By BARRY MEIER (New York Times)
Under the order, producers of “metal-on-metal” hips will have to conduct studies of patients who received the device to determine, among other things, whether the implants are shedding high levels of metallic debris. Some patients have encountered that problem, including soft tissue damage that has disabled them.
In a telephone interview on Tuesday, Dr. William H. Maisel, the deputy director for science at the F.D.A.’s Center for Devices and Radiological Health, said the order marks the broadest use of the agency’s authority to conduct studies of devices after approval for sale. He also said that the F.D.A. wanted information about the entire category of implants, not any single manufacturer’s device.
“Our concern is the product, not about a manufacturer,” said Dr. Maisel.
The F.D.A. told about 20 manufacturers in a letter issued Friday that it was invoking a rule requiring postmarket studies in cases where an implant’s failure could have serious consequences.
The agency’s action could also prompt increased scrutiny of regulatory policies that allow implants like metal-on-metal hips to be approved for sale with little, if any, clinical testing in patients. In addition, the F.D.A.’s oversight of hip implants has lagged that in other countries where registries follow the failure rate of orthopedic implants in patients.
Metal-on-metal hips, in which the ball-and-socket components are made from metals like cobalt and chromium, accounted until relatively recently for about one-third of the estimated 250,000 hip replacement procedures preformed annually in the United States.
But over the last two years, the use of the implants has fallen off in part amid reports that they were prone to early failure and that some patients had developed serious health problems related to particles of metallic debris that are shed by the devices as they wear.
In March, for example, the British Orthopaedic Association, a professional medical group, reported that one model of all-metal hip made by a unit of Johnson & Johnson was projected to fail in one-half of the patients who received it within six years after implant. The company no longer sells the device, which was known as the ASR.
The British medical group also estimated, based on hospital data, that the early failure rate for all-metal hips made by other manufacturers was higher than expected, ranging from 12 to 15 percent within five years after implant. Artificial hips are designed to last for 15 years or more.
The British group said that the problems in the troubled devices were related to how certain components were joined.
Dr. Maisel, the F.D.A. official, said that the agency believed that all-metal hips provided benefits to patients. However, he added that there were significant enough medical concerns to warrant a broad review.
Dr. Maisel said that it was up to each manufacturer to determine how to conduct its studies. Under the agency rule, producers have 30 days to file a proposed plan with the F.D.A. He also said companies would be expected to collect information from patients who received the devices, including taking blood samples to determine the levels of metallic ion in their systems.
The companies are also being asked to determined how frequently the devices are failing.
“This is the largest group of studies that we have asked for,” for an approved class of devices, said Dr. Maisel.
Along with the DePuy division of Johnson & Johnson, other major producers of hip implants include Zimmer, Stryker, Biomet and Wright Medical.