As bad news about the safety of metal-on-metal hip implants continues to mount, it appears that more and more health care providers are deciding not to use the controversial devices. According to a report from the Minneapolis Star-Tribune, Minnesota’s renowned Mayo Clinic, for one, has dramatically curtailed its use of metal-on-metal hip implants.
Dr. David Lewallen, a Mayo orthopedic surgeon, told the Star-Tribune that more data on metal-on-metal hips needs to be gathered, though he asserted the devices still might be suitable in some instances.
“That continues to be a mystery, what is going on in these patients,” he said. “And that continues to be the ongoing mystery and the focus of investigation and work now.”
Dr. Alan Knopf, an orthopedic surgeon who teaches at UCLA and USC, was more unequivocal. “This metal-on-metal concept … has lost enthusiasm in the medical community,” he told the Star-Tribune.
Hip implant devices are made from a variety of materials including a ceramic-coated ball in a ceramic cup, a metal ball in a metal cup, and a metal ball fit into a polyethylene cup. When they were first introduced, it was thought that metal-on-metal hip implants would last longer than other varieties. But concerns about all-metal hip implants started to mount in 2010, when DePuy Orthopaedics issued a recall of its ASR hip devices, after it was found that they were failing in about 12 percent of patients within five years. Realistically, a hip implant should last around 10-15 years. The recall has sparked thousands of lawsuits.
Last May, the U.S. Food & Drug Administration (FDA) directed 21 companies that market all-metal hip replacement devices to conduct post-market studies of their products to determine if they were shedding dangerous amounts of metallic debris in patients. The shedding of metal debris may cause tissue damage, the development of cysts and pseudotumors, premature device failure, the need for revision surgery, and other long-term health problems, according to the agency.
In just the past few weeks, an astounding amount of evidence has accumulated against the use of metal-on-metal hip implants. Earlier this week, The Lancet published a study conducted by University of Bristol researchers who found that people with metal-on-metal hip implants were twice as likely to experience early failure of their device compared to those fitted with other types of implants. The authors of the study asserted the devices should no longer be used. Late last month, the British Medical Journal revealed that metal-on-metal hip implant manufacturers were aware of mounting evidence linking metal-on-metal hip replacement devices to serious, long-term health consequences, but for years failed to warn the public about these dangers.
In the U.K., the Medicines and Healthcare Products Regulatory Agency (MHRA) announced that blood tests should be conducted yearly to check cobalt and chromium blood levels in some all-metal hip implant recipients, those with bearings of 36 mm or above, as well as MRIs for any patient who does exhibit high metal ion levels. Only last week, the British Hip Society advised that larger metal hip implants be used in total hip replacement surgery.
The controversy is scaring doctors away from metal-on-metal hips. Dr. Joshua Jacobs, a professor and chairman of Orthopaedic Surgery at Rush University Medical Center in Chicago, told the Star-Tribune that the devices were once used in about one-third of all total hip procedures, he said. Now, they make up less than 5 percent.