Posterior stabilized knee with varus-valgus constraint

摘要

A femoral component (12) of a knee prosthesis has spaced condyle surfaces (30,32) defining a notch (40) between them. The notch (40) defines an elongated cam housing (42) having an anterior cam (50) and a posterior cam (55) at opposite ends of the housing. The tibial component (14) of the knee prosthesis includes a platform (16) and a bearing (20) supported on the platform (16), the bearing (20) defining bearing surfaces (26,28) configured to articulate with the condyle surfaces (30,32). The tibial component (14) includes a spine (60) projecting superiorly from the bearing (20) that defines an anterior face (62) and a posterior face (64). The posterior face (64) and the posterior cam (55) define complementary curved surfaces configured for cooperative engagement when the femoral component (12) and the tibial component (14) are at a predetermined flexion angle. The cam housing (42) is configured to form a gap between the posterior cam (55) and the spine (60) when the knee is normally extended. In another feature, the spine (60) includes a stiffening pin (72) extending through it. <IMAGE>