One or both of the condyles in a femoral component for a partial or total knee prosthesis includes a J-curve with a plurality of distinct radii, such as 5 or more radii. The centers of the radii are arranged along an arcuate path extending anteroposteriorly so that successively larger radii are serially arranged along the arcuate path from the posterior side of the femoral component to the anterior side. The femoral component provides a high degree of stability throughout the range of motion of the knee prosthesis, and facilitates a close approximation to the motion of a natural knee.