Metal Hip Implants Face Tighter Controls

by Thomas M. Burton, Wall Street Journal

January 18, 2013

 

The Food and Drug Administration is studying whether several medical devices already on the market, such as electroconvulsive therapy devices for depression and emergency defibrillators, require additional evidence to prove they’re safe.

As part of that re-evaluation, the federal agency on Thursday proposed that companies making so-called metal-on-metal artificial hip joints produce medical evidence demonstrating their safety in order to stay on the market. Also, the FDA said, any new metal-on-metal hip products will require human clinical evidence to gain approval for marketing.

The metal-on-metal hips, of which there are estimated to be hundreds of thousands implanted in patients, have tended to fail and require replacement more quickly than some other artificial hip joints, according to recent medical research. One 2012 article in the British journal Lancet concluded that “metal-on-metal total hip replacement failed at high rates” and that such devices “give poor implant survival” compared with others made of polyethylene or ceramic materials.

In a safety advisory Thursday, the agency said patients with symptoms suggesting their devices aren’t functioning properly should be considered for testing of possible metal ions in their bloodstream. The agency said metal particles can lead to symptoms including skin rashes, neurological changes such as hearing and vision impairment, and psychological status changes including depression.

There have been recalls of hip joints in the past five years from Johnson & Johnson’s JNJ +0.07%DePuy unit, Zimmer Holdings Inc. ZMH +0.53%and of a Smith & Nephew SN.LN -0.07%PLC metal hip-implant component.

The FDA’s overall evaluation focuses on types of medical devices that were on the U.S. market when a 1976 law created a regulatory system for medical devices. New versions of some of these devices have been cleared for sale in the U.S. without clinical studies being required by the FDA. The agency has been evaluating whether more medical evidence may be required for 26 of these types of devices. It has made proposals for handling 18 of those 26, but eight others remain to be decided.

These include certain electroshock devices, orthopedic-surgery screws and emergency defibrillators of the sort used by paramedics. There have been reports over the years of some defibrillators failing to power up when needed to save a patient’s life.

William Maisel, deputy science director of the FDA’s device center, didn’t offer a time frame for a decision on the eight remaining devices, but said, “We consider this a very high priority.” The devices at issue got cleared through an abbreviated process, known as 510K, in which a company need only prove that a device is basically equivalent to another one already on the market—and needn’t conduct an extensive clinical study.

Diana Zuckerman, president of the National Research Center for Women & Families, said: “There are so many shortcuts at the FDA device center that they often take a shortcut and approve a product with minimal safety testing.”

Dr. Maisel responded: “For the vast majority of devices under 510K, the system allows an efficient and scientifically thorough evaluation. We acknowledge that, as with metal-on-metal hips, there are devices that would be better off with” clinical studies.

Write to Thomas M. Burton at tom.burton@wsj.com