Tens of thousands of people with all-metal hip replacements to be called in for annual blood checks
Metal scare over hip replacement joints
Some types of metal-on-metal hip replacements do not appear to cause problems, the MHRA said. Photograph: Alamy
Nearly 50,000 people with all-metal hip replacements are to be called in for annual blood checks because of fears that metal particles shearing off the joint could cause them harm.
The Medicines and Healthcare Regulatory Authority (MHRA) issued new guidance hours before the British Medical Journal (BMJ) was due to publish an investigation into the implants, linked to a Newsnight programme in the evening.
The BMJ and Newsnight allege that hundreds of thousands of people around the world have been exposed to dangerously high levels of toxic metals in their bodies as a result of the introduction of metal-on-metal implants. One type, the DePuy ASR, was banned by the MHRA after it became clear that it caused problems and needed replacing much sooner than others.
But critics argue that the regulators have been slow to act against other metal-on-metal implants which shed metal particles into surrounding tissue. There have been a small number of cases where, it is claimed, toxic chromium and cobalt ions have leaked into the lymph nodes, liver and kidneys before leaving the body as urine.
Concerns about some of the metal-on-metal hip implants were first voiced in 2008 by surgeons who saw patients with swellings in the hip area, said the MHRA. From 2010 it advised that all patients with metal-on-metal implants should have annual tests to establish the level of metal ions in their blood.
On Tuesday the MHRA said that some types of metal-on-metal hip replacements – those with a metal ball and socket under 36mm diameter – did not appear to cause problems. Patients with those implants, about a third of the 65,000 total since 2003, did not need blood checks unless they had symptoms.
However those with implants with larger metal balls – over 36mm diameter – should have blood tests every year for the life of the implant, not just every five years as previously recommended, and an MRI scan if their ion levels are seen to be rising, which could indicate a need to replace the joint.
Patients who did not know whether they had a metal-on-metal joint should see their GP, said the MHRA.