A comparative study of the performance of metallic and ceramic femoral head components in total replacement hip joints

Arthroplasty represents an outstanding twentieth century achievement in orthopaedic surgery. However, in recent years polyethylene wear debris has been linked to the loosening process in implants and there is considerable interest in reducing the severity of wear through the introduction of improved materials and alternative designs of total replacements joints. During the past twenty years or so, ceramic components have been introduced, either as ceramic-on-ceramic or as ceramic-on-polymer combinations of sliding pairs of materials and in this paper a tribological appraisal is made of the performance of the latter combination in relation to the long established metal-on-polymer arrangement. The basic mechanisms of wear in total replacement joints are considered and attention is drawn to the role of creep in determining the initial penetration of the femoral head into the polyethylene acetabular cup. Laboratory and clinical studies of the tribological characteristics of current forms of implants are then reviewed.