In a study published in this month’s Journal of Bone and Joint Surgery (British Volume), researchers found an overall 10-year survival rate of 94.5% with a metal-on-metal hip resurfacing system and noted the resurfacings were 1.4 times more likely to fail in women.
According to a British Editorial Society of Bone & Joint Surgery release, the findings were the result of an independent review of 230 consecutive Birmingham hip resurfacings (Smith & Nephew, Memphis) performed in 213 patients at a mean follow-up of 10.4 years. Of the cases, 11 hips underwent revision, six patients died of unrelated causes and 13 patients representing 16 hips were lost to follow-up.
When the results were compared for gender, the investigators found survival rates of 97.5% for men and 89.1% for women. Each millimeter increase in component size, the release noted, represented a 19% lower chance of failure.
The study patients had a mean Oxford hip score of 45, a UCLA activity score of 7.4 and patient satisfaction score of 1.4. The researchers found lysis in the femoral neck of eight hips, with acetabular lysis found in two hips. One of the hips, according to the release, displayed progressive radiological changes around the peg of the femoral component, with no evidence of progressive neck narrowing being found between the 5-year and 10-year marks.
“Our results confirm that [Birmingham hip resurfacing] BHR provides good functional outcome and durability for men, at a mean follow-up of 10 years,” the authors wrote in the abstract. “We are now reluctant to undertake hip resurfacing in women with this implant.”
- Coulter G, Young DA, Dalziel RE, Shimmin AJ. Birmingham hip resurfacing at a mean of 10 years: Results from an independent centre. J Bone Joint Surg (Br). 2012. doi: 10.1302/0301-620X.94B3.28185