The effect of clearance and wear on the contact pressure of metal on polyethylene hip prostheses

The aim of this paper is to determine the contact pressure, friction torque, and friction energy as a function of clearance and other parameters. The contact pressure is determined without imposing a priori a certain distribution law. The wear of the acetabular component modifies the relative clearance of the two bearing surfaces. This fact was observed at metal on polyethylene prostheses explanted during revision surgeries at our orthopaedy–traumatology hospital. For compliant contacts with small clearances, the Hertz theory is not applicable. Therefore, a new model, based on Hills contact theory is developed.