Abstract: A femoral component of a knee prosthesis includes a bearing surface defined by a smooth, continuous surface which in one embodiment is entirely formed by a series of three segments of surfaces of revolution, the respective shapes of which are generated by rotating a common generating curve around three separate generating axes at respective pairs of major generating radii and through respective angles of rotation. The central segment of the surfaces of revolution constantly maintains the substantially same contact configuration with the superior bearing surface of a bearing insert over a range extending from full extension (0.degree. of flexion) to at least 45.degree. of flexion and up to 105.degree. of flexion. The maintenance of the substantially same contact configuration ensures area, point or line contact between the articulating surfaces which reduces contact stress and wear in flexion.