Osteoarthritis (OA) is a growing problem around the world. An estimated 10% to 15% of all adults over the age of 60 have some degree of OA, and the condition is becoming more prevalent due to population ageing and an increase in related factors such as obesity.

Figures from the United Nations suggest that by 2050, 130 million people will suffer from OA worldwide, of whom 40 million will be severely disabled by the disease.

But a new 3D imaging analysis technique offers hope of earlier diagnosis and could lead to improved treatment.

The technique, which detects tiny changes in arthritic joints, was developed by a team of engineers, physicians and radiologists led by the University of Cambridge.

According to the researchers, their breakthrough could enable greater understanding of how osteoarthritis develops and allow the effectiveness of new treatments to be assessed more accurately, without the need for invasive tissue sampling.

At the moment, OA is often diagnosed when x-ray images show a narrowing of the space between the bones of the joint due to a loss of cartilage. However, x-rays do not have enough sensitivity to detect subtle changes in the joint over time.

"In addition to their lack of sensitivity, two-dimensional x-rays rely on humans to interpret them," explained lead study author Dr Tom Turmezei from Cambridge University's Department of Engineering. "Our ability to detect structural changes to identify disease early, monitor progression and predict treatment response is frustratingly limited by this."

To get a more detailed picture of the joint, the technique developed by Turmezei and his colleagues uses images from a standard computerised tomography (CT) scan. Although this type of scan isn't normally used to monitor joints, it produces detailed images in three dimensions.

The semi-automated technique, called joint space mapping (JSM), analyses the CT images to identify changes in the space between the bones of the joint -- a recognised surrogate marker for osteoarthritis.

Tests on human hip joints from bodies that had been donated for medical research revealed that, compared with the current 'gold standard' of joint imaging with x-rays, the new technique was at least twice as good at detecting small structural changes.

"Using this technique, we'll hopefully be able to identify osteoarthritis earlier, and look at potential treatments before it becomes debilitating," said Dr Turmezei, who is now a consultant at the Norfolk and Norwich University Hospital's Department of Radiology. "It could be used to screen at-risk populations, such as those with known arthritis, previous joint injury, or elite athletes who are at risk of developing arthritis due to the continued strain placed on their joints."

As CT can now be used with very low doses of radiation, it can be safely used more frequently for the purposes of ongoing monitoring, the researchers noted.

When combined with 3D statistical analysis, the JSM algorithm could also be used to speed up the development of new treatments, Dr Turmezei added.

The findings of the study have been published in the journal Scientific Reports.