Knee joint prosthesis with patellar-femoral contact

Claim 1

A knee joint prosthesis comprising a femoral component, a tibial component, coupling means connecting said femoral and tibial components for movement relative to each other, said coupling means including a pair of spaced substantially spherically curved condyle runners, a femoral attaching means in the top of the femoral component, the tibial component having a base, tibial connecting means on the bottom of the base, the coupling means also including a pair of spheriodally curved spaced parallel concave shoes on the base having upper surfaces intimately mating with the condyle runners for smooth relatively sliding movement between them, a pair of broadly inclined and smoothly merging anterior and superior extensions of the condyle runners on the femoral component, the extensions smoothly merging with each other to form a substantially circular arcuate trough disposed midbetween and parallel to the condyl runners, the trough having a center of curvature slightly posterior and somewhat superior to the center of movement of the femoral component relative to the tibial component, a patellar component, the posterior portion of the patellar component having a concave arcuate ridge for substantially matching the circular trough, the patellar component having a pair of bearing facets on both sides of the ridge which substantially match the lateral sides of the extensions whereby substantially total contact is maintained between the ridge and facets on the patellar component and the trough substantially throughout the entire range of movement of the prosthesis, the femoral and tibial components being made of a biocompatible metal, the bearing facets and ridge of the patellar component being made of a very strong and wear-resistant plastic material, and patellar attaching lugs on the anterior of the patellar component for connecting it to the patella.