Engineering news
A leading engineer and expert in biomedical tribology has called on surgeons to stop performing hip replacements using large head metal-on-metal total hip replacements as fears were once again raised about their safety.
Thomas Joyce, reader in biotribology at Newcastle University and a fellow of the IMechE, told PE he was frustrated about the slow pace of action over such hip replacements. One manufacturer, De Puy, was forced to recall a design in 2010.
Joyce said there was growing evidence that all large head metal-on-metal total hip replacements with diameters of 36mm or more could cause severe health problems for patients. His comments came as the MHRA, the government agency responsible for ensuring that medical devices work, announced it was changing the clinical advice on metal-on-metal hip replacements to make sure they were monitored once a year for the life of the device, instead of for just five years after the operation.
Joyce said the MHRA was acting too slowly and further measures were needed. “Why can't we just recognise there's a problem and stop for now? We need a better understanding of this problem and it is better to stop the implants.”
Problems experienced by patients due to wear of the implant and the release of metal into the body included severe pain, muscle and tissue damage, and attacks on bone, Joyce said. In some cases, the hips had dislocated leaving the patient in agony. Surgery to repair the damage was difficult and could leave patients with long-term problems while relatively young, as the large head metal-on-metal total hip replacements were originally aimed at patients in their 40s and 50s.
Joyce said: “We feel we haven't been listened to enough and I speak to a lot of patients who feel their pain and problems have been ignored.” The problems had the potential to affect between 500,000 and a million people. “I don't think we've heard the end of this,” Joyce said.
Dr Susanne Ludgate, clinical director of the MHRA, said: “Clinical evidence shows that patients have a small risk of suffering complications from having metal-on-metal hip implants. These implants have in most cases completely transformed the lives of patients who in the past were subject to increasingly severe pain and progressive lack of mobility.
“As a precautionary measure, we have issued updated patient management and monitoring advice to surgeons and doctors.”