Fresh fears have been raised over the safety of hip replacements received by tens of thousands of British people.
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9:00PM GMT 04 Feb 2012
Comment
Early findings from a study on the effects of "metal-on-metal" devices suggest the implants could increase the risk of cancer and genetic damage.
One patient who took part in the research, and was found to have abnormal cell changes to the bladder, said he was now desperate to have his implant removed because he feared for his long-term health.
The British study is understood to have detected changes to cells in the bladders of more than one in five patients who were monitored after being given "metal-on-metal" hip replacements.
The disclosure of the study comes after last week's investigation byThe Sunday Telegraph, which revealed that regulators have such grave concerns about the safety of 30,000 of the devices that they are preparing to issue new guidance on them.
Problems occur with the implants when friction between the metal ball and cup causes minuscule metal filings to break off, which can seep into the blood and cause inflammation, destroying muscle and bone.
There are also concerns that metal traces in the blood could put major organs at risk of being slowly poisoned, and increase the chance of cancer - in particular in the kidneys and bladder.
The new in-depth research on 72 patients found genetic damage to the bladders of 17 people - including three patients who developed full-blown cancer.
The proportion of patients who had suffered DNA damage may be significant, because such changes can cause mutations which in turn lead to cancer.
Orthopaedic consultants in Bristol who undertook the study said they hope to present the results to other surgeons next month.
Their study was launched after the Medicines and Healthcare products Regulatory Agency (MHRA) warned that all 40,000 Britons with "metal-on-metal" devices should undergo annual checks, with scans and blood tests if doctors find symptoms that suggest metal leakage.
A type of device made by one company, DePuy - a subsidiary of global health giant Johnson & Johnson - which was received by almost 10,000 patients was taken off the market in 2010 because of concerns about its high failure rate.
One of the participants in the trial, David Jose, 51, from Clifton, near Bristol, had a hip "resurfacing" operation in 2007, a year before retiring as a police officer.
The father of two had been suffering hip pain from playing football and rugby.
In May last year he was told that the tests had found atypical cells which were not at this stage cancerous.
He saw Angus Maclean, an orthopaedic surgeon at Southmead Hospital involved in the study, who said that the trial had established three cases in which patients had developed bladder cancer, and 14 more including Mr Jose who had changes to their chromosomes.
The doctor told him researchers "could not believe" what had been found, describing the findings as "shocking".
He said he was expecting the research to "make front page news", when it was published in a couple of months' time. Nine months on, the findings have not been published.
Mr Jose, who now suffers from a host of unexplained health problems has now undergone further procedures which have established that so far he does not have bladder cancer.
However, he remains in fear about the consequences of the cell changes, and is desperate to have the device removed.
He said: "I do not know what this thing is doing to me; that is what is frightening, the fact that this is all unknown."
Mr Maclean said he could not talk about the study, except to say that he hoped the findings would be presented next month, at the annual British Hip Society conference.
A spokesman for the University of Bristol, which is running the study, said analysis of the results from the trial was still ongoing, and that the research would be peer reviewed and published.
The MHRA said there was no evidence of an increased incidence of cancer among people with metal-on-metal replacement hips.
A spokesman for DePuy said that since the recall decision, the company had worked to provide patients and surgeons with the information and support they needed.
Metal-on-metal implants were introduced in the UK in the 1990s when they were promoted as offering better mobility than replacements which use a metal ball and plastic socket.
They were seen as a better option for younger patients, who were likely to be more active and put more pressure on the joint.
The problems have been found to affect people of all ages but studies have found young and petite women are particularly at risk.
