According to a June 29, 2012 AP report, “Government health experts said Thursday there are few reasons to continue using metal-on-metal hip implants, amid growing evidence that the devices can break down early and expose patients to dangerous metallic particles.” The U.S. Food and Drug Administration (FDA) requested the 18-member Orthopaedic and Rehabilitation Devices Panel, convened to analyze the risks and benefits of metal-on-metal hip replacements, recommend guidelines for monitoring more than a half-million U.S. patients with the metal-on-metal hip devices.
Metal-on-metal hip implants have been a frequently used option for patients facing hip joint replacement. Metal-on-metal hip replacement systems were often marketed to younger more active patients, since the metal devices were believed to last longer than implants made from ceramic or plastic.
According to the FDA’s official medical device reporting system, known as the MAUDE database (Manufacturer and User Facility Device Experience), there were a total of 16,818 medical device reports regarding metal-on-metal total hip replacements (THR) submitted to the agency between the years 1992-2011.
According to a recent study released by the British Medical Journal, “Average failure rates at seven years are 11.8% for resurfacing and 13.6% for metal-on-metal hip replacement, although failure rates vary with the brand used. This compares with rates of 3.3% – 4.9% for hip implants made from other materials.” These results are based on data provided by the National Joint Registry for England and Wales. On February 28, 2012, the UK’s Medicines and Healthcare product Regulatory Agency (MHRA) released an updated medical device alert now advising that patients with metal-on-metal hip implants be monitored by their doctors annually for the lifetime of their device.
The Orthopaedic and Rehabilitation Devices Panel recommended that patients experiencing pain and other symptoms receive regular x-rays and blood testing for metal ions. However, many panel members raised concerns about the lack of standard diagnostic kits for testing metal levels. For asymptomatic patients, the panelists recommend surgeons monitor the implants on a yearly basis.
The FDA has requested that hip device manufacturers conduct long-term follow up studies of the metal-on-metal hip replacement systems currently marketed in the United States. During a public comment session, Diana Zuckerman, president of the National Research Center for Women & Families expressed concern about the time needed to conduct these additional studies. “Keeping these metal-on-metal hips on the market for the next five to 10 years while research is conducted is not ethical,” Zuckerman said. “If the companies want to sell metal-on-metal hips, they should be required to prove their safety first.”