Hip prosthesis. The femur side hip prosthesis includes both a ball and socket bearing and another (secondary) bearing system which facilitates motion of the type which is primarily in the forward and backward swinging of the leg. In certain embodiments of the invention, the secondary bearing system includes needle bearings and thrust bearings. That secondary bearing system lessens the motion of the ball and socket joint required during common activities such as walking. Certain embodiments of the invention include a modular connection between the stem for placement within the femur and the assembly that includes the secondary bearing.