The Food and Drug Administration (FDA) recently announced plans to hold a two-day expert advisory panel meeting in June to address mounting concerns about the safety of metal-on-metal hip implants. Hip replacement surgery is a common surgical procedure intended to provide increased patient mobility and alleviate pain associated with joint problems, including arthritis. According to the British Medical Journal, approximately 270,000 hip replacements are performed each year in the United States, accounting for nearly 40 percent of all joint replacements. There are currently four device options for total hip replacement, including metal-on-polyethylene, ceramic-on-polyethylene, metal-on-metal, and ceramic-on-ceramic.
Although all artificial hip replacement systems have risks related to implant or material wear, metal-on-metal hip implant systems have unique risks. In May of 2011, the FDA issued an order requiring all manufacturers of metal-on-metal hip implants to conduct post-market surveillance studies to collect more safety data on these devices, including data linking metal-on-metal hip implants to high concentrations of metal ions in the bloodstream. A recent study noted an increased failure rate associated with metal-on-metal hip implants in comparison with systems that use other materials. Another study reported that approximately 6 percent of people with metal-on-metal hip implants require additional surgery to replace or repair the implant after five years, compared with 1.7 to 2.3 percent of people who had ceramic or plastic systems.
During the expert review, panel members will discuss the failure rates and modes, metal ion testing, imaging methods, local and systemic complications, patient risk factors, and considerations for follow-up after surgery associated with metal-on-metal hip implant systems. The FDA will use the information gathered from the advisory panel meeting to decide whether to impose new, more rigorous testing and premarket review requirements on manufacturers of metal-on-metal hip implants.