Patent ID: 7326252

Claim:
A prosthesis for replacement of at least part of a knee joint in a leg of a patient, the leg including a femur, a tibia and a mechanical axis, the prosthesis comprising: (a) a femoral component adapted to fit on a distal end of the femur, the femoral component comprising: (i) a lateral condylar structure and a medial condylar structure, the lateral condylar structure defining a lateral condylar bearing surface and the medial condylar structure defining a medial condylar bearing surface; (ii) a posterior cam extending between the lateral condylar structure and the medial condylar structure; wherein the posterior cam is asymmetric such that a lateral portion of the posterior cam is larger than a medial portion of the posterior cam; and (iii) an anterior cam; and (b) an accommodation structure corresponding to a proximal end of the tibia, the accommodation structure configured to cooperate with the femoral component and comprising: (i) a raised portion adapted to cooperate with the anterior and posterior cams of the femoral component; (ii) a medial accommodation surface configured to cooperate with the medial condylar bearing surface; wherein the medial accommodation surface and the medial condylar bearing surface define a medial compartment; and (iii) a lateral accommodation surface configured to cooperate with the lateral condylar bearing surface; wherein the lateral accommodation surface and the lateral condylar bearing surface define a lateral compartment; wherein the medial and lateral compartments are asymmetric in a frontal plane of the prosthesis when the prosthesis is installed such that a line between points at which the lateral condylar bearing surface contacts the lateral accommodation surface and at which the medial condylar bearing surface contacts the medial accommodation surface is oriented at an angle that is not orthogonal to the mechanical axis of the leg; and wherein flexion of the prosthesis causes the lateral condylar bearing surface to migrate posteriorily on the lateral accommodation surface to cause the tibia to rotate interiorly with respect to the femur during flexion.