More warnings on metal-on-metal hip implants in U.K, New Zealand

Regulators in the U.K. and New Zealand are warning again about higher-than-expected revision rates for certain metal-on-metal total hip replacement systems that use a combination of components made by Johnson & Johnson‘s (NYSE:JNJ) DePuy Orthopedics division and Stryker (NYSE:SYK).

The Medicines & Healthcare products Regulatory Agency, an executive agency of the U.K. Dept. of Health, issued a warning yesterday about elevated revision rates for Mitch TRH acetabular cups and Mitch TRH modular heads manufactured by DePuy’s Finsbury Orthopaedics unit when used in combination with uncemented Accolade femoral stems manufactured by Stryker Orthopedics.

The revision rate for a less-invasive procedure using the Mitch TRH device, called hip resurfacing arthroplasty, fall in line with guidance, according to the regulators.

"But that the cumulative revision rate for Mitch TRH System total hip replacements (revision rate of 8.8% at 4 years based on 445 patients recorded by the NJR) is higher than indicated as acceptable by the National Institute for Health and Clinical Excellence," according to the agency.

A further analysis of the data by DePuy found that revision rates varied considerably depending on the type of femoral system being used, according to the report, and that the Mitch TRH with un-cemented Accolade had a revision rate of 10.7% after 4 years.

Regulators are warning surgeons not to implant the devices in combination with each other and encouraging them to conduct annual follow-ups with all patients who received the implants for the life of the implant, to test for rising metal ion levels in their blood.

In New Zealand, Stryker is asking surgeons to contact 41 patients there who received the implant, according to a report in the Australian News.

In August 2010, DePuy recalled both the ASR resurfacing implant and its related ASR cup due to a high rate of revision surgeries required to correct or remove the defective implants. The pair of implants were used on about 93,000 patients worldwide.

Warsaw, Ind.-based DePuy Ortho snapped up Finsbury in 2009 for $95 million. Stryker Orthopedics distributed the systems in the U.K from 2006-2011.