodiment 1, wherein the medial articular surface includes a medial dwell point defining the most distal point of the medial articular surface, and the coronal concave curvature of the medial articular surface is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point. (3) the arcuate joint path, when viewed in cross section, has a curvature including a semi-planar portion, a forward curved portion located anterior to the planar portion, and a plurality of rearward curved portions located posterior to the planar portion; 2. The tibial insert of claim 1, wherein the semi-planar portion defines a lateral dowel region that defines the distal-most region of the lateral articular surface. (4) A tibial insert according to embodiment 3, wherein each posterior curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple posterior curved portions decrease posteriorly. (5) The tibial insert according to embodiment 3, wherein the plurality of posterior curved portions include a first posterior curved portion adjacent to the rearmost end of the planar portion and a second posterior curved portion adjacent to the first posterior curved portion, and the radius of curvature of the first posterior curved portion is greater than the radius of curvature of the second posterior curved portion.

[0144] (6) The tibial insert of embodiment 5, wherein 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. (7) The tibial insert of embodiment 5, wherein the anterior curved portion extends over an arc length ranging from 33.5 degrees to 34.4 degrees, the first posterior curved portion extends over an arc length ranging from approximately 3.4 degrees, and the second posterior curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees. (8) The tibial insert of embodiment 1, wherein the medial articular surface, when viewed in the sagittal plane, includes a sagittal concave curvature defined by a plurality of curved portions and a medial dwell point defining the most distal point of the medial articular surface, the medial dwell point being located on the sagittal concave curvature. (9) The tibial insert of embodiment 8, wherein the plurality of curved portions include a first curved portion adjacent to the medial dwell point and extending posteriorly therefrom, and a second curved portion adjacent to the medial dwell point and extending anteriorly therefrom, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. (10) The tibial insert of embodiment 9, wherein the first curved portion extends over an arc length ranging from 15.9 degrees to 17.4 degrees and the second curved portion extends over approximately 5.2 degrees.

[0145] (11) The tibial insert of embodiment 9, wherein the plurality of curved portions include a third curved portion adjacent to the second curved portion and extending anteriorly therefrom, a fourth curved portion adjacent to the third curved portion and extending anteriorly therefrom, and a fifth curved portion adjacent to the fourth curved portion and extending anteriorly therefrom, 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. (12) The tibial insert of embodiment 11, wherein 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. (13) The tibial insert of embodiment 11, wherein the coronal concave curvature of the medial articular surface is defined by a plurality of coronal curvatures, including a first coronal curvature that intersects with the sagittal concave curvature of the medial articular surface at the medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other. (14) The tibial insert of embodiment 13, wherein the first coronal curve is defined by a coronal curve portion extending from the medial dwell point medially over an arc length ranging from 18.6 degrees to 26.8 degrees and from the medial dwell point laterally over approximately 25.0 degrees. (15) The tibial insert of embodiment 13, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second coronal curve is defined by a planar portion having a medial end and an 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.

[0146] (16) The tibial insert according to embodiment 15, wherein the radius of curvature of the first coronal curve portion of the second coronal curve is smaller than the radius of curvature of the second coronal curve portion of the second coronal curve. (17) The tibial insert of embodiment 16, wherein the first coronal curve of the second coronal curve portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curve portion of the second coronal curve extends over an arc length in the range of 20.1 degrees to 28.5 degrees. (18) The tibial insert of embodiment 15, wherein the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve is defined by a planar portion having a medial end and an 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. (19) The tibial insert according to embodiment 18, wherein the flat portion of the third coronal curve is at an angle of approximately 6 degrees relative to the bottom surface of the tibial insert. (20) The tibial insert of embodiment 19, wherein the first coronal curve portion of the third coronal curve extends over an arc length ranging from 0.3 degrees to 0.9 degrees, and the second coronal curve portion of the third coronal curve extends over an arc length ranging from 16.4 degrees to 24.7 degrees.

