Gene test to tell you if your hip surgery will fail

A SALIVA swab before your hip replacement could predict if the procedure will work.

British researchers have found that DNA signals lurking in saliva and blood samples are linked to an adverse reaction to materials in most joint implants.

About 15 per cent of Britons have these genetic characteristics, which make the immune system attack tissue around the material, causing pain and swelling.

Studies have long identified that roughly a fifth of people react badly to an artificial joint made from cobalt chrome. But until now experts didn’t know why, which meant doctors had no way of telling if a patient would react badly to their new joint or not.

Alongside discovering the genetic culprit, the research team from Newcastle University have designed a testing system that can screen patients for the gene with about 90 per cent accuracy.

In a trial, more than 600 patients who underwent joint-replacement surgery in the past ten years were tested using saliva swabs and blood tests.

A computer analysed the data and revealed those patients who suffered complications carried specific genes. The team believe they can use this testing system to spot who might be at risk.

About ten per cent of Britons will have joint-replacement surgery in their lifetime. The procedure is commonly used to fix damage related to arthritis or age-related wear and tear.

If joint replacements are successful, they last between 15 and 25 years.

Patients with a genetic sensitivity to cobalt chrome usually have a second procedure within months of the first, using alternative materials.

Dr David Langton, director of ExplantLab, a Newcastle-based organisation that investigates the links between genetics and the performance of medical devices which took part in the study, said: ‘There has been little research into why joint replacements don’t work for some patients. If a joint fails, it needs to be replaced, and this carries a much greater risk of blood loss, infection and even death.

‘Our findings are a big step towards offering patients more choice about what type of joint implant they decide on, and helping them to make informed decisions about the risks involved.’