June 18, 2014 - A 2011 report showed twice the number of revisions for metal-on-metal hip implants than for other types, including ceramic, polyethylene and metal-on-plastic. Surgeons began realizing that the all-metal hip implants were responsible for fretting, corrosion and the release of cobalt and chromium ions into the body.

In 1976 medical devices were added to the Food, Drug and Cosmetic Act, placing metal hip implants under FDA regulation. At this time metal-on-metal hip implants were categorized under a Class III or “high risk,” category. Nonetheless, the FDA made the determination to allow regulation of hip implant devices through the 510(k) fast track approval process. Metal-on-metal hip implants were not widely used during the next twenty years, however by the late 1980’s, second-generation metal hip implant designs had been introduced.