[0147] (21) The tibial insert further includes an anterior sidewall and a posterior sidewall opposite the anterior sidewall, wherein a distance between the anterior sidewall and the posterior sidewall defines an anterior-posterior length of the tibial insert; The tibial insert of embodiment 1, wherein the medial articular surface includes a medial dwell point defining the most distal point of the medial articular surface, the medial dwell point being located approximately 63.3% of the anterior-posterior length from the anterior end. (22) The medial articular surface includes a medial dwell point defining a distal-most point of the medial articular surface; 2. The tibial insert of claim 1, wherein the arcuate articular path of the lateral articular surface is defined by a radius of curvature having an origin on the medial dwell point when viewed in a horizontal plane. (23) The tibial insert of embodiment 1 further includes a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism being configured to mate with a second portion of the locking mechanism located on a tibial base to secure the tibial insert to the tibial base. (24) A tibial insert, a lateral articular surface configured to articulate with a lateral condyle of a femoral component, the lateral articular surface including an arcuate articular path extending in an anterior-posterior direction, the arcuate articular path having a curvature that includes a subplanar portion when viewed in cross section, the subplanar portion defining a distal-most region of the lateral articular surface; a medial articular surface configured to articulate with the medial condyle of the femoral component, the medial articular surface being asymmetrically shaped relative to the lateral articular surface and including a medial dwell point defining a distal-most point of the medial condylar surface, the medial dwell point being located on the medial condylar surface between (i) a first imaginary medial-lateral bisector of the tibial insert that includes an anterior-posterior end of the flat portion of the sagittal curvature of the lateral articular surface and a second imaginary medial-lateral bisector of the tibial insert that includes an posterior-posterior end of the flat portion of the sagittal curvature of the lateral articular surface, and (ii) a medial articular surface located posterior to an anterior-posterior midpoint of the flat portion of the sagittal curvature of the lateral articular surface. (25) The tibial insert further includes an anterior sidewall and a posterior sidewall opposite the anterior sidewall, wherein a distance between the anterior sidewall and the posterior sidewall defines an anterior-posterior length of the tibial insert; 25. The tibial insert of claim 24, wherein the medial dwell point is located at approximately 63.3% of the anterior-posterior length from the anterior end.

[0148] (26) The tibial insert of embodiment 24, wherein the medial articular surface has a coronal concave curvature that is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point. (27) The tibial insert of embodiment 24, wherein the curvature of the arcuate joint path further includes a forward curved portion located anterior to the semi-planar portion and a plurality of rearward curved portions located posterior to the semi-planar portion when viewed in the cross section. (28) A tibial insert according to embodiment 27, wherein 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. (29) The tibial insert of embodiment 27, wherein the plurality of posterior curved portions include a first posterior curved portion adjacent to the rearmost end of the planar portion and a second posterior curved portion adjacent to the first posterior curved portion, and the radius of curvature of the first posterior curved portion is greater than the radius of curvature of the second posterior curved portion. (30) The tibial insert of embodiment 29, wherein 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.

[0149] (31) The tibial insert of embodiment 29, wherein the anterior curved portion extends over an arc length ranging from 33.5 degrees to 34.4 degrees, the first posterior curved portion extends over an arc length ranging from approximately 3.4 degrees, and the second posterior curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees. (32) The tibial insert of embodiment 24, wherein 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 dwell point is located on the sagittal concave curvature. (33) The tibial insert according to embodiment 32, wherein the plurality of curved portions include a first curved portion adjacent to the medial dwell point and extending posteriorly therefrom, and a second curved portion adjacent to the medial dwell point and extending anteriorly therefrom, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. (34) The tibial insert of embodiment 33, wherein the first curved portion extends over an arc length ranging from 15.9 degrees to 17.4 degrees and the second curved portion extends over approximately 5.2 degrees. (35) The tibial insert of embodiment 33, wherein the plurality of curved portions include a third curved portion adjacent to the second curved portion and extending anteriorly therefrom, a fourth curved portion adjacent to the third curved portion and extending anteriorly therefrom, and a fifth curved portion adjacent to the fourth curved portion and extending anteriorly therefrom, and wherein 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.

[0150] (36) The tibial insert of embodiment 35, wherein 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. (37) The tibial insert of embodiment 35, wherein the medial articular 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 medial articular surface at the medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other. (38) The tibial insert of embodiment 37, wherein the first coronal curve is defined by a coronal curve portion extending from the medial dwell point medially over an arc length ranging from 18.6 degrees to 26.8 degrees and from the medial dwell point laterally over approximately 25.0 degrees. (39) The tibial insert of embodiment 37, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second coronal curve is defined by a planar portion having a medial end and an 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. (40) The tibial insert according to embodiment 39, wherein the radius of curvature of the first coronal curve portion of the second coronal curve is smaller than the radius of curvature of the second coronal curve portion of the second coronal curve.

