Alternative Bearing Surfaces in THR Devices Updated 4/8/08 William J. Hozack, MD Fabio Orozco, MD
Total hip arthroplasty (THA) is very successful when it comes to pain control and the restoration of function and the ability to walk. The most common bearing surface used in THA is polyethylene-on-metal. However, nowadays, with young and more active patients undergoing the procedure, other bearing surfaces such as metal-on-metal and ceramic-on-ceramic have been proposed as an alternative to metal-on-polyethylene as a technical solution to the need for reducing wear debris production and subsequent osteolysis leading to surgical revision. Some of the recent clinical results and wear debris consequences with these bearing surfaces were presented at the American Academy of Orthopaedic Surgeons 69th Annual Meeting and are summarized here…
In addition to the “classic” metal-on-polyethylene bearing surfaces used in THA, metal-on-metal and ceramic-on-ceramic bearings have become increasingly popular over the last few years. Metal-on-metal THA appears to have good clinical results and a very low rate of wear, but high blood levels of cobalt and chromium particles have been detected in patients using these devices. Nevertheless, the toxicologic importance and carcinogenic effect of trace metal elevations has not been established. Long-term prospective studies are needed to determine the risk of this implants as a potential cause of cobalt and chromium toxicity. Ceramic-on-ceramic bearings appear to be a safe option for young and active patients, demonstrating a very low wear rate and good clinical results. However, additional long-term studies are needed in order to completely elucidate the role of this type of articulation in THA.