Posterior Cructiate-Retaining Orthopaedic Knee Prosthesis Having Controlled Condylar Curvature

An orthopaedic knee prosthesis comprising:

• a femoral component having a condyle surface curved in the sagittal plane;
• and
• a tibial bearing having a bearing surface configured to articulate with the condyle surface of the femoral component,
• wherein the condyle surface (i) contacts the bearing surface at a first contact point on the condyle surface at a first degree of flexion, the first degree of flexion being less than about 30 degrees, (ii) contacts the bearing surface at a second contact point on the condyle surface at a second degree of flexion, the second degree of flexion being in the range of 45 degrees to 90 degrees, and (iii) contacts the bearing surface at a plurality of contact points between the first contact point and the second contact point when the femoral component is moved from the first degree of flexion to the second degree of flexion,
• wherein each contact point of the plurality of contact points is defined by a ray extending from a common origin to the respective contact point of the plurality of contact points, each ray having a length defined by the following polynomial equation:
• rθ=(a+(b*θ)+(c*θ2)+(d*θ3)),
• wherein rθ is the length of the ray defining a contact point 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,
• wherein 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,
• wherein 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, and
• 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 between −0.00015 and 0.00.