Tiny microphone could revolutionise osteoarthritis diagnoses

A tiny microphone usually employed by engineers to detect faults in bridges could represent a big breakthrough in healthcare. Scientists from Lancaster University have discovered that people’s joints emit a high-frequency sound that reveals whether or not they are stiff or swollen.

Totally inaudible to the human ear, these sounds can be picked up by the microphone and processed by a computer to analyse the specific wavelength to offer a diagnosis. Leader of the study, Professor John Goodacre, believes it could revolutionise the ‘crude’ way that the most common form of arthritis - osteoarthritis - is detected.

Osteoarthritis patients’ bodies do not repair the damage caused to the joints by everyday life. Ruptured cartilage means there is no protection for the joints and they become stiff and painful. It’s especially a problem in old age and can contribute to a lack of independence, as sufferers see their mobility eroded.

Professor Goodacre’s team, along with a number of NHS clinicians and scientists, strapped tiny microphones to patients’ legs to listen to their noisy knees. Some 89 participants with osteoarthritis were monitored for the study, with each one performing a standing to sitting movement with the apparatus attached.

The microphones are designed to allow structural engineers to listen for smooth surfaces when working on projects like developing bridges. Gaps in the acoustic sounds show rough surfaces, which allowed the scientists to detect osteoarthritis in the participants.

Professor Goodacre said: “This work is very exciting because it involves scientists and clinicians working together as a team to develop an entirely new approach. Potentially, this could transform ways in which knee osteoarthritis is managed. 

“It will enable better diagnosis, and will enable treatments to be tailored more precisely according to individual knee condition. It will also enable faster, bigger and better clinical trials of new treatments.”

At present, the methods used to diagnose osteoarthritis involve patients giving an account of their pain and the symptoms they’ve been experiencing. This is then investigated further with the use of an X-ray, but depends on a certain amount of interpretation from clinicians.

X-rays are often found not to correlate well with the symptoms expressed, making it particularly hard for osteoarthritis to be diagnosed early. Waiting for the condition to become severe enough to be properly diagnosed and treated is not satisfactory for those it affects.

While the study focused on the knees, osteoarthritis can occur in any joint of the body, but knees, hips and hands are the most common cases. Approximately a third of over-45s in the UK have the condition, equating to around 8.75 million people.

There is currently no cure for osteoarthritis, but the NHS highlights a number of measures that can be taken to help relieve the pain and cope with symptoms. These include regular exercise and maintaining a healthy weight; pain medication; and supportive therapies that are designed to make everyday tasks easier.

Eventually, some osteoarthritis patients undergo surgery to repair, strengthen or replace joints that have been damaged. This route is invasive, but can be necessary in the most severe cases.