Metal-on-metal hips cancer fears allayed
There is no evidence that metal-on-metal hip replacements increase the risk of cancer, a study suggests.
The new analysis of nearly 41,000 patients found no link in the seven years following surgery, the British Medical Journal website reported.
But the researchers - from the universities of Bristol and Exeter - said longer-term follow-up was needed.
Cancer risk was just one of the fears linked to the implants.
Regulators have already called for them to be monitored closely following reports of high failure rates.
Tiny metal ions made up of cobalt and chromium are thought to break off from the implants and leak into the blood, with fears that this leads to muscle and bone damage, and neurological issues.
The data for this study, based on the National Joint Registry of England and Wales, covered 40,576 patients with metal-on-metal hip implants and 248,995 who had other types.
The study found no evidence of an increased risk of any type of cancer in the patients.
However, researchers said "as some cancers have a long latency period it is important that we study the longer-term outcomes and continue to investigate the effects of exposure to orthopaedic metals".
Last month, experts writing in The Lancet called for all metal-on-metal implants to be banned because of evidence of high failure rates.
In February, the Medicines and Healthcare Products Regulatory Agency (MHRA) issued guidance on all metal-on-metal implants, saying 49,000 patients in the UK would need annual blood or MRI checks.
But it insisted there was a "small risk" that the implants could cause complications in patients.
The MHRA has said the clinical evidence is mixed and does not support their removal from the market.