Abstract
Introduction: A review of the concept of metal-on-metal bearings is presented.
Method: The material is based on a review of the literature and personal experience.
Results: The metal-on-metal bearing couple is enjoying a resurgence in clinical applications seen in both total hip and hip resurfacing technologies. The most significant advantage of a metal-on-metal implant is the improved wear characteristics seen both in vitro on wear simulators and in vivo with retrieved implants. All bearings have disadvantages and a metal-on-metal bearing is no exception. Concerns exist regarding the generation of metal ions seen in both the blood and urine of patients with metal-on-metal implants. These elevated metal ions have theoretical, although not proven, risks related to carcinogenic and biological concerns. In addition, concerns exist regarding hypersensitivity, increased incidence of instability and increased costs. As well, specific patient selection issues arise with metal-on-metal implants and with the current generation of implants only early and mid-term results are available, with no long-term series yet published.
Conclusions: Therefore, while a metal-on-metal bearing may be considered a viable alternative to either polyethylene or ceramic implants, outstanding and unresolved issues continue to exist.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
At least one of the authors is receiving or has received material benefits or support from a commercial source.