[0151] (41) The tibial insert of embodiment 40, wherein the first coronal curve of the second coronal curve portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curve portion of the second coronal curve extends over an arc length in the range of 20.1 degrees to 28.5 degrees. (42) The tibial insert of embodiment 39, wherein the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve is defined by a planar portion having a medial end and an 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. (43) The tibial insert according to embodiment 40, wherein the flat portion of the third coronal curve is at an angle of approximately 6 degrees relative to the bottom surface of the tibial insert. (44) The tibial insert of embodiment 43, wherein the first coronal curve portion of the third coronal curve extends over an arc length ranging from 0.3 degrees to 0.9 degrees, and the second coronal curve portion of the third coronal curve extends over an arc length ranging from 24.6 degrees to 16.5 degrees. (45) The tibial insert according to embodiment 24, wherein the arcuate joint path is defined by a radius of curvature having an origin on the medial dwell point when viewed in a horizontal plane.

[0152] (46) The tibial insert of embodiment 24, further comprising a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism being configured to mate with a second portion of the locking mechanism located on a tibial base to secure the tibial insert to the tibial base. (47) A tibial insert, a lateral articular surface configured to articulate with a lateral condyle of a femoral component, the lateral articular surface including an arcuate articular path extending in an anterior-posterior direction, a lateral dwell point defining a distal-most point on the lateral articular surface located on the arcuate articular path, and an anterior lateral lip, the superior-inferior distance between the lateral dwell point and an uppermost point of the anterior lateral lip defining a lip height of the anterior lateral lip; a medial articular surface configured to articulate with the medial condyle of the femoral component, the medial articular surface being asymmetrically shaped relative to the lateral articular surface, the medial articular surface including a medial dwell point defining a distal-most point on the medial articular surface, and an anterior medial lip, the superior-inferior distance between the medial dwell point and an uppermost point on the medial lateral lip defining a lip height of the anterior medial lip; (i) the lip height of the anterior medial lip is greater than the lip height of the anterior lateral lip; and (ii) a ratio of the lip height of the anterior medial lip to the anterior-posterior distance between the anterior sidewall of the medial articular surface and the posterior sidewall of the medial articular surface is in the range of 18.9% to 20.9%. (48) The tibial insert of embodiment 47, wherein the medial articular surface has a coronal concave curvature that is non-uniform anterior to the medial dwell point and uniform posterior to the medial dwell point. (49) The arcuate joint path has a curvature when viewed in cross section, including a semi-planar portion, a forward curved portion located in front of the planar portion, and a plurality of rearward curved portions located behind the planar portion; 48. The tibial insert of claim 47, wherein the lateral dwell point is located on the semi-flat portion. (50) A tibial insert according to embodiment 49, wherein 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.

[0153] (51) The tibial insert of embodiment 49, wherein the plurality of posterior curved portions include a first posterior curved portion adjacent to the rearmost end of the flat portion and a second posterior curved portion adjacent to the first posterior curved portion, and the radius of curvature of the first posterior curved portion is greater than the radius of curvature of the second posterior curved portion. (52) The tibial insert of embodiment 51, wherein 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. (53) The tibial insert of embodiment 5, wherein the anterior curved portion extends over an arc length ranging from 33.5 degrees to 34.4 degrees, the first posterior curved portion extends over an arc length ranging from approximately 3.4 degrees, and the second posterior curved portion extends over an arc length ranging from 13.2 degrees to 13.7 degrees. (54) The tibial insert of embodiment 47, wherein the medial articular surface includes a sagittal concave curve defined by a plurality of curved portions when viewed in the sagittal plane, and the medial dwell point is located on the sagittal concave curve. (55) The tibial insert of embodiment 54, wherein the plurality of curved portions include a first curved portion adjacent to the medial dwell point and extending posteriorly therefrom, and a second curved portion adjacent to the medial dwell point and extending anteriorly therefrom, and the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion.

