FDA Seeks Data on Risks of Metal Poisoning from Hip Replacements

Federal regulators are trying gather additional information about the potential risk of metal poisoning from the metal-on-metal hip replacements, as concerns continue to grow about the high levels of cobalt and chromium that may enter the bloodstream from the artificial hip implants. 

On May 6, the FDA ordered hip implant makers to conduct post market studies to gather data on the levels of metal in the blood of people who have received their hip implants and what health effects those implants might have. The agency sent a total of 145 post market surveillance orders to 21 different manufacturers, including DePuy Orthopaedics, Zimmer and Stryker.

Metal-on-metal hip replacements, which use cobalt and chromium in their construction, currently account for about one-third of the 250,000 hip replacements performed each year in the United States. However, in recent years, concerns over problems with metal-on-metal hip replacements has been growing.

As the metal hip replacement parts rub against each other, microscopic particles of cobalt and chromium may be shed into the body, which can result in metal poisoning, also known as metallosis. This may result in soft tissue damage, inflammatory reactions, bone loss, genetic damage, asceptic fibrosis, local necrosis or other problems that may lead to the need for a risky hip revision surgery.

Many metal-on-metal hip replacements have been linked to a high rate of early failure. In August 2010, a DePuy ASR hip recall was issued for more than 90,000 of the metal hip implants, after it was discovered that a higher-than-expected number were failing within a few years of surgery. Similar problems have been reported in connection with other metal-on-metal hip implants sold by other companies.

The American Academy of Orthopaedic Surgeons (AAOS) issued a warning in October 2010 about potential the risk of metal poisoning from hip replacements, indicating that patients and the medical community should be aware that pain months after hip surgery may be a sign of cobalt toxicity.

In February 2011, The FDA launched a new website in February 2011, which was designed to provide information about the risks associated with metal-on-metal hip replacements.

The FDA has now asked device manufacturers to obtain more information about the level at which the metal particles shed by hip replacements becomes dangerous, how much metal they actually shed and what the potential side effects of metallosis are.

Hundreds of individuals throughout the United States have already filed metal-on-metal hip replacement lawsuits over problems allegedly caused by metallosis or metal poisoning. All DePuy ASR hip lawsuits have been consolidated in federal court as part of an MDL, or multidistrict litigation. In addition, a petition is currently pending for a similar centralization order for a growing number of lawsuits over DePuy Pinnacle hip replacements, which is another metal-on-metal implant.