Researchers indicate that women may be almost 30% more likely than men to have a total hip replacement fail, leading to the recommendation that gender be considered an important factor in patient management and device innovation.
In a study published by the medical journal JAMA Internal Medicine on February 18, which was funded by the FDA, researchers found that woman face a greater risk of implant failure following total hip arthroplasty, also known as hip replacement.
Researchers conducted a prospective cohort study of more than 35,000 patients who underwent hip replacement surgery at 46 hospitals in the Kaiser Permanente health system. They found that, overall, women were 29% more likely to suffer a total hip arthroplasty implant failure than men.
Women were also found to use smaller femoral heads and were more likely to use metal on polyethylene hip implants, as opposed to metal-on-metal ones. More than a quarter of women who received hip implants received a 28-mm femoral head, compared to only 13.1% of men, and slightly more than 60% had a hip replacement system made of metal on highly cross-linked polyethylene bearing surfaces, compared to a little more than 53% of men.
Men were more likely (554.% to 32.8%) to have a 36-mm or larger femoral head and just under 20% of men received a metal-on-metal hip replacement system, compared to just under 10% of women.
The study did not reveal why the failure rates were higher among women, who receive the majority of artificial hip implants in the U.S. Researchers determined that gender was an important factor in total hip arthroplasty patient management and device innovation.
High Failure Rates Lead to Safety Concers Over Metal-on-Metal Hips
The study comes at a time when metal-on-metal hips are under particularly close scrutiny.
In January, the FDA released new guidance for metal-on-metal hip replacements. The agency told doctors that metal-on-metal hip replacement systems should only be used if other artificial hip implants were not appropriate, and called on manufacturers to prove that their implants were safe enough to stay on the market. Future metal-on-metal hip designs will have to undergo extensive human clinical trials before being made available for sale, the FDA decreed.
Currently, the first trial of thousands of lawsuits against DePuy Orthopaedics over its recalled ASR metal-on-metal hips is underway in California, with a number of former Johnson & Johnson employees and other witnesses providing testimony that suggests the manufacturer knew about the risk of problems with metal-on-metal hips long before they issued the ASR recall. Some internal documents offered during the trial have suggested that the company’s own predictions estimated a failure rate may reach as high as 37%.
In addition to lawsuits over the DePuy ASR, other metal-on-metal hip designs have been the focus on large numbers of complaints, including the DePuy Pinnacle hip, Biomet M2A Magnum hip and Wright Medical Conserve Cup.