[0154] (56) The tibial insert of embodiment 55, wherein the first curved portion extends over an arc length ranging from 15.9 degrees to 17.4 degrees and the second curved portion extends over approximately 5.2 degrees. (57) The tibial insert of embodiment 55, wherein the plurality of curved portions include a third curved portion adjacent to the second curved portion and extending anteriorly therefrom, a fourth curved portion adjacent to the third curved portion and extending anteriorly therefrom, and a fifth curved portion adjacent to the fourth curved portion and extending anteriorly therefrom, and wherein 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. (58) The tibial insert of embodiment 57, wherein 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. (59) The tibial insert of embodiment 57, wherein the medial articular 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 medial articular surface at the medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other. (60) The tibial insert of embodiment 59, wherein the first coronal curve is defined by a coronal curve portion extending from the medial dwell point medially over an arc length ranging from 18.6 to 26.8 degrees and from the medial dwell point laterally over approximately 25.0 degrees.

[0155] (61) The tibial insert of embodiment 59, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the second coronal curve is defined by a planar portion having a medial end and an 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. (62) The tibial insert according to embodiment 61, wherein the radius of curvature of the first coronal curve portion of the second coronal curve is smaller than the radius of curvature of the second coronal curve portion of the second coronal curve. (63) The tibial insert of embodiment 62, wherein the first coronal curve of the second coronal curve portion extends over an arc length in the range of 14.7 degrees to 15.7 degrees, and the second coronal curve portion of the second coronal curve extends over an arc length in the range of 20.1 degrees to 28.5 degrees. (64) The tibial insert of embodiment 61, wherein the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve is defined by a planar portion having a medial end and an 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. (65) The tibial insert according to embodiment 64, wherein the flat portion of the third coronal curve is at an angle of approximately 6 degrees relative to the bottom surface of the tibial insert.

[0156] (66) The tibial insert of embodiment 65, wherein the first coronal curve portion of the third coronal curve extends over an arc length in the range of 0.3 degrees to 0.9 degrees, and the second coronal curve portion of the third coronal curve extends over an arc length in the range of 24.6 degrees to 16.5 degrees. (67) The tibial insert further includes an anterior side and a posterior side opposite the anterior side, wherein a distance between the anterior side and the posterior side defines an anterior-posterior length of the tibial insert; 25. The tibial insert of claim 24, wherein the medial dwell point is located at approximately 63.3% of the anterior-posterior length from the anterior end. (68) The tibial insert of embodiment 24, wherein the arcuate articular path of the lateral articular surface is defined by a radius of curvature having an origin on the medial dwell point when viewed in a horizontal plane. (69) The tibial insert of embodiment 24, further comprising a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism being configured to mate with a second portion of the locking mechanism located on a tibial base to secure the tibial insert to the tibial base. (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 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 articular surface being asymmetrically shaped relative to the lateral articular surface and including a medial dwell point defining a distal-most point on the medial articular surface; the medial condyle contacts the medial dwell point at a first contact point on the first curved femoral surface portion at a first degree of flexion and contacts the medial dwell point at a second contact point on the first curved femoral surface portion at a second degree of flexion, the second contact point being posterior to the first contact point, and the second degree of flexion being greater than the first degree of flexion; The orthopedic knee prosthesis, wherein the medial articular surface includes a sagittal concave curvature having a first sagittal conformity with the medial condyle at a location anterior to a dwell point at the first degree of flexion and a second sagittal conformity with the medial condyle at the location anterior to the dwell point at the second degree of flexion, the second sagittal conformity being greater than the first sagittal conformity to reduce anterior translation of the medial condyle at the second degree of flexion.

[0157] (71) An orthopedic knee prosthesis as described in embodiment 70, wherein the medial condyle of the femoral component includes a sagittal convex curvature, and the sagittal compatibility between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. (72) The orthopedic knee prosthesis of embodiment 71, wherein the first degree of flexion is approximately 30 degrees. (73) The orthopedic knee prosthesis of 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 degree of flexion is greater at the medial dwell point of the medial articular surface than at the location on the medial articular surface anterior to the medial dwell point. (74) The orthopedic knee prosthesis of embodiment 73, wherein the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point. (75) The orthopedic knee prosthesis of embodiment 70, wherein the medial condyle and the medial articular surface are more conformable to one another than the lateral condyle and the lateral articular surface.

