The FDA has asked 20 devicemakers, including Stryker, Zimmer and the embattled Johnson and Johnson, to investigate whether their hip implants raise the level of metal in patients' blood to dangerous levels. The agency, which is concerned about the metal-on-metal implants, made the request for the postmarket surveillance May 6. According to the agency's website, "there are some case reports in the literature of a small number of patients in which high levels of metal ions in the bloodstream may have caused other types of symptoms or illnesses elsewhere in the body, including effects on the heart, nervous system and thyroid gland."
J&J's DePuy Orthopaedics unit is one of the companies that has faced lawsuits arising from problems with the artificial hips. The FDA says metal debris from the implants can cause damage to the bone and tissue surrounding the implant and joint. Last month, the Senate Special Committee on Aging will hold a hearing titled "A Delicate Balance: FDA and the Reform of the Medical Device Process." The panel was examining the FDA's role in protecting patient safety as part of the medical device approval process and featured Katie Korgaokar, a Denver resident who received a DePuy ASR hip implant. She was one of the more than 90,000 patients affected by the DePuy hip recall.
The FDA "is aware of the public health questions regarding the safety of metal-on-metal total hip replacement systems," agency spokeswoman Karen Riley said in an e-mail to Bloomberg. "There is not enough scientific data to specify the concentration of metal ions in a patient's body necessary to produce adverse systemic effects."
In a telephone interview with the New York Times, William Maisel, the deputy director for science CDRH, said the order marks the broadest use of the agency's authority to conduct studies of devices after approval for sale. He added the FDA wanted data about the entire category of implants, not any single manufacturer's device.
DePuy "is seeking further clarification from the FDA and considering how to best meet the agency's requirements," Lorie Gawreluk, a spokeswoman, said in an e-mail to Bloomberg. Meanwhile a spokesman for Zimmer said his company was "working to understand the scope of the agency's request." A Stryker spokesman said in an email to the news service that the company doesn't make metal-on-metal implants and declined to comment further.