The United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA) has issued a safety warning for MITCH TRH acetabular cups and MITCH TRH modular heads – a metal-on-metal hip implant system manufactured by U.K.-based Finsbury Orthopaedics, a division of DePuy Orthopaedics. Both companies are owned by healthcare giant Johnson & Johnson.
The MITCH TRH System is a metal-on-metal hip replacement system consisting of components that can be used in different combinations to carry out either hip resurfacing arthroplasty or total hip replacement. In the new Medical Device Alert, MHRA regulators warn that a higher-than-expected number of DePUY MITCH hip devices require revision surgery within four years if they are implanted in combination with uncemented Accolade femoral stems made by Stryker Orthopaedics.
According to the MHRA, analysis of data from the England and Wales National Joint Registry (NJR) up until March 10, 2012 has shown that the cumulative revision rate for DePuy’s MITCH TRH System to be 10.7 percent just four years after implementation. Additionally, NJR data showed that 8.8 percent of MITCH TRH hip resurfacing systems resulted in revision surgery in four years – a level considered unacceptably high by the country’s National Institute for Health and Clinical Excellence (NICE).
The agency also reiterated its recommendations for patients implanted with all types of meal-on-hip devices to be checked annually throughout the life of the implant for signs of poisoning stemming from elevated metal levels in the blood – a condition that can be caused when friction between the all-metal hip device components releases particles of chromium and cobalt into the body. The MHRA also recommended MRI scans for all patients whose blood test display irregularities involving metal ions.