Poison alert over metal hip replacements
ALMOST 50,000 patients with ‘metal on metal’ hip replacements face increased checks amid fears they may cause serious health problems. The UK’S safety watchdog has increased vigilance on implants suspected of causing serious damage to muscle and bone from metal debris.
Friction between two metal plates in the body produces chemical fragments called ions that leak into the blood, triggering inflammation and two to three times the predicted failure rate.
The Medicines and Healthcare Products Regulatory Agency (MHRA) yesterday issued a new alert to the NHS on a wide range of implants, saying there was a ‘small risk’ they could cause complications in patients.
Hip replacements involve a ball, socket and stem. The new alert relates to those whose replacements have a ball with a diameter of 36mm or more.
Around 65,000 people in the UK have received metal on metal hip implants since 2003, of whom 49,000 are affected by yesterday’s guidance because they have these ‘large-head’ implants.
They have been told they should have annual tests on blood ion levels while those with symptoms will also need annual MRI scans.
Guidance published in 2010 said patients with large-head metal on metal implants should have annual checks for the first five years, but these have now been extended to the lifetime of the implant.
Doctors will be told to consider removing and replacing the implant if the MRI scans come back abnormal or they are concerned about rising ion levels in the blood. Among those needing greater supervision are 10,000 people with Depuy ASR implants or resurfacing devices, which were recalled in 2010.
Some of those affected will need second hip replacements but excessive wear on the hip joint can make such surgery more difficult.
The MHRA has received 370 ‘adverse incident’ reports involving metal on metal implants, including soft tissue damage, of
‘Patients put needlessly at risk’
which 242 relate to large-head implants. According to the MHRA, metal on metal implants are made by the following manufacturers: Biomet, Smith & Nephew, Finsbury, Stryker, Zimmer, Depuy, Corin, Joint Replacement Instrumentation Ltd, Implacast Gmbh and Wright Medical UK Ltd.
Solicitors are coordinating a group claim for ‘crippling pain’ and serious damage against Depuy Orthopaedics. They claimed last night that the MHRA action was ‘too late’ after figures showed metal on metal implants fail sooner than other devices such as those made of ceramic – with one in eight needing to be refitted within seven years and women being particularly badly affected.
Peter Walsh, chief executive of the charity Action against Medical Accidents, said it was ‘scandalous that patients have been put needlessly at risk by the failure by manufacturers and regulators to act quickly’.
Dr Susanne Ludgate, the MHRA’S clinical director of devices, said problems surfaced in 2008 after reports from some surgeons that patients were suffering swelling around their hip.
She said the two-year delay before advice was issued on Depuy implants was because of ‘very varied reports from surgeons’ but they had performed worse than others.
Dr Ludgate said there was a ‘small risk’ of complications from metal on metal hip implants, but in most cases they had ‘ completely transformed the lives’ of patients suffering severe pain and progressive lack of mobility.