A doctor who supervised clinical testing for the metal-on-metal version of DePuy Orthopaedics’ Pinnacle Hip Replacement System told a U.K. court this week that those experiments were seriously flawed.
According to a report from The Telegraph, the all-metal Pinnacle Ultamet system underwent four rounds of tests at DePuy’s UK headquarters in Leeds between 2000 and 2004. Dr. Frank Chan supervised those experiments, but was not required to be present.
During testimony before the High Court of London, Dr. Chan acknowledged that low wear rates reported from trials of the Pinnacle’s 38mm cobalt chrome heads were distorted by a surface buildup of proteins that should have been removed. Failure to properly clean the components during testing could have had “important clinical ramifications” for recipients of the device.
Dr. Chan was also shown emails where he and several colleagues brainstormed solutions after three out of five cup and ball fixtures “appeared to move”. He ultimately agreed that “clearance” threshold should be increased from around 60 microns to between 80 and 100 microns.
However, the plaintiffs’ lawyer pointed out that further tests carried out in 2001, 2002 and 2003 confirmed that a protein buildup between the Pinnacle system’s head and liner caused increased friction between components.
The DePuy hip replacement lawsuit currently at trial in London was filed on behalf of more than 340 plaintiffs, all of whom allege that the Pinnacle hip/Ultamet liner configuration was wrongly marketed as having lower wear rates than competitor devices. They further assert that the hip replacement’s all-metal design caused toxic metal ions to be released into the body, resulting in premature failure of the device and a range of other health problems.
Metal-on-metal hips like the Depuy Pinnacle – Ultamet combo were marketed as a longer-lasting and more durable alternative for younger, more active patients. However, studies have shown that that metal ions released from the devices place patients at risk for adverse local tissue reactions, metallosis, pseudotumor formation, and other problems that can result in premature hip replacement failure.
Hip replacements should last around 15 years. But in January 2013, the U.S. Food & Drug Administration warned that metal-on-metal implants were more likely to fail early compared to other configurations. Patients were advised to inform their healthcare provider if they experienced any issues with their implants, while it was recommended that doctors consider metal ion blood testing and imaging for metal-on-metal hip recipients who reported problems with the implants.
DePuy Orthopaedics and its parent company, Johnson & Johnson, have been named defendants in more than 9,000 U.S. lawsuits involving the metal-on-metal Pinnacle hip, the majority of which have been consolidated in a multidistrict litigation now underway in the U.S. District Court, Northern District of Texas. The federal proceeding has already convened three Pinnacle hip trials, two of which concluded with verdicts for plaintiffs. The litigation is currently in the midst of its fourth trial.
In November 2013, DePuy Orthopaedics announced a $2.5 billion hip replacement settlement to resolve clams involving its ASR line of metal-on-metal hips
DePuy ended sales of the all-metal Pinnacle hip system that same year, ostensibly due to “low clinician use”