Metal Hip Implant Revision Rate Unacceptably High Researchers SayMay 6, 2016
A study published online in BMJ Open found that the risk of failure and revision surgery with metal-on-metal hip implant patients is "unacceptably high". The researchers found that the elevated rates of complications may stem from the use of parts that were outside of stated manufacturing tolerances, Medscape reports.
"There is general acceptance that large diameter [MoM] total hip arthroplasty (THA) has not lived up to clinical expectations," the authors stated. "Although the use of MoM hip devices has declined dramatically in the past 5 years, hundreds of thousands remain in situ, with the long-term future uncertain.
Metal-on-metal hip implants have come under intense scrutiny over the past several years in light of high-profile recalls. The hip replacements are composed of all-metal surfaces, which can grind together and lead to a host of complications such as pain, inflammation, swelling and joint dislocation. A number of patients were forced to undergo revision surgery when the implant failed. High revision rates prompted the worldwide recall of DePuy's ASR metal-on-metal hip implant, bringing metal hip implant safety concerns to light in 2010.
The recent study was led by Dr. David Langton of University of North Tees in Stockton, UK. He and his colleagues looked at the progress of 243 women and 191 men who had metal-on-metal Pinnacle hip implants, which are manufactured by DePuy. The patients were followed for an average of 7.5 years after surgery; 71 hips needed to be surgically removed and replaced. "This device was found to have an unacceptably high revision rate," the authors said.
American Academy of Orthopaedic Surgeons spokesperson David Jevsevar, MD, MBA, told Medscape Medical News that even though the failure rate "does not change the approach to continuing surveillance on patients with MoM total hip arthroscopy, for patients with this implant system, it does provided [an implant] survival rate that can be shared with patients,"
Among devices that had been removed due to failure, signs of taper-junction failure (70%) were more common than signs of bearing failure (48%). The rate of failure tended to be higher in female patients, with 77.9 percent predicted to survive at 9 nine years compared to 91.4 percent for males.