The UK's Medicines and Healthcare products Regulatory Agency (MHRA) on Thursday issued an alert to healthcare professionals with updated recommendations for long-term follow-up for patients with metal-on-metal hip replacements.
Safety and durability concerns about metal-on-metal hip replacements, along with a scandal involving faulty breast implants, were a driving factor in the EU's decision to overhaul its medical device and in vitro diagnostics regulations.
Previously, MHRA's recommendations focused on larger metal-on-metal hip replacements (≥36mm) and certain implants made by Johnson & Johnson subsidiary DePuy Synthes, which were thought to be riskier than other types of metal-on-metal hips.
In August 2010, DePuy recalled two models of its ASR hip replacement systems, and in 2013 the UK's National Health Service (NHS) stopped performing most metal-on-metal hip replacements, citing high failure rates. However, tens of thousands of patients in the UK still have the devices implanted.
In 2012, MHRA recommended annual screening involving blood tests and imaging for all patients with metal-on-metal hip replacements that showed symptoms of tissue reaction to the implant and for all patients, regardless of symptoms, that had larger or DePuy ASR implants. For asymptomatic patients with other types of implants, MHRA said the decision on follow-up screening should be made "according to local protocols."
However, now MHRA says more patients should be screened annually, extending its recommendation to all female patients that have had hip resurfacing, male patients with a femoral head implant diameter ≤48mm and all patients with large size stemmed total hip replacement.
According to the agency, recent reports have added to the evidence that wear on these devices can cause soft tissue reaction, even in asymptomatic patients.
"MHRA's clinical orthopaedic experts have also obsesrved that soft tissue necrosis may occur in both asymptomatic and symptomatic patients, and believe that early detection of these events should give a better revision outcome should this become necessary," the agency says.
"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 indicates patients will likely have the best outcomes if these problems are detected early, monitored and treated if necessary," said Neil McGuire, MHRA's clinical director of medical devices.