[0158] (76) An orthopedic knee prosthesis as described in 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 positioned in extension than when the femoral component is positioned in posterior flexion. (77) The lateral articular surface includes an arcuate articular path having a curvature when viewed in cross section, the arcuate articular path including a planar portion, an anterior curved portion located anterior to the planar portion, and a plurality of posterior curved portions located posterior to the planar portion; 71. An orthopedic knee prosthesis as described in embodiment 70, wherein the semi-planar portion defines the distal-most region of the lateral articular surface. (78) The orthopedic knee prosthesis of embodiment 77, wherein 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. (79) The sagittal concave curvature of the medial articular surface includes a plurality of curved portions when viewed in a sagittal plane, and the medial dwell 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 dwell point, a second curved portion adjacent to and extending forward from the inner dwell 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; An orthopedic knee prosthesis as described in embodiment 70, wherein 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 curvature of the fifth curved portion. (80) The orthopedic knee prosthesis of embodiment 79, wherein 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 dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other.

[0159] (81) The orthopedic knee prosthesis of embodiment 80, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curve being defined by a planar portion having a medial end and an 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, and the radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion. (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. 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. 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 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 a first flexion angle of about 5 degrees to a second flexion angle of about 65 degrees. 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. 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 selected from the range 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 from -0.010 to 0.00, and (ii) d is a coefficient value from -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 from -0.00015 to 0.00, the orthopedic knee prosthesis according to Embodiment 84.

[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 larger 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 degree of about 65 degrees to a second flexion degree 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, wherein 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 is defined by a continuously decreasing radius of curvature, and the second curved femoral surface portion is defined by a constant radius of curvature larger 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, 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 on the inner articular surface, a tibial insert, comprising: the medial condyle (i) contacts the medial dwell point at a first contact point on the first curved femoral surface portion at a first degree of flexion, the first contact point being defined by the posteriormost radius of curvature of the first curved femoral surface portion, and (ii) contacts the medial dwell point at a second contact point on the second curved femoral surface portion at a second degree of flexion greater than the first degree of flexion, 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 dwell point and the origin of the constant radius of curvature of the second curved femoral surface portion at the second degree of flexion is greater than the vertical distance between the medial dwell point and the origin of the most posterior radius of curvature of the first curved femoral surface portion at the first degree of flexion. (89) An orthopedic knee prosthesis as described in embodiment 88, wherein the medial condyle of the femoral component includes a sagittal convex curvature, the medial articular surface includes a sagittal concave curvature, and the sagittal compatibility between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. (90) The orthopedic knee prosthesis of embodiment 89, wherein the first degree of flexion is approximately 30 degrees.

[0161] (91) The orthopedic knee prosthesis of embodiment 88, wherein the medial articular surface includes a sagittal concave curvature, and at the medial dwell point, the sagittal concave curvature has a first sagittal conformity with the medial condyle at a first degree of flexion of the femoral component, and at a position on the medial articular surface anterior to the medial dwell point, the sagittal concave curvature has a second sagittal conformity with the medial condyle at the first degree of flexion, the second sagittal conformity being greater than the first sagittal conformity. (92) The orthopedic knee prosthesis of embodiment 91, wherein the medial articular surface includes a coronal concave curvature, and at the medial dwell point, the coronal concave curvature has a first coronal conformity with the medial condyle at the first degree of flexion, and at the location on the medial articular surface anterior to the medial dwell point, the coronal concave curvature has a second coronal conformity with the medial condyle at the first degree of flexion, and the second coronal conformity is greater than the first coronal conformity. (93) The orthopedic knee prosthesis of embodiment 92, wherein the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point. (94) The orthopedic knee prosthesis of embodiment 88, wherein the medial condyle and the medial articular surface are more conformable to each other than the lateral condyle and the lateral articular surface. (95) An orthopedic knee prosthesis as described in embodiment 88, 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 positioned in extension than when the femoral component is positioned in posterior flexion.

