Patent ID: 7413577
Filing Date: 2008-08-19
Classification: A61F

Abstract:
1. In a total stabilized knee prosthesis for implantation to replace a natural knee joint, the knee prosthesis having a femoral component including at least one condylar element with a condylar surface having a transverse axis of rotation extending transverse to a sagittal plane, and a tibial component including at least one articular surface configured for engagement with the condylar surface of the femoral component during articulation of the knee prosthesis about the transverse axis of rotation, with the condylar surface and the articular surface engaged along corresponding posterior aspects during deep flexion, the condylar surface and the articular surface being configured and dimensioned for enabling engagement between the condylar surface and the articular surface along a prescribed track having a predetermined curvature which enables relative rotational movement between the femoral component and the tibial component about a longitudinal axis of rotation during articulation about the transverse axis of rotation, the condylar surface and the articular surface including profile contour configurations in generally medial-lateral longitudinal planes, the condylar surface having an inner surface portion confronting the longitudinal axis of rotation, and the articular surface having an outer surface portion for engagement with the inner surface portion during articulation, and wherein a level of constraint against uncontrolled relative rotational movement and varus-valgus movements between the femoral component and the tibial component is provided by engagement of a post on one of the femoral component and the tibial component with a compartment in the other of the femoral component and the tibial component: an improvement wherein the inner surface portion and the outer surface portion are each flared outwardly, in a transverse direction away from the sagittal plane, along the posterior aspects of the condylar surface and the articular surface for providing an engagement between the profile contour configurations sufficient to establish a level of constraint against uncontrolled relative rotational movement between the femoral component and the tibial component about the longitudinal axis, thereby enabling a decrease in the level of constraint provided by the engagement between the post and the compartment during articulation through deep flexion.