Poor Survival of Metal-on-Metal Total Hip Replacement

(HealthDay News) – For total hip replacement (THR), metal-on-metal stemmed articulations have poor survival rates compared with alternatives, such as metal-on-polyethylene and ceramic-on-ceramic.

To investigate whether stemmed metal-on-metal bearing surfaces lead to improved survival in THR, Alison J. Smith, from the University of Bristol in the United Kingdom, and colleagues analyzed data from the National Joint Registry of England and Wales on 402,051 primary hip replacements, 31,171 of which were stemmed metal-on-metal, undertaken between 2003–2011.

The researchers found high failure rates for metal-on-metal THR. Failure correlated with head size, with larger heads failing earlier (for men aged 60, cumulative incidence of revision at five years: 3.2% for 28mm vs 5.1% for 52mm). In younger women, the five-year revision rates were 6.1% for 46mm metal-on-metal vs 1.6% for 28mm metal-on-polyethylene. Large head size correlated with improved survival for ceramic-on-ceramic articulations (for men aged 60, five-year revision rate: 3.3% for 28mm vs 2% for 40mm).

“Metal-on-metal stemmed articulations give poor implant survival compared with other options and should not be implanted. All patients with these bearings should be carefully monitored, particularly young women implanted with large diameter heads,” the authors write.

One of the authors disclosed receiving royalties from DePuy for a cemented total hip prosthesis.

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