Patent ID: 9132014
Filing Date: 2015-09-15
Classification: A61F

Abstract:
1. A knee prosthesis that articulates between a substantially extended position and a flexed position, the substantially extended position defined as including full extension up to approximately 20° of knee flexion, the knee prosthesis comprising: a femoral component including a medial condyle having an inner surface and a lateral condyle having an inner surface, a distance between the inner surfaces of the medial and lateral condyles increasing as the knee prosthesis articulates from the substantially extended position to the flexed position, and a radius of curvature of one or both of the medial and lateral condyles decreasing in size in a posterior direction; and a tibial component including a medial surface configured for contact with at least a portion of the medial condyle of the femoral component, a lateral surface configured for contact with at least a portion of the lateral condyle of the femoral component, and a central eminence extending proximally from the tibial component and projecting between the medial and lateral condyles of the femoral component in both the substantially extended position and the flexed position, the central eminence having a proximal end spaced from the femoral component in both the substantially extended position and the flexed position, the central eminence having less contact with the inner surfaces of the medial and lateral condyles when the knee prosthesis is in the flexed position than when the knee prosthesis is in the substantially extended position such that the femoral and tibial components are more constrained, due to contact between the central eminence and the inner surfaces of the medial and lateral condyles, against movement relative to each other when the knee prosthesis is in the substantially extended position than when the knee prosthesis is in the flexed position, wherein the movement of the femoral and tibial components relative to each other includes a rotational movement of the femoral component relative to the tibial component about an axis that is medially offset from a center of the knee prosthesis, and the medial and lateral condyles of the femoral component and the medial and lateral surfaces of the tibial component continue to drive rotation of the femoral component relative to the tibial component about the axis as the knee prosthesis articulates from the substantially extended position to the flexed position.