Joint detector

A more efficient way of detecting loosened artificial hip implants, which affect thousands of people every year, has been developed at a UK university.

Engineers at the University of Bath have developed a diagnostic test which measures the frequency of sound produced when the femur bone in the leg is vibrated.

The new method is much more sensitive than the traditional method of using x-rays to detect the loosening of implants, and so can diagnose much smaller gaps around the implanted joint.

Around 50,000 people receive total hip replacements in the UK each year, and many will go on to develop pain from them. It is estimated that within 10 years of having an implant, about a quarter of patients will suffer pain from a loosening of the joint, which are joined to their leg bone by a special cement.

Surgeons find it difficult to know whether this from an infection, which can be cured by antibiotics, or because the joint has loosened, which means surgery is needed. A reliable diagnostic test is vital to save patients undergoing unnecessary surgery.