[0162] (96) The lateral articular surface includes an arcuate articular path having a curvature when viewed in cross section, the arcuate articular path including a semi-planar portion, a forward curved portion located anterior to the semi-planar portion, and a plurality of rearward curved portions located posterior to the planar portion; An orthopedic knee prosthesis as described in embodiment 88, wherein the planar portion defines the distal-most region of the lateral articular surface. (97) An orthopedic knee prosthesis as described in embodiment 96, wherein each posterior curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple posterior curved portions decrease posteriorly. (98) The sagittal concave curvature of the medial articular surface includes a plurality of curved portions when viewed in a sagittal plane, and the medial dwell 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 dwell point, a second curved portion adjacent to and extending forward from the inner dwell 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; An orthopedic knee prosthesis as described in embodiment 88, wherein 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 curvature of the fifth curved portion. (99) The orthopedic knee prosthesis of embodiment 98, wherein 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 dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other. (100) An orthopedic knee prosthesis as described in embodiment 99, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curve being 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.

[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 mate 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 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 a first flexion angle of about 5 degrees to a second flexion angle of about 65 degrees. 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 )) 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 selected from the range 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 from -0.010 to 0.00, and (ii) d is a coefficient value from -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 from -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 at 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 anterior-posterior 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 medial articular surface is asymmetrically shaped relative to the lateral articular surface and includes a medial dwell point defining the distal-most point of the medial condylar surface, the medial dwell point being located on the medial condylar surface between (i) a first imaginary medial-lateral bisector of the tibial insert that includes an anterior-posterior end of the flat portion of the sagittal curvature of the lateral articular surface and a second imaginary medial-lateral bisector of the tibial insert that includes an posterior-posterior end of the flat portion of the sagittal curvature of the lateral articular surface, and (ii) posterior to an anterior-posterior midpoint of the flat portion of the sagittal curvature of the lateral articular surface. (108) An orthopedic knee prosthesis as described in embodiment 107, wherein the medial condyle of the femoral component includes a sagittal convex curvature, the medial articular surface includes a sagittal concave curvature, and the sagittal compatibility between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension. (109) The orthopedic knee prosthesis of embodiment 108, wherein the first degree of flexion is approximately 30 degrees. (110) The orthopedic knee prosthesis of embodiment 107, wherein the medial articular surface includes a sagittal concave curvature, and at the medial dwell point, the sagittal concave curvature has a first sagittal conformity with the medial condyle at a first degree of flexion of the femoral component, and at a position on the medial articular surface anterior to the medial dwell point, the sagittal concave curvature has a second sagittal conformity with the medial condyle at the first degree of flexion, the second sagittal conformity being greater than the first sagittal conformity.

[0165] (111) The orthopedic knee prosthesis of embodiment 110, wherein the medial articular surface includes a coronal concave curvature, and at the medial dwell point, the coronal concave curvature has a first coronal conformity with the medial condyle at the first degree of flexion, and at the location on the medial articular surface anterior to the medial dwell point, the coronal concave curvature has a second coronal conformity with the medial condyle at the first degree of flexion, and the second coronal conformity is greater than the first coronal conformity. (112) The orthopedic knee prosthesis of embodiment 111, wherein the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point. (113) An orthopedic knee prosthesis as described in embodiment 107, 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 positioned in extension than when the femoral component is positioned in posterior flexion. (114) The arcuate articular path of the lateral articular surface has a curvature when viewed in cross section, including a semi-planar portion, a forward curved portion located anterior to the planar portion, and a plurality of rearward curved portions located posterior to the planar portion; An orthopedic knee prosthesis as described in embodiment 107, wherein the semi-planar portion defines the distal-most region of the lateral articular surface. (115) An orthopedic knee prosthesis as described in embodiment 114, wherein each posterior curved portion is defined by a corresponding radius of curvature, and the radii of curvature of the multiple posterior curved portions decrease posteriorly.

[0166] (116) The sagittal concave curvature of the medial articular surface includes a plurality of curved portions when viewed in a sagittal plane, and the medial dwell 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 dwell point, a second curved portion adjacent to and extending forward from the inner dwell 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; An orthopedic knee prosthesis as described in embodiment 107, wherein 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 curvature of the fifth curved portion. (117) The orthopedic knee prosthesis of embodiment 116, wherein 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 dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature are different from each other. (118) An orthopedic knee prosthesis as described in embodiment 117, wherein the second coronal curve intersects the sagittal concave curvature of the medial articular surface at the most distal point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curve being defined by a planar portion having a medial end and an 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, and the radius of curvature of the first coronal curved portion is smaller than the radius of curvature of the second coronal curved portion. (119) The orthopedic knee prosthesis of embodiment 118, wherein the third coronal curve intersects the sagittal concave curvature of the medial articular surface at the anterior-most point of the fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, and the third coronal curve is defined by a planar portion having a medial end and an 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. (120) The orthopedic knee prosthesis of embodiment 107, wherein the tibial insert further includes a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism being configured to mate with a second portion of the locking mechanism located on a tibial base to secure the tibial insert to the tibial base.

