An advisory panel for the U.S. Food & Drug Administration (FDA) began a highly-anticipated meeting yesterday to discuss the safety of metal-on-metal hip implants. Among other things, the panel of outside experts is being asked to make recommendations regarding the best practices for monitoring patients with metal-on-metal hip replacements. However, according to a report in The Wall Street Journal, the discussion so far indicates that panel may struggle to make recommendations given the shear number of metal-on-metal hip implants on the market, and conflicting data about their risks.
The panel has yet to vote on any recommendations, and begins a second day of deliberations today.
According to The Wall Street Journal, metal-on-metal hip replacement devices are marketed by a number of companies, including Johnson & Johnson’s DePuy Orthopaedics unit, Wright Medical Group, Inc., Biomet Inc., Zimmer Holdings Inc., Smith & Nephew PLC, and Encore Medical L.P. For the most part, all-metal hips used in total hip replacement are eligible for the FDA’s 510(k) clearance process, which does not require human testing if it can be shown a device is substantially similar to a predicate product. However, some metal-on-metal hip implants, including those that include major design modifications and devices used in hip resurfacing, do require additional testing.
When metal-on-metal hip implants were first brought to market nearly a decade ago, it was thought that they would be superior to devices made from plastic or ceramic. As we’ve reported previously, concerns about metal-on-metal hip implants peaked with the 2010 worldwide recall of DePuy Orthopaedics ASR hip implant devices, which were failing in about 12 percent of patients within just five years of implantation. Since then, a number of studies have pointed to significant problems with metal-on-metal hip implants. Last week, the FDA revealed that it had received 16,800 negative event reports involving metal hips between 2000 and 2011. Of those, more than 14,000 involved revision surgeries, in which a defective implant was removed.
According to the Journal, during yesterday’s session, advisors discussed the notion that there might be more problems with metal-on-metal hip implants that have a larger component, called the femoral head, than smaller components.
“Could it be the size of the head when we are attributing all the problems to metal?” said Raj Rao, a panel member from the orthopedic surgery department of the Medical College of Wisconsin.
“I don’t believe the failure mechanism of these devices is the same,” said Edward Cheng, a panelist from the University of Minnesota Medical School and Cancer Center.
The FDA panel will wrap up the today. Before it concludes, the panel will make recommendations about which types of patients would benefit the most from metal implants as well those who shouldn’t get them, and whether additional warnings and other information is needed for metal hip systems. According to the Journal, the panel has not been asked to recommend if the devices should undergo more extensive testing, or be subjected to additional regulation.