Metal-on-metal hip replacements have been used for a number of years to give people who struggle to get around the opportunity to walk without pain, but research has revealed that the implants can cause serious side effects as they wear.
The dangers were so much so, that expert surgeons in the UK have said patients should no longer be given metal hip joints.
The advice comes after the British Medical Journal discovered that the problems with the implants have been known about for decades.
According to the Medicines and Healthcare products Regulatory Agency (MHRA), patients who have undergone the procedure and now have a metal-on-metal hip joint should be monitored for life to ensure side effects are reduced.
As the metal joint wears down, debris can break away, having a major impact on the comfort and health of the patients who have the replacement. The pieces of chromium and cobalt metal can leak into the blood and cause muscle and bone damage as well as neurological issues. It said 49,000 patients with large-head hip implants have been affected.
As well as the medical issues caused by wear and tear of the joint, researchers believe that metal-on-metal has a high failure rate. In a number of cases in the UK alone, joints have come loose over time through dislocation or general wear and tear.
Researchers at the University of Bristol analysed information from 402,051 hip replacements recorded in the National Joint Registry of England and Wales, and showed that, overall, 6.2 per cent of metal-on-metal hips had failed within five years, much higher that metal-on-plastic and ceramic-on-ceramic replacement.
After the latest data, the clinical director of the MHRA, Dr Susanne Ludgate, said: “We recognise that there is emerging evidence of increased revision rates associated with large head metal on metal hip replacements. But the clinical evidence is mixed and this does not support their removal from the market.
“We will take quick action if we need to and, if patients have any questions, they should speak to their orthopaedic surgeon or doctor.”
In recent years, the number of metal-on-metal implants being fitted has dropped significantly, from 8,072 in 2008 to just 673 in 2011, and surgeons have now been urged not to use metal implants due to the “unacceptably” high failure rate.
One man in Northern Ireland is seeking compensation after he had to undergo a second hip replacement operation when his initial metal-on-metal implant failed. Austin Willis is among thousands of patients worldwide who believe faulty hip-repair implants have caused serious health problems.
Mr Wallis has his initial operation in 2009 and was fitted with a metal-on-metal implant, a procedure which left him in pain for four months, before an X-ray indicated he had an infection around the joint.
In February 2011 he had a second operation to replace the implant with a ceramic-on-ceramic joint and is now looking for personal injury compensation for the time he spent struggling to walk.
Susanna Derham, a 40-year-old mother from Surrey, is also taking legal action after her metal hip replacement caused her agony, wearing away after just four months of its expected 25-year lifespan.
There has also suggestions that metal-on-metal hip replacements could have further-reaching side effects, with some claiming the implants could cause cancer in those with them fitted.
However, a new study revealed by the British Medical Journal revealed that there was no evidence to suggest that those with metal-on-metal replacements had a higher risk of being diagnosed with cancer.
The analysis of 41,000 patients found no link in the seven years immediately after being fitted with the metallic device.