Bearings of the future for total hip arthroplasty.

In the last decade or so, newer hip bearings such as ceramic-on-ceramic, metal-on-metal, and metal-on-highly cross-linked polyethylene were introduced into clinical practice in attempts to reduce the debris load released to the tissues after total hip arthroplasty. Present clinical evidence suggests that these newer bearings reduce both abrasive wear and the incidence of osteolysis at up to 10 years clinical follow-up. As further efforts to reduce abrasive wear may meet decreasing returns, we suggest that other bearing issues remain unresolved. These include mechanical failure, impingement or joint laxity, bearing noise, and stress shielding of supporting structures. We present a brief review of the current status of bearing technology and summarize potential areas for further research.