A new study has found that newer artificial hips, including metal-on-metal varieties, offer patients few advantages over traditional metal-on-polyethylene or ceramic-on-polyethylene versions. The study, published in the British Medical Journal, also found that people who received all-metal hip implants were more likely to require repeat surgery than those who received traditional implants.
The hip implant study, which was commissioned by the U.S. Food and Drug Administration (FDA), compared newer metal-on-metal or ceramic-on-ceramic hip implants with traditional metal-on-polyethylene or ceramic-on-polyethylene ones, according to a report from WebMD.com. A team of researchers led by Professor Art Sedrakyan of Weill Cornell Medical College looked at 18 studies including more than 3,000 patients as well as outcomes from 830,000 hip replacement surgeries reported to various national registries.
According to WebMD, data from the three largest registries – from Australia, New Zealand, and England and Wales – revealed evidence of higher rates of early implant failure associated with metal-on-metal devices, compared to metal-on-polyethylene implants. One study showed fewer repeat surgeries for device failure for ceramic-on-ceramic implants, but the registry data did not support this conclusion. The research team was unable to find any evidence that newer hip implant types improved functioning and quality of life or reduced the need for revisions.
“A large and high-quality randomized controlled trial of bearing surfaces in total hip replacement needs to be conducted before any claims of benefit are made,” the journal article stated.
Sedrakyan told Reuters that the findings indicated that people with all-metal hip implants are doubly at risk of requiring a repeat procedure.
“There’s more work needs to be done before drawing more definitive, worldwide conclusions, but it is probably not likely to change the signal that these metal-on-metal implants are failing at a greater rate,” Sedrakyan said.
He advised patients who are about to receive a metal-on-metal hip implant to ask their doctor why they thought this type of hip implant was warranted.
As we’ve reported previously, it is believed that metal-on-metal hip implants can shed dangerous amounts of cobalt and chromium through wear, leading to tissue damage, premature device failure, the need for revision surgery, and even long-term health problems. In May, the FDA directed 21 makers of all-metal hip implants, including DePuy, Zimmer, Stryker, Biomet and Wright Medical, to conduct post-market studies of their devices to determine if they were shedding dangerous amounts of metallic debris in patients.
Metal-on-metal hip implants include DePuy Orthopaedic’s ASR hip implant, which was recalled in August 2010 because of a higher-than-expected early failure rate. Other all-metal hip replacements that have been the subject of complaints include the all-metal version of DePuy’s Pinnacle hip implant system.