More than 30,000 British patients have received "metal on metal" hip replacements that could be causing "systemic toxicity" in the body, an investigation has found.
A report in today's Sunday Telegraph says there are concerns that friction between the metal ball and cup may cause minute metal filings to break off, which seep into the blood and cause inflammation, destroying muscle and bone.
30,000 Britons have received "metal on metal" (MoM) versions of the device.
The Telegraph notes that a report by the British Hip Society suggests that the failure rate for certain hip replacements, which were withdrawn from the UK market in 2010, could be as high as 50 per cent within six years of surgery.
In April 2010 the MHRA issued an alert to healthcare professionals over the safety of metal implants after some hip replacement patients began suffering soft tissue reactions.
The agency recommended that people fitted with the devices should undergo annual check-ups for five years following surgery.
It has prompted the Medicines and Healthcare products Regulatory Agency (MHRA), which is responsible for ensuring that medicines and medical devices work and are acceptably safe, to launch an investigation into the safety of metal hip replacements.
The MHRA says it has taken "prompt action" over the safety concerns, adding that the majority of people with metal hip replacements are at "low risk of developing any serious problems".
An MHRA spokesperson said: "On the evidence currently available, the majority of patients implanted with metal on metal hip replacements are at low risk of developing any serious problems.
"We are continuing to closely monitor all evidence. This needs more analysis before any conclusions can be drawn and further advice given."