Boehringer Mannheim Gmbh

James Caywood

Donald E McNulty

Richard R Van Zile

A knee prosthesis is provided including a tibial component having first and second generally concave bearing surfaces and a stabilizing post extending upwardly between the first and second bearing surfaces. The knee prosthesis also includes a femoral component having first and second spaced apart, convexly curved condyle bearing surfaces and a cam surface extending between the first and second bearing surfaces. The femoral component is articulatable with the tibial component between an extended position and a flexed position. The first and second femoral bearing surfaces engage the first and second tibial bearing surfaces, respectively, at first and second contact points. Between the extended position and about a 25.degree. flexion angle, the cam surface is spaced apart from a posterior side wall of the stabilizing post to permit movement of the femoral and tibial component as natural physiology dictates. As the knee prosthesis is flexed at about a 25.degree. flexion angle, the cam surface first engages the posterior side wall of the stabilizing post to control movement of the femoral component relative to the tibial component. Therefore, the stabilizing post engages the cam surface to control the position of the femoral component relative to the tibial component only upon flexion of the femoral and tibial component between about 25.degree. flexion and the flexed position.

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Warsaw, IN, United States of America

James Caywood