Thousands of patients with “metal-on-metal” hip implants will be recalled for a battery of tests, including MRI scans and blood tests, due to concerns over toxicity.

The alert, issued by the Medicines and Healthcare products Regulatory Agency (MHRA), expands the pool of patients believed to be at risk of bone or muscle damage from the devices, which have been implanted in around 56,000 patients in the UK.

A large number of these patients already attend annual checkups, due to existing concerns over the devices where they are given questionnaires, blood metal tests and scans to establish whether metal particles have sheared off the implants and been deposited in surrounding tissue. If this happens, revision surgery may be required.

Previously, patients with certain sizes of device were considered low risk, but the latest guidance suggests that all patients with “metal-on-metal” hips – including those who have had the devices for many years with no problems – should now be followed up. This will mean thousands of extra patients will need to undergo testing, although the MHRA said it does not anticipate an increase in the number of revision surgeries.

The MHRA’s clinical director of medical devices, Dr Neil McGuire, said: “We’ve now included a group of people who were at low risk, but were not at no risk. It’s more about catching people who could be developing these complications early.”

The new guidance, aimed at doctors, was issued after MHRA’s experts found that soft tissue necrosis may occur even in patients who are not suffering symptoms such as hip pain or swelling.

McGuire said: “We have updated the current advice to ensure patients with metal-on-metal hip implants continue to receive appropriate follow up to detect emerging complications should they arise.”

“Hip implants have positively transformed the lives of many patients who in the past were subject to increasingly severe pain and progressive disability. These use a variety of metal, plastic and ceramic components.”

“Although the majority of patients with these metal-on-metal devices have well-functioning hips, it is known some may develop soft tissue reactions related to their implant. The clinical advice we have received indicates patients will likely have the best outcomes if these problems are detected early, monitored and treated if necessary.”

Patients who did not know whether they had a metal-on-metal joint should speak to their GP, the MHRA advised.

