By Toni Clarke
Jan 17 The U.S. Food and Drug Administration has issued a proposal calling on companies that make all-metal hip replacements to provide additional information proving they are safe and effective before being allowed to continue selling them.
The move follows years of concern within the medical community over the metal-on-metal implants, which the FDA said on Thursday can cause soft-tissue damage, potentially leading to further surgery to replace the devices.
All-metal hip implants were developed to be more durable than traditional implants but have become a major cause of concern after they were shown to fail at a higher rate than the traditional hip replacement devices. Traditional implants combine a ceramic or metal ball with a plastic socket.
The proposal will take time to implement - up to a year according to Dr. William Maisel, deputy director for science at the FDA's center for devices and radiological health. In the meantime, he said, physicians should only use metal-on-metal implants as a last resort.
"They should be rarely used, if at all, because there are good alternatives available," he said.
As many as 500,000 Americans are estimated to have been implanted with metal-on-metal hip replacements. Over the past few years an increasing body of evidence has shown that the devices may cause multiple health problems.
Johnson & Johnson, the largest manufacturer, withdrew its ASR hip system in 2010 after it was shown to fail at a higher-than-expected rate. It faces more than 2,000 lawsuits from patients claiming to have been harmed.
At their height, all-metal implants accounted for as many as 30 percent of artificial hips implanted in the United States each year, published reports show. That figure has dropped down to about 5 percent, Dr. Maisel said.
REGULATING MEDICAL DEVICES
Medical devices first became regulated in 1976 under an amendment to the Food, Drug and Cosmetic Act. The rules placed products into categories based on their perceived level of risk.
A low risk product such as a stethoscope would be required to meet a general set of good manufacturing standards but would not require much more to be allowed on the market.
A moderate risk product, such as a catheter, might have to meet additional sterilization standards, but would be cleared if it could show it was "substantially equivalent" to a product already on the market - a pathway known as 501(k).
A high risk product, such as implantable heart defibrillator or a breast implant, would have to be proven safe and effective in independent clinical studies before being allowed on the market.
In the wake of the amendment, the FDA was required to classify products that were already on the market and either call for additional clinical data for products considered high risk, such as all-metal hip implants, or downgrade such high-risk products to a lower classification.
But it has taken the FDA years to decide whether to make these calls. In the meantime, potentially high risk products have been allowed onto the market based on the pathway for moderate risk products. They have not required independent clinical trials.
The proposal issued by the FDA on Thursday confirms that all-metal implants should be considered high risk and it called for independent data showing they are safe and effective. The public has 30 days to comment. If the rule becomes final, companies will no longer be able to sell the products without conducting new clinical studies.
Five U.S. companies make all-metal implants: Biomet Inc, which was acquired by private equity consortium LVB Acquisition in 2007; Encore Medical, which became part of Reable Therapeutics and eventually merged with medical device maker DJO Global; Wright Medical Technology Inc ; Zimmer Holdings Inc and Johnson & Johnson's DePuy unit.
Lorie Gawreluk, a spokeswoman for DePuy, said that during the review process, "the company will continue to comply with all applicable regulations."
A spokesman for Biomet, Bill Kolter, said only that the company is studying the proposed rule. Wright Medical declined to comment. Zimmer was not immediately available to comment.
With wear, all-metal implants can shed metal where two components connect, potentially damaging bone and soft tissue surrounding the implant. ().
The FDA said it does not have enough data to specify the concentration of metal ions in a patient's body or blood necessary to produce adverse effects.
The reaction seemed to be specific to individual patients, the FDA said on its website.