Knee prosthesis

A knee prosthesis comprising a femoral component for attachment to the femur and having a bearing surface which is cylindrically curved about medio-lateral axes without any curvature along the medio-lateral axes, said femoral component bearing surface including a first inferior cylindrically curved portion about a medio-lateral axis and also including a second posterior cylindrically curved portion about a medio-lateral axis, said second posterior curved portion being contiguous in a tangential relationship with and of relatively lesser curvature than said first curved portion, a tibial component for attachment to the tibia and having a concave bearing surface, and a meniscal component between the femoral and tibial components and having bearing surfaces complementary to said first curved portion of the bearing surface of the femoral component and to the bearing surface of the tibial component, the complementary bearing surfaces of the meniscal and tibial components being conical with straight line elements thereon extending from the vertices thereof such that relative axial rotation is possible between the tibial and meniscal components.