Wear, creep, and frictional heat of femoral implant articulating surfaces and the effect on long-term performance--Part I, A review.

Creep and wear of articulating reconstructed joints is a complex process, resulting in adverse tissue response, decreased range of motion, and eventual revision. As improvements are made in the design and surgical techniques of reconstructed joints, the long-term performance of the articulating system and materials becomes more important, particularly for younger, heavier, and more active patients. One aspect previously ignored in the long-term performance of articulating systems is the tendency for these systems to generate heat during articulation, particularly for extended periods of relatively strenuous activity. The present study reviews the various aspects of joint lubrication, friction, wear, and overall system performance. Local heating can increase the creep, wear, and oxidation degradation of UHMWPE, thus, specific attention is given to the effect that heat generation can have on long-term performance of these systems. Because of the complexity of this issue, the treatment of these various performance aspects is divided into two parts. The present part, Part I, reviews the various aspects of articulation performance. Part II presents results of friction, heating, and torque testing of various metal and ceramic hip systems. Criteria for frictional heating is also presented, along with discussion related to the various heat transfer mechanisms involved with heat dissipation.