HIGH PERFORMANCE KNEE PROSTHESIS

摘要

Knee prostheses featuring components that more faithfully replicate the structure and function of the human knee joint in order to provide, among other benefits: greater flexion of the knee in a more natural way by promoting or at least accommodating internal tibial rotation in a controlled way, replication of the natural screw home mechanism, and controlled articulation of the tibia and femur respective to each other in a more natural way. In a preferred embodiment, such prostheses include an insert component disposed between a femoral component and a tibial component, the insert component preferably featuring among other things a reversely contoured posterolateral bearing surface that helps impart internal rotation to the tibia as the knee flexes. Other surfaces can also be specially shaped to achieve similar results, preferably using iterative automated techniques that allow testing and iterative design taking into account a manageable set of major forces acting on the knee during normal functioning, together with information that is known about natural knee joint kinetics and kinematics.

主权项

1. A knee prosthesis, comprising:
one or more tibial components, comprising:
a post with a proximal end, a distal end, an anterior surface, and a posterior surface that is substantially opposite from the anterior surface, wherein the posterior surface includes a substantially straight segment along the posterior surface for a majority of a substantially proximal to distal length of the post, anda bearing surface coupled with the post at the distal end of the post; and a femoral component comprising:
a medial condylar section with a medial outer surface configured to engage the bearing surface of the one or more tibial components,a lateral condylar section with a lateral outer surface configured to engage the bearing surface of the one or more tibial components,wherein the medial condylar section and the lateral condylar section are disposed apart from one another to form an intercondylar notch, anda posterior cam that extends across the intercondylar notch between the medial condylar section and the lateral condylar section, wherein the posterior cam includes an anterior-distal surface with a first radius configured to contact the posterior surface of the post, a posterior-proximal surface substantially opposite from the anterior-distal surface and including a second radius, and an intervening surface between the posterior-proximal surface and the anterior-distal surface including a third radius configured to contact the posterior surface of the post, wherein proximal and distal relative to the one or more tibial components and relative to the femoral component refer to an orientation existing when the femoral component and the tibial component are aligned as the femoral component and the tibial component would be aligned if the femoral component were coupled with a femur and if the tibial component were coupled with a tibia and the femur and the tibia were oriented at approximately zero degrees of knee flexion-extension, wherein the femur is proximal and the tibia is distal, wherein the femoral component is configured such that the intervening surface of the posterior cam engages the substantially straight segment of the post of the one or more tibial components when the femoral component and the tibial component are aligned as the femoral component and the tibial component would be aligned if the femoral component were coupled with a femur and if the tibial component were coupled with a tibia and the femur and the tibia were oriented at approximately more than 90 degrees of knee flexion; and wherein the femoral component is configured such that the intervening surface of the posterior cam engages the substantially straight segment of the post of the one or more tibial components when the femoral component and the tibial component are aligned as the femoral component and the tibial component would be aligned if the femoral component were coupled with a femur and if the tibial component were coupled with a tibia and the femur and the tibia were oriented at deep flexion of the knee.