Amid fears toxic metal-on-metal hip implants could be endangering the health of tens of thousands of people, British health regulators said yesterday that certain patients should undergo annual blood checks for as long as they have their all-metal devices to ensure that they aren’t shedding dangerous amounts of metal debris into their blood streams. According to a report from The Guardian, as many as 50,000 people in the U.K. will be advised to undergo the annual checks. Those who do test positive for high levels of metal ions will be told to undergo an MRI to check the condition of their metal-on-metal hip implants.
Metal-on-metal hip implants include DePuy Orthopaedics’ ASR Hip Resurfacing System and the DePuy ASR Acetabular System, which were recalled in 2010 because of an unusually high premature failure rate. DePuy, a division of Johnson & Johnson, currently faces more than 3,500 U.S. lawsuits over its defective ASR hip implants. Another 900 lawsuits are pending in the U.S. over an all-metal version of its Pinnacle hip replacement device, with plaintiffs claiming it is similar in design to the ASR implants and should have been recalled as well.
Since the DePuy ASR hip implant recall, concerns about all makes of metal-on-metal hip implants of grown. 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. Most recently, preliminary findings from a study conducted by researchers at the University of Bristol in the U.K. indicated that patients fitted with all-metal hip implants may be at risk of experiencing genetic changes to the cells of the bladder, a possible precursor to cancer, and possibly bladder cancer itself.
Yesterday, the U.K.’s Medicines and Healthcare Regulatory Authority (MHRA) advised that patients with metal-on-metal hip implants that have larger metal balls – over 36mm diameter – should have blood tests every year for the lifetime of their implant, according to The Guardian. Those with smaller versions do not need the checks unless they have symptoms of a failing implant, the agency said. This is a change from guidance the MHRA issued in 2010, which stated patients only needed to be monitored for five years after their operation.
According to a report from Reuters, the new MHRA guidance does not affect all-metal hip resurfacing systems that do not have a stem sticking into the bone. Other companies that make metal-on-metal hip implants subject to the new guidance include Zimmer, Stryker, Corin, Biomet, Implacast, Wright Medical, Joint Replacement Instrumentation and Finsbury/MatOrtho, the agency said.
