Boneshaker shows loose hip joint

A quarter of the people who have new hip joints will suffer pain because the fixing cement is failing. University of Bath engineers placed a device on the knee, then used an ultrasound receiver to measure the different sound waves produced.

An orthopaedic surgeon said it might help spot those needing new operations. The key to the technique is a tiny gap between the replacement hip joint and the bone which is caused when the metal joint becomes loose. When the leg bone is vibrated, a secure connection will lead to a marked difference in the sound compared with sound waves from a loose joint.

Dr James Cunningham, who led the project, said that his method was far more sensitive than the traditional X-rays used by surgeons trying to work out why hip patients were in pain.

He said it might help prevent the need for unnecessary surgery.