New Studies Question Efficacy of Hip Resurfacing
BY LAUREN UZDIENSKI, JUNE 8, 2009
The promise of hip resurfacing seems to have faded somewhat with the publication of some new studies showing that outcomes for the procedure are similar to those associated with a traditional hip replacement. Additionally, the surgery has been found to have an increased revision rate for women.
A surgeon at Montreal's Maisonneuve-Rosemont Hospital says that hip resurfacing volumes are down from just two or three years ago. The same surgeon recently completed a study of 48 patients, half of whom had hip replacements, and the other half had resurfacings. Both groups reported comparable levels of activity, including gait speed and balance, at 12 months, which challenges assertions that patients who undergo hip resurfacing return to more rigorous activity. Two other studies, one consisting of 107 patients, affirmed these findings.
Women may also require revisions for a resurfacing procedure more often than for a traditional THA. Australian registry data shows that at five years, 5% of women under 55 with a resurfacing had undergone a revision, but less than 4% underwent a revision for a THA. This can be on account of smaller frames and lower bone densities, which can raise the risk of a fracture to the femoral neck (which is preserved in a resurfacing but not a THA.) For men, revision risk correlated with age; after 65, a revision for a resurfacing was more likely.
These outcomes raise questions on the efficacy of hip resurfacing, particularly considering the availability of harder, more durable surfaces for traditional hip replacements (ceramics are an example, though these have problems of their own). Companies and advocates for the procedure have always emphasized proper patient selection - the device is appropriate for young, active patients - and it is well-advertised that the surgery is a complex one with a daunting learning curve. Clinical data that is not particularly encouraging helps to emphasize the importance of patient selection and surgeon training and experience, though it also seems to have contributed to a waning enthusiasm surrounding the technology. Last year, Stryker announced slower-than-anticipated sales of the Cormet system it distributes in the U.S. and delayed additional orders for the device. Smith & Nephew has not released specific information on their Birmingham Hip's performance, though they report that in 2008, there was strong demand in the first half of the year that flattened out in the second. Additionally, Smith & Nephew said 1Q:09 U.S. hip performance was weighed down by weakening demand for the BHR, though at least part of that slowdown can be attributed to macroeconomic factors.
