Study: Metal-on-Metal Hip Implants Associated with Increased MortalityJun 29, 2016
A study published in PLOS One found that at ten year follow up or longer, use of metal-on-metal implants for total hip arthroplasty was associated with increased mortality. Metal-on-metal hip replacements have been under scrutiny after being subject to high profile recalls, which were issued due to higher-than-expected failure rates. The all-metal devices can release metal particles when the surfaces rub together, causing various health problems.
The authors conducted the meta-analysis because "There are concerns about increased mortality in patients with metal-on-metal bearings in total hip arthroplasty (THA)." The analysis included data from 47 studies, with 4,000 THA in randomized trials and over 500,000 THA in observational studies. Overall, increased mortality was associated with metal-on-metal bearings for THA at 10-year follow-up or longer. "Meta-analysis suggests there may be an increased long-term risk of mortality and revision surgery for patients with MOM THA compared to patients with non-MOM THA." the authors concluded.
In their discussion, the researchers state that the increased risk of mortality may reflect a dose-response association as it was only identified in long-term follow-up. They hypothesize that patients may be subject to greater risks the longer they are exposed to metal-on-metal THA. The authors also noted that metal-on-metal implants were associated with more revisions compared to non-metal-on-metal. In their conclusion, the authors state that there is no current reason to use metal-on-metal bearings for THA, stating "There is currently no case for the use of MOM THA giving the increased risk of long-term mortality and revision without any proven major advantage. Considering the results discussed above, it is prudent to closely follow the patients that have already received a MOM THA, especially in the long-term."
Metal-on-metal hip implants have been the subject of thousands of lawsuits, some of which has gone to trial. A number of lawsuits were filed against J&J, who recalled its DePuy ASR hip implant in 2010 due to a high failure rate. In March, a Dallas jury issued a verdict in favor of five plaintiffs, awarding $360 in punitive damages. The jurors found J&J and DePuy liable for failure-to-warn and design defect claims. J&J was ordered to pay $240 million and DePuy to pay $120 million. Additionally, $140 million was awarded in compensatory damages; this is to be divided among the five plaintiffs.