About half a million people in the United States have received metal-on-metal implants, but these artificial hips have become controversial in the past few years.
What is a Metal-on-Metal Hip Implant?
In the past, hip implants often used a combination of metal and plastic or ceramic. With a metal-on-metal hip replacement, all the parts are made of metal. When these all-metal implants were introduced, doctors thought that they would be more durable, and thus a better option for younger, more active patients. It was also thought that they would be less prone to dislocation.
Issues: Metal Particles and the Need for Corrective Surgery
The problem is, when the pieces rub together, the implant can start to shed small pieces of metal, usually cobalt and chromium ions. These tiny particles can then go into the bloodstream and affect the bone and tissue near the implant, which can cause pain, swelling and inflammation. In some cases, the side effects become so bothersome that patients undergo a corrective, or “revision” surgery to remove the failed implant. A higher than normal failure rate is one of the main reasons why some are skeptical about metal-on-metal hip replacements.
In August 2010, Johnson & Johnson’s DePuy Orthopaedics unit recalled about 93,000 metal hip devices around the world due to a high rate of failure, about 1 in every 8 patients according to the National Joint Registry. This global recall triggered a number of safety concerns and lawsuits – not just with Johnson & Johnson, but with all types of metal-on-metal hip replacements.
Implants Weren’t Tested
It may come as a surprise that to find out that your hip replacement wasn’t clinically tested before being sold. Metal-on-metal hips were approved through a fast-track process known as the 510(k). This lets manufacturers sell a new device without performing any clinical testing if they can show that it is similar enough to a product that’s already on the market. According to the U.S. Department of Health & Human Services, approval through 510(k) is used for 90 percent of the medical devices in the United States.
But for those who have suffered side effects from these devices, the lack of testing can be a frustrating discovery. Dwight Schrag, a Washington resident whose wife had to undergo revision surgery following painful complications from her hip implant, told the Associated Press “I am so furious they would use my wife as a lab rat, along with the other 500,000 people who don’t have a clue what is happening,”
About two weeks ago, an FDA advisory panel held a two-day meeting to discuss the pros and cons of metal hip replacements and listen to presentations from consumers, researchers, doctors and manufacturers. The group also talked about recommendations for patient care in the future. Unlike other regulatory agencies, the FDA has never issued any specific guidelines about how to treat patients who suffer side effects from metal-on-metal hips. The 18-member panel addressed this by urging the FDA to provide more information in order to help consumers and doctors. Among other things, panelists said that there should be stronger warning labels that mention the risk of metal ion debris and pseudotumors, which is a mass that looks like a tumor but is actually the result of inflamed tissue and fluid build-up. The panel also suggested imaging techniques such as X-rays and MRIs to better detect abnormalities in the tissue and bone.
Last week, Stryker Orthopaedics voluntarily recalled two types of metal-on-metal implants. The company said that the decision was based on “the potential for fretting and/or corrosion at or about the modular-neck junction, which may result in adverse local tissue reactions manifesting with pain and/or swelling”
What to Do?
While the prospect of a failing device inside your body sounds scary, it’s important to remember that these complications do not occur in all patients. If you do experience symptoms like pain, swelling or difficulty walking, or if you aren’t sure what type of hip replacement you have, it is always best to speak to your doctor or orthopedic surgeon.