[0167] (121) The distal-most point of the femoral articular surface defines 0 degrees of flexion when the femoral component is in extension; An orthopedic knee prosthesis as described in embodiment 107, wherein the first curved femoral surface portion extends from a first degree of flexion of approximately 5 degrees to a second degree of flexion of approximately 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, each line having a length defined by the following polynomial: r θ =(a+(b * θ)+(c * θ 2 )+(d * θ 3 ))、 In the formula, r θ is the length of a line defining a 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 −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) An orthopedic knee prosthesis as described in embodiment 122, wherein the plurality of curved femoral surface portions includes a second curved femoral surface portion adjacent to and posterior to the first curved femoral portion, the second curved femoral surface portion being defined by a constant radius of curvature that is greater than the radius of curvature of the most posterior portion of the first curved femoral surface portion. (124) The orthopedic knee prosthesis of embodiment 123, wherein the second curved femoral surface portion extends from a first degree of flexion of approximately 65 degrees to a second degree of flexion of approximately 90 degrees.

Claims

1. 1. An orthopedic knee prosthesis comprising: 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 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 articular surface being asymmetrically shaped relative to the lateral articular surface and including a medial dwell point defining a distal-most point on the medial articular surface; the medial condyle contacts the medial dwell point at a first contact point on the first curved femoral surface portion at a first degree of flexion and contacts the medial dwell point at a second contact point on the first curved femoral surface portion at a second degree of flexion, the second contact point being posterior to the first contact point, and the second degree of flexion being greater than the first degree of flexion; the medial articular surface includes a sagittal concave curvature having a first sagittal conformity with the medial condyle at a location anterior to a dwell point at the first degree of flexion and a second sagittal conformity with the medial condyle at the location anterior to the dwell point at the second degree of flexion, the second sagittal conformity being greater than the first sagittal conformity to reduce anterior translation of the medial condyle at the second degree of flexion.

2. 2. The orthopaedic knee prosthesis of claim 1, wherein the medial condyle of the femoral component includes a sagittal convex curvature, and wherein a sagittal conformity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension.

3. The orthopaedic knee prosthesis of claim 2 , wherein the first degree of flexion is approximately 30 degrees.

4. 2. The orthopaedic knee prosthesis of claim 1, wherein the medial articular surface includes a coronal concave curvature, and wherein a coronal conformity between the coronal concave curvature and the medial condyle at the degree of flexion is greater at the medial dwell point of the medial articular surface than at the location on the medial articular surface anterior to the medial dwell point.

5. The orthopaedic knee prosthesis of claim 4 , wherein the medial articular surface is uneven anterior to the medial dwell point and uniform posterior to the medial dwell point.

6. The orthopaedic knee prosthesis of claim 1 , wherein the medial condyle and the medial articular surface are more conforming to one another than the lateral condyle and the lateral articular surface.

7. 2. The orthopaedic knee prosthesis of claim 1, wherein the medial articular surface includes a coronal concave curvature, and wherein a coronal conformity between the coronal concave curvature and the medial condyle is greater when the femoral component is positioned in extension than when the femoral component is positioned in later flexion.

8. the lateral articular surface includes an arcuate articular path having a curvature when viewed in cross section, the arcuate articular path including a planar portion, an anterior curved portion anterior to the planar portion, and a plurality of posterior curved portions posterior to the planar portion; The orthopaedic knee prosthesis of claim 1 , wherein the sub-planar portion defines a distal-most region of the lateral articular surface.

9. The orthopaedic knee prosthesis of claim 8 , wherein each posterior curved portion is defined by a corresponding radius of curvature, the radii of curvature of the plurality of posterior curved portions decreasing posteriorly.

