Metal-on-Metal Hip Risks Lead FDA to Require PMA to Remain on Market

Federal regulators are requiring manufacturers of metal-on-metal hip replacements, which have been linked to reports of problems and premature failures, to place their devices through the full premarket approval process (PMA) to establish that they are safe and effective.

In a final rule issued today in the Federal Register, the FDA indicates that given the known risks certain devices must go through a PMA application process to remain on the market, or for new devices to be introduced.

Metal-on-metal hip replacements have been sold by a number of different manufacturers in recent years, featuring a metal femoral head that rotates within a metal acetabular cup.

Most of the devices were introduced through the controversial fast-track 510(k) approval process, which only required that the device be a “substantial equivalent” to an already existing device approved by the FDA. However, the snowball effect of the substantial equivalence test has allowed many devices now considered unreasonably dangerous and defective to be implanted in thousands of Americans.

Unlike other artificial hip designs, which typically feature metal-on-ceramic or metal-on-plastic, the metal-on-metal hips have been found to release microscopic metallic debris as the parts rub against each other. This has been linked to reports of loosening and failure, often within a few years after the artificial hip is implanted.

Two types of metal-on-metal total hip replacement devices will be impacted by the rule: the hip joint metal/metal semi-constrained with a cemented acetabular component and the hip joint metal-metal semi-constrained iwth an uncemented acetabular component.

All new metal hip replacements introduced by manufacturers must go through the full PMA process, and manufacturers of devices currently on the market must reapply by May 18 to continue to sell the devices.

In recent years, a number of hip recalls and problems have been associated with metal-on-metal designs, suggesting that the hips may be prone to loosen and fail due to the release of this microscopic debris. In addition, some concerns have been raised about the development of tumors and a potential risk of cancer that may be associated with the design.

Addressing those concerns, the FDA reclassified metal hip implants as Class III (high risk) medical devices. Now, they will have to fill out a premarket approval application which includes requirements that they prove the device is effective, provide “full reports of all nonclinical and clinical information from investigations and effectiveness of the device” and inform the FDA of any risks that are known or should be reasonably known by the manufacturer.

According to an FDA press release issued regarding the final order, there are five manufacturers who currently market metal-on-metal hips in the U.S. The FDA has required them to conduct postmarket surveillance studies of the devices they have on the market and all have submitted plans to do so.

Thousands of metal-on-metal hip replacement lawsuits have been filed in recent years throughout the U.S., alleging that the manufacturers failed to adequately research the design or warn about the large number of implants that were failing within a few years and requiring revision surgery.

Johnson & Johnson recently agreed to pay more than $2.4 billion to settle DePuy ASR hip lawsuits faced by their subsidiary, resolving about 8,000 cases brought by individuals who required revision surgery prior to August 2013. However, as devices continue to fail, it is expected that thousands of additional hip settlements will be paid by the manufacturer, as an estimated 90,000 implants were sold worldwide before the recall.

Similar lawsuits are pending against manufacturers of other metal-on-metal hip lawsuits, including the DePuy Pinnacle, Biomet Magnum, and the Wright Medical Conserve Cup .