New research indicates that 5-year-revision rates associated with metal-on-metal hip replacements began to increase significantly in 2007, reflecting changes in the way such patients were managed.
The study, which was published this month in the Bone and Joint Journal, involved 24,583 metal-on-metal hip patients who had undergone their initial hip replacement between 2003 and 2012.
An analysis indicated that patients who underwent a primary metal-on-metal hip replacement from 2007 onward had significantly higher rates of revision at 5-years post-op compared to those who received an all-metal hip prior to 2007.
“The increased number of metal-on-metal hip implant patients undergoing further surgery in recent years is likely explained by changes made in how this group of patients are managed. Our study findings are most likely attributable to the increase in regular patient follow-up combined with many surgeons now acting earlier to perform revision surgery,” one of the study authors commented in article published on the website for the U.K.’s National Joint Registry.
Metal-on-metal hip implants were brought to market in the 1990s and touted as a more durable option than devices constructed of other materials. However, a growing body of research suggests that these devices can shed dangerous amounts of toxic metal ions into the tissue around the joint and even the blood stream, resulting in adverse local tissue reactions, pseudotumors, premature device failure and other complications that will require revision to remove and replace the implant.
In a January 2013 Safety Communication, the U.S. Food & Drug Administration urged metal-on metal hip implant patients to seek medical attention if they experienced any issues with their devices. Doctors in the U.S. were advised to consider metal ion blood testing and imaging for symptomatic patients.
In 2012, the U.K.’s Medicines and Healthcare Products Regulatory Agency (MHRA) agency recommended screening for metal-on-metal hip patients considered high risk. The agency updated that advice last year, recommending annual testing for all patients with a metal-on-metal hip, “as soft tissue necrosis may occur in both asymptomatic and symptomatic patients.”
Tens of thousands of hip replacement lawsuits have been filed in U.S. courts on behalf of metal-on-metal hip recipients who suffered debilitating complications due to allegedly defective implants. In November 2013, DePuy Orthopaedics agreed to pay $2.5 billion to resolve lawsuits involving its ASR line of all-metal hips, which were recalled in August 2010 due to a high failure rate.
DePuy is also named a defendant in thousands of additional hip replacement lawsuits involving an all-metal version of the Pinnacle hip system. Four federal Pinnacle hip lawsuits have gone to trial since October 2014, three of which concluded with multi-million-dollar verdicts for plaintiffs.
In February 2014, Biomet Inc. agreed to a $56 million settlement that resolved many of the hip replacement lawsuits involving its M2a line of metal-on-metal hips. And last November, Wright Medical agreed to pay $240 million to settle nearly 1,300 cases involving its all-metal Conserve, Dynasty and Lineage hip replacements.