“There is now compelling evidence that (metal-on-metal hip implants) fail at a higher rate than hip prostheses made of other materials; indeed, one type of metal-on-metal hip has a failure rate of nearly 50 percent at six years.”
The statement was made earlier this month in the New England Journal of Medicine by medical experts who reviewed data on hip replacement systems and determined that implants made from all-metal parts were more likely to fail than implants made from more traditional materials such as plastic or ceramic. Mounting evidence has prompted advisors to the Food and Drug Administration (FDA) to say the devices have little use on the market.
Metal-on-metal hip implants were designed to hold up better over time but they were found to be doing the opposite. In fact, not only were the devices failing at a higher rate than traditional implants, they were linked to a new problem – blood poisoning resulting from corroding metal parts that can send bits of chromium and cobalt into the bloodstream. The condition, known as metallosis, carries short-term symptoms such as headaches and fatigue, but the long-term problems have yet to be recognized. Some researchers say metallosis can damage DNA, which can lead to cancer.
Since 1999, nearly 17,000 problems with metal-on-metal hip implants have been reported to the Food and Drug Administration (FDA), and more than 12,000 of those complaints were reported last year alone. While reports were made about metal-on-metal hip systems from various manufacturers, the majority of problems were seen with one particular device – the ASR XL Acetabulator hip replacement system made by DePuy Orthopaedics, a subsidiary of Johnson & Johnson. In 2010, DePuy issued a worldwide recall of the ASR device.
Whether or not patients have the DePuy device, experts say that any patient with a metal-on-metal artificial hip should immediately report any pain or swelling to his surgeon and be evaluated with an X-ray and blood test for levels of metal. The panel also warned that current tests don’t accurately measure these levels.