10. the sagittal concave curvature of the medial articular surface includes a plurality of curved portions when viewed in a sagittal plane, and the medial dwell 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 dwell point, a second curved portion adjacent to and extending forward from the inner dwell 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; 2. The orthopaedic knee prosthesis of claim 1, wherein a radius of curvature of the first curved portion is greater than a radius of curvature of the second curved portion, and a radius of curvature of the third curved portion is less than the radius of curvature of the second curved portion, less than a radius of curvature of the fourth curved portion, and less than a radius of curvature of the fifth curved portion.

11. 11. The orthopedic knee prosthesis of claim 10, wherein the medial articular surface includes a coronal concave curvature defined by a plurality of coronal curvatures, including a first coronal curvature intersecting the sagittal concave curvature of the medial articular surface at the medial dwell point, a second coronal curvature located anterior to the first coronal curvature, and a third coronal curvature located anterior to the second coronal curvature, each of the first coronal curvature, the second coronal curvature, and the third coronal curvature being different from one another.

12. 12. The orthopedic knee prosthesis of claim 11, wherein the second coronal curvature intersects the sagittal concave curvature of the medial articular surface at an anterior-most point of the third curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the second coronal curvature being 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, wherein a radius of curvature of the first coronal curved portion is smaller than a radius of curvature of the second coronal curved portion.

13. 13. The orthopedic knee prosthesis of claim 12, wherein the third coronal curve intersects the sagittal concave curvature of the medial articular surface at an anterior-most point of the fourth curved portion of the plurality of curved portions defining the sagittal concave curvature of the medial articular surface, the third coronal curve being 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.

14. 2. The orthopaedic knee prosthesis of claim 1, wherein the tibial insert further includes a first portion of a locking mechanism located on a bottom surface of the tibial insert, the first portion of the locking mechanism configured to mate with a second portion of the locking mechanism located on a tibial base to secure the tibial insert to the tibial base.

15. a distal-most point of the femoral articular surface when the femoral component is in extension defines 0 degrees of flexion; The orthopaedic knee prosthesis of claim 1 , wherein the first curved femoral surface portion extends from a first degree of flexion of approximately 5 degrees to a second degree of flexion of approximately 65 degrees.

16. 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 having a length defined by the following polynomial: r θ =(a+(b) ＊ θ)+(c) ＊ i ２ )+(T ＊ i ３ )) In the formula, r θ is the length of a line defining a point on said 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 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 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 between −0.010 and 0.00, and (ii) d is a coefficient value between −0.00015 and 0.00; 16. The orthopaedic knee prosthesis of claim 15, wherein 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 from −0.00015 to 0.

00.

17. 17. The orthopaedic knee prosthesis of claim 16, wherein the plurality of curved femoral surface portions includes a second curved femoral surface portion adjacent and posterior to the first curved femoral portion, the second curved femoral surface portion being defined by a constant radius of curvature that is greater than the radius of curvature of a posteriormost portion of the first curved femoral surface portion.

18. 18. The orthopaedic knee prosthesis of claim 17, wherein the second curved femoral surface portion extends from a first degree of flexion of about 65 degrees to a second degree of flexion of about 90 degrees.

19. 1. An orthopedic knee prosthesis comprising: 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 and posterior to 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 that is greater than the radius of curvature of a most posterior portion of the first curved femoral surface portion; 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 articular surface being asymmetrically shaped relative to the lateral articular surface and including a medial dwell point defining a distal-most point on the medial articular surface; the medial condyle (i) contacts the medial dwell point at a first contact point on the first curved femoral surface portion at a first degree of flexion, the first contact point being defined by the posteriormost radius of curvature of the first curved femoral surface portion, and (ii) contacts the medial dwell point at a second contact point on the second curved femoral surface portion at a second degree of flexion greater than the first degree of flexion, 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 dwell point and the origin of the constant radius of curvature of the second curved femoral surface portion at the second degree of flexion is greater than the vertical distance between the medial dwell point and the origin of the most posterior radius of curvature of the first curved femoral surface portion at the first degree of flexion.

20. 20. The orthopaedic knee prosthesis of claim 19, wherein the medial condyle of the femoral component includes a sagittal convex curvature, the medial articular surface includes a sagittal concave curvature, and a sagittal conformity between the sagittal concave curvature of the medial articular surface and the sagittal concave curvature of the medial condyle is greater in a first degree of flexion of the femoral condyle than in extension.

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