A joint investigation led by the British Broadcasting Company (BBC) and the British Medical Journal (BMJ) has found that DePuy Orthopaedics and other manufacturers of all-metal hip implants may have known about the serious risks these devices have posed for years but failed to remove them from the market.
The investigative report comes as Great Britain’s Medicines and Healthcare products Regulatory Agency (MHRA) issued a new advisory to nearly 50,000 all-metal hip implant recipients in the U.K., urging them to undergo annual tests to check for possible complications arising from the risky devices. The advisory replaces a previous recommendation that patients with metal hip implants undergo such testing once every five years.
DePuy, a division of the Johnson & Johnson healthcare conglomerate, recalled its ASR XL Acetabular hip implants and ASR Hip Resurfacing System in August 2010 after clinical data showed the devices were prone to fail prematurely. Other safety risks associated with the devices include the leeching of metallic particles into the body, leading to blood poisoning, muscle and bone decay, cancer, and other serious adverse reactions.
DePuy recalled the implants after they had been implanted in 93,000 patients worldwide. In some cases, the problems have been so severe that patients have had to undergo revision surgery to have their DePuy hip implants removed and replaced with more conventional devices made of metal and plastic or ceramic parts.
According to the BBC/BMJ report, about 65,000 Britons have received all-metal hip implants. Of those, 49,000 received large-head metal hip implants and are believed to be at high risk of developing serious complications, caused when friction between the devices’ all-metal components release metal particles of cobalt and chromium into the body. One orthopedic surgeon told BBC/BMJ investigators that because of the flawed all-metal hips, his hospital is “seeing patients with 10, 20, 50 times normal levels” of these metallic particles in the blood, adding that one patient had blood metal levels 300 times higher than normal.
The BBC/BMJ investigation also found that “in a bid to prevent dislocation and increase movement DePuy, like other manufacturers, altered its design of its device, making the “head” larger and part of the “stem” shorter.
The BBC/BMJ investigators said that DePuy and other manufacturers made modifications to the design of their all-metal hip implants after they had already been approved by regulators by “making the ‘head’ larger and the ‘stem’ shorter,” and it appears those alterations are responsible for causing serious illness and injury in many patients.
The BBC/BMJ investigation “shows that in the face of mounting evidence of risk from metal-on-metal hips manufacturers remained silent and regulators failed to act.”
“This is one very large uncontrolled experiment exposing millions of patients to an unknown risk,” Michael Carome, Deputy Director of Public Citizen’s Health Research Group, told the BBC. “We will only find out about the safety of these devices after large numbers of people have already been exposed,” he added.
“This isn’t the unlucky failure to spot the misdemeanours of one rogue company or the occasional unforeseen breakdown of a small number of devices,” BMJ investigations editor Deborah Cohen said of the investigation’s findings. “It is the inability to prevent a whole class of failing hip implant from being used in hundreds of thousands of people globally.”