Agency tells surgeons not to use a type of hip implant cup liner because of high revision rates

Surgeons should stop using a particular type of cup liner that is used in some metal-on-metal hip operations because the revision rate is higher than it should be, the Medicines and Healthcare Products Regulatory Agency (MHRA) has said.

The R3 metal cup liner—part of the implant that fits into the cup—is used with the R3 Acetabular System total hip replacement prostheses made by UK company Smith and Nephew.

“Post-market surveillance data has shown a high revision rate of 6.3% at four years for patients implanted with the R3 metal liner. This high revision rate is not in line with the 4% guidance figure at four years from the National Institute for Health and Clinical Excellence (NICE) and therefore the MHRA has told surgeons to stop using the metal cup liner,” the MHRA said.

Surgeons have been told to monitor annually the 281 patients who have been fitted with these cup liners so that any complications such as pain or swelling are picked up and treated early.

The statement by the MHRA comes two days before the Food and Drug Administration is due to meet to discuss the safety and effectiveness of metal-on-metal hip arthroplasty. The MHRA is keen to stress its proactive approach saying it was the “first regulatory agency in the world to issue advice to clinicians about metal-on-metal hip implants in April 2010.”

The MHRA statement follows a company initiated voluntary worldwide recall of the product, which it made after it reviewed data from both the UK and Australia. In England and Wales, companies have access to data on their own devices from the National Joint Registry (NJR), and in Australia, they can obtain data from the Australian Orthopaedic Association’s National Joint Replacement Registry.

According to Professor Stephen Graves, director of the Australian registry, the revision rate in Australia is higher than in the UK, reaching almost 5% at two years, and Smith and Nephew confirmed these figures.

The MHRA has also told surgeons to monitor annually patients who were experiencing pain or swelling from their metal-on-metal hip resurfacing implants or metal-on-metal hip replacements that had a head diameter below 36 mm.1 The new advice of annual monitoring replaces previous patient monitoring advice for this size of implants that patients should be followed up for a minimum of five years.