There has been continued interest in the benefits and potential risks associated with various bearing surfaces in total hip replacement. Most of us are aware of reports of squeaking associated with some types of ceramic-on-ceramic hips. The etiology of this phenomenon is not clear but seems to be associated with multiple factors, including the type of prosthesis, the positioning of the implants, and patient-related factors. Metal-on-metal hip replacements have been associated with a hypersensitivity reaction which is a form of allergic reaction to the ions associated with metal-on-metal bearings. The incidence of this phenomenon is unknown but appears to be quite low, in the range of 1%. Many factors appear to be involved, including the type of metal that is used, the design of the implant, the positioning of the implants, and patient-specific factors that influence a person’s reaction to these ions. There have been several reports of decreased wear associated with ceramic-on-ceramic and metal-on-metal bearings. Because of concerns associated with these bearings, we will most likely see a rise in metal or ceramic on polyethylene bearing surfaces. Each one of these bearings has its associated pluses and minuses, and when considering a hip replacement, you should discuss these with your surgeon. If you are contemplating a surface replacement, at present there is no alternative to a metal-on-metal articulation which may further decrease the use of surface replacements for the treatment of osteoarthritis.
I’d be interested to hear your take on the latest news about metal-on-metal replacements. Seems that many surgeons are cutting back or stopping using that type of implant. Is this biased reporting or a real cause for concern?
Dear Pamela,
The New York article is a hit sensational. There is an incidence of allergic type reaction to metal-on-metal bearings. It seems low in the 1-2% range. Therefore some surgeons have cut back their use of these bearings. More research is ongoing.
Regards,
William Barrett