Metal-On-Metal Hip Implant?
The DePuy Pinnacle hip implant consists of a femoral stem attached to a metal head that rotates inside a titanium acetabular cup. The inside of the cup is lined with a plastic, ceramic or cobalt-chromium liner; the latter is branded as the “Ultamet.” When the Pinnacle is used with the Ultamet metal liner, it is known as a metal-on-metal hip implant.
Metal-on-metal total hip replacements were introduced for their supposed advantages over conventional devices, such as low rates of wear and increased stability. However, concerns about all-metal hip implants started to mount in 2010, when DePuy Orthopaedics issued a recall of its ASR hip devices, after it was found that they were failing in about 12 percent of patients within just five years of implantation. The U.S. Food & Drug Administration (FDA) began studying all-metal hip implants shortly after the DePuy ASR hip implant recall to determine if the devices are shedding dangerous levels of metal ions into patients’ surrounding tissue and blood streams.
Metal-on-metal hip implants were approved by the FDA through a process known as the 510(k). This clearance protocol does not require that manufacturers present clinical evidence to prove a device is safe or effective so long as they can show it is “substantially equivalent” to a previously approved device, referred to as a “predicate.” DePuy managed to gain clearance for Pinnacle by citing a previous metal-on-metal hip implant as a predicate.
There are 1000s of pending lawsuits that allege that cobalt and chromium ions accumulate in patients can lead to metallosis, pseudotumors and other serious conditions.