Fresh warning over metal-on-metal hip implant

Advice for surgeons as high revision rate reported for Smith & Nephew cup liner

A probe into the potential risks of metal-on-metal hip replacement implants has led to the publication of a Medical Device Alert advising against the use of a particular metal cup liner.

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued fresh advice to surgeons that they should stop using the R3 metal cup liners following a product recall by manufacturer, Smith & Nephew. The recall concerns the cup liner component of the R3 Acetabular System, which is used in conjunction with Smith & Nephew hip replacement femoral components.

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 rate is not in line with the 4% guidance figure at four years from the National Institute of Health and Clinical Excellence (NICE).

As a result of the findings, the MHRA has told surgeons to stop using the liner and to annually monitor the 281 patients who have been fitted with the devices so that any complications such as pain or swelling are picked up and treated early.

The regulator has also issued updated advice to surgeons about extending the period of follow-up to annual monitoring of patients if they are experiencing complications such as pain or swelling from their metal-on-metal hip resurfacing implants or metal-on-metal hip replacements that have a head diameter below 36mm. The new advice replaces previous patient monitoring advice for the specific size of implants that patients should be followed up for a minimum of five years.

The new information is viewed as a routine patient monitoring advice update by the independent expert advisory group that was set up by the MHRA to look at the management of patients with metal-on-metal hip implants following concerns over the high revision rate. The MHRA states there is no new evidence of an increased safety risk associated with metal-on-metal hip implants and people with implants who are not experiencing any problems do not need annual monitoring.

Dr Susanne Ludgate, the MHRA’s clinical director of medical devices, said: “In the UK, 281 patients have been fitted with this specific R3 metal cup liner. Evidence from post market surveillance data has shown that the revision rate for this implant is high and that is why we have taken action to advise surgeons to stop using this device and to monitor the patients implanted with this cup liner on an annual basis.

“Clinical evidence shows that patients have a small risk of suffering complications from having metal-on-metal hip implants, but we believe, after advice from our expert advisory group, that it makes sense for surgeons to annually monitor any patients who are showing any symptoms. By monitoring patients with symptoms every year, any complications will get picked up and they can be treated earlier.”

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