The Food and Drug Administration is meeting with orthopedic experts today and Thursday to look into a growing body of worldwide evidence showing metal-on-metal hip devices have a higher failure rate than those made of plastic or ceramic.
"The FDA has been aware of some of these problems for three years and has made recommendations in the past, but I think what you'll see coming out of these meetings are more specific recommendations for follow-up care," says William Maisel, the FDA's chief scientist for medical devices.
The new recommendations will not be announced immediately, the agency says.
About 285,000 hip replacements are performed annually. An estimated 500,000 Americans have all-metal devices, which were believed to last longer than those made from other materials. In about the past 10 years, metal-on-metal implants and less invasive resurfacings often were chosen for younger, more active patients. From 2005 to 2006, the last year for which information is available, 32% of hip replacement surgeries were metal-on-metal devices.
But in the past few years, doctors have been seeing problems. Metal debris can break off when the joint's ball-and-socket pieces move against each other. The debris can cause pain and tissue damage, which can lead to complicated revision surgeries, get into the bloodstream, and in rare cases cause malignancies and heart, kidney, nerve and thyroid damage. Though the majority of people notice no problems, some studies show the all-metal devices require revisions at rates three to four times higher than those made from other materials and cause more problems in women.
The FDA says it will keep monitoring safety questions after the sessions, but it has no plans to ban all-metal devices, Maisel says.
"Doctors can still use them," he says, although "down the road that could come up." For now, he says, the FDA is focusing on improving follow-up care for patients having problems.
Still, some orthopedic surgeons told USA TODAY they refuse to use all-metal devices.
"They were a substitute for other components that were breaking down," says Joshua Jacobs, first vice president for the American Academy of Orthopaedic Surgeons. "But now the plastic components have improved, and there's really no need for using all metal components anymore. I don't use the all-metal components."
Tim Wright, director of biomechanics at the Hospital for Special Surgery in New York, says most of the facility's doctors also choose to use devices made of other materials.
Among current FDA recommendations: Doctors "may consider" blood tests, joint aspiration and imaging, and if patients have health changes, they should tell their physician they have a metal-on-metal implant or resurfacing.
The agency also will scrutinize actions taken by other countries that have more stringent follow-up recommendations. In the United Kingdom, for instance, the Medicines and Healthcare products and Regulatory Agency declared in February that patients with symptoms should have annual follow-up care for the rest of their lives rather than for five years. Also recommended were blood tests for metal levels and imaging tests of the joint and surrounding tissues. Acceptable levels of metals also are outlined with timetables for follow-up tests. The agency also advises when doctors should consider revision surgeries.
"We will be talking about recommending blood tests and have talked about them in the past," Maisel says, "but the blood tests aren't a perfect test yet, either. But we don't want people to think we haven't considered them."
A problem with requiring more frequent follow-ups only for patients experiencing problems is that the symptoms are not always noticed until the damage is done, Wright says .
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