Hip resurfacing unsuitable for women

By Lynda Williams, Senior medwireNews Reporter

Metal-on-metal resurfacing for osteoarthritis should be used only in men with a large femoral head, UK researchers believe.

Ashley Blom (University of Bristol) and co-workers make the recommendation after examining data from the National Joint Registry for England and Wales for 434,560 primary total hip replacements (THRs) performed between 2003 and 2011, including 31,932 resurfacing procedures.The average patient age was 54 years.

The 5-year revision rate for a 55-year-old man was predicted to be 4.1% for a 46 mm resurfacing head, compared with 2.6% for a 54 mm resurfacing head, and 1.9% for a 28 mm cemented metal-on-polyethylene stemmed THR.

Of note, just 23% of men undergoing resurfacing had a head size of 54 mm or greater.

"We would suggest that for orthopaedic surgeons, the decision to undertake resurfacing procedures in men needs to be made carefully," Blom et al write.

"Because femoral head size is determined by patient anatomy, we recommend that preoperative measurement is used to establish suitability for resurfacing."

For a 55-year-old women, the predicted 5-year rate for revision surgery was significantly higher after a 42 mm or 46 mm resurfacing head than for a 28 mm cemented metal-on-polyethylene stemmed total hip replacement, at 8.3%, 6.1%, and 1.5%, respectively.

Noting that the increased revision rate for resurfacing was elevated in women, even when compared with men with the same sized femoral head, the researchers suggest that this may be due to an increased risk for osteoporotic femoral neck fracture or predisposition to metal debris.

"In view of these findings, we recommend that resurfacing procedures are not undertaken in women," Blom et al emphasize.

Writing in The Lancet, the team notes that "neither stemmed metal-on-metal nor hip resurfacing has proven to be the solution for younger patients requiring THR. Therefore, other solutions such as metaphyseal bearing implants and novel bearings such as ceramic-on-metal and new polyethylene are being explored.

"We need to learn the lessons from resurfacing and stemmed metal-on-metal when introducing these new technologies," the researchers conclude.

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