UK Identifies Higher-than-Anticipated Revision Rate for DePuy's ASR
BY LAUREN UZDIENSKI, MAY 26, 2010
Citing registry data, the UK released a medical device alert noting that DePuy's ASR acetabular cups have a higher-than-expected revision rate. While regulators anticipated a revision rate of about 3%, the actual rate has been closer to 4-5%. In addition to the registry data, two of the UK clinical sites that implant the device have echoed the higher failure rate. DePuy has been marketing the device, which is used in both resurfacing procedures and traditional hip replacements, in the UK since 2003.
The need for revision appears to be correlated with the complexity of implant placement. In the alert, the MHRA (the UK's health regulator) says that DePuy updated its instructions for use in 2008 to reflect post-market feedback, emphasizing a cup inclination angle of between 40 and 45 degrees. The company also distributed a document on proper angling of the device in 2009 as well as in a field safety notice circulated in March of this year.
Device placement is not the only safety issue to dog the ASR. The device is metal-on-metal, and this category of bearing surfaces came under scrutiny earlier this year for ion debris. Devices shedding high levels of metal ions have been associated with inflammation and early failure rates.
Though the ASR continues to attract attention, its clinical use is being phased out by DePuy, who say they plan to stop selling the device by year-end. In comments quoted by the New York Times, the company says they will no longer sell the ASR for commercial reasons ("declining sales of this particular product in its market segment"), rather than safety concerns, and are "focusing on newer technologies."
