Metal-on-Metal Devices Such as DePuy Pinnacle Failing at Alarming Rate

Baton Rouge, LAA recently released report from Europe warns that metal-on-metal hip implants, a class of hip implant that includes a product in the DePuy Pinnacle line, are failing at an alarming rate. The DePuy Pinnacle hip replacement in question, called the Ultamet, is one of a number of metal-on-metal hip replacement devices available for patients. Unlike the DePuy ASR, also made by DePuy Orthopaedics, the DePuy Pinnacle Ultamet has not been recalled. If the new report is any indication, however, the Ultamet could one day face a similar fate as the ASR.

The report was released by the National Joint Registry for England and Wales (found online at njrcentre.org.uk), and reported by The New York Times (09/15/11). According to the report, the DePuy ASR, an all-metal hip, failed in approximately one-third of the patients who had been followed for the longest period. Meanwhile, the same report indicated that other metal-on-metal hip replacement devices had a significantly higher early failure rate than hip replacement devices made from other materials.

Metal-on-metal hip replacement devices use both a ball and socket that are made of metal. They were designed to be more durable than traditional hip replacement devices that often included a ceramic or plastic component. Concerns about the all-metal devices, however, are that metal debris can come loose from the joint and be absorbed by the patient's tissue, causing a condition known as metallosis.

Typically, artificial hips are expected to last around 15 years before replacement. Some reports indicate that the all-metal hips are failing with alarming frequency after five or six years. Failure of a hip implant device often causes extreme pain and mobility issues, and may require the patient to undergo revision surgery, which comes with added risk of complications.

According to The New York Times (08/22/11), which analyzed data from the US Food and Drug Administration (FDA) reporting system, the FDA received more complaints about all-metal hips between January and June 2011 than it had in the previous four years combined. The agency reportedly received more than 5,000 reports of problems with the all-metal hips since the beginning of 2011. The increase in complaints resulted in the FDA requiring makers of the all-metal devices to study the frequency with which they were failing and what implications that would have for patients.

Meanwhile, the report from the Joint Registry noted that of patients who received the ASR (Articular Surface Replacement) six years ago, approximately 30 percent have already undergone revision surgery. In patients who received the same device five years ago, around 17 percent have had it replaced. The ASR was recalled in 2010 because of concerns about the high failure rate. Furthermore, the failure rate for all-metal devices as a whole is reportedly increasing more quickly than the failure rate for other hip replacement devices. According to the Joint Registry, when considering all metal-on-metal devices, after five years, approximately seven percent of patients required revision surgery while that number jumped to approximately 10 percent after six years.

In its report, the Joint Registry noted, "Some studies have raised concerns about metal-on-metal implants in terms of higher revision rates and poorer patient outcomes (related to pain and function) compared with other bearing surfaces. In particular, there are concerns about the possibility of metal debris damage to soft tissue surrounding the joint (metallosis) and the uncertain effects of any release of cobalt and chromium ions into the patient's blood." The Joint Registry goes on to note that while the results for the ASR are worse than for the all-metal group as a whole, even when the ASR results are excluded, the all-metal group still has a high revision rate.