U.K. Registry Data Confirm Metal-on-Metal Hip-Implant Problems

Metal-on-metal hip replacements — especially those with larger head sizes — fail at higher rates than other types of bearing surfaces, and the evidence is "unequivocal" according to a Lancet report.

Investigators evaluated registry data on over 400,000 total hip replacements of various types. They excluded ASR implants (a type of metal-on-metal implant that has been withdrawn from the market because of high failure rates).

Metal-on-metal implants had 5-year failure rates necessitating revision that were triple those of the other bearing types — roughly 6% versus 2%. Larger metal-on-metal head sizes were most prone to failure; ceramic-on-ceramic prostheses, however, showed better performance with larger head sizes.

A commentator says the registry data add to the evidence that the problem is not caused by a specific brand of metal-on-metal implant, but rather it is a class effect.

Lancet article (Free abstract)

Lancet comment (Subscription required)

Physician's First Watch coverage of recent BMJ report on metal-on-metal implants (Free)