Replacement hips linked to dementia, heart disease

BRITAIN: Medical regulators are investigating whether thousands of people are at risk of heart problems and dementia because of toxic hip replacements.

Concern is growing over patients who have been poisoned by cobalt and chromium leaching into their blood from metal-onmetal hip implants.

Britain’s Medicines & Healthcare Products Regulatory Agency (MHRA) has set up an expert group to establish if there is a wider problem that could affect many more of the 56,000 people in the country with such hips.

It has been known for a decade that metal-on-metal hips can damage bone and surrounding tissue as they shed tiny particles into the joint and such implants are no longer used. Last week the MHRA said everyone with such hips should be checked regularly because by the time symptoms emerge it can be impossible to repair any damage.

Neil McGuire, clinical director of medical devices at the MHRA, said regulators had also been keeping a ‘‘weather eye’’ on reports of patients who had problems with their heart, cognition or memory as a result of hips shedding large amounts of metal. In some cases such symptoms disappear when the joints are replaced with plastic or ceramic alternatives.

Cobalt is poisonous in high doses and McGuire said he wanted to establish whether this could have a clinical impact and, if so, what should be done about it.

‘‘It may turn out that we’re chasing smoke, but it may not. If we do find something we’re not going to keep quiet about it.’’

It was difficult to disentangle cause and effect, McGuire said, especially because heart and brain problems tend to develop at the same age at which people typically have hip replacements.

‘‘We’re always balancing depriving people of the benefits of these devices versus protecting people from harm. We don’t want to set a lot of hares running if there’s nothing to find.

‘‘It may be at the end of it we say, ‘There’s nothing to see here folks’.’’

Last year Australian scientists studied 4000 patients and reported a higher risk of heart failure in men with one type of metal hip.

A study this year looked at 10 patients whose implants were being replaced and found that nine had depression and seven had memory and cognition problems.

Ben Green, of Chester University, who led the study, said: ‘‘This was consistently over and above the levels that you may expect to find in a comparable age groups.’’

He said he was studying if the symptoms were triggered by the implants, and urged doctors treating patients with such hips to check their mental state.

Mark Wilkinson, of Sheffield University, however, said that with only 30 confirmed cases of serious poisoning among a million worldwide with metal-on-metal hips, a big problem was unlikely.

– The Times