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Perthes’ disease: identifying who is at risk and why?

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What did the project achieve?

“Our results have shed new light on factors that could trigger the development of Perthes’ disease,” says Professor Michael Fagan of the University of Hull. “We hope this will ultimately lead to better ways of detecting the condition earlier and help protect children from bone damage.”

Perthes’ disease affects a child’s hip joint. Although many affected children will make a good recovery, some are left with permanent damage or can develop arthritis later in life.

The condition is poorly understood. So, Professor Fagan’s project began with a detailed review of what was already known, and from this information, the team were able to identify five possible mechanisms to investigate further.

Using X-rays of the hip from affected and healthy children, the team then identified apparent differences in the geometry of affected hip joints.

“Using advanced computer modelling, we predict that some of these differences could cause increases in pressure on different parts of the hip. However, it’s unlikely they would be enough to trigger the condition alone,” says Professor Fagan.

The researchers also developed a very detailed model that enabled them to examine the forces acting on the main blood vessels supplying the ball of the hip joint for the first time.

“Our results show that a restriction to the blood supply in the child’s hip bone could limit growth or weaken it, potentially contributing to the development of the condition,” says Professor Fagan.

The team is now continuing to investigate the effect of differences in hip joint geometry on the possible restriction of the blood supply, as they think this could help with the early identification of children who are at risk of developing the condition.

This research was completed on

Children with Perthes’ disease, an illness that affects the hip joint, are normally diagnosed when they’re between two and 14 years old, after experiencing problems such as hip pain or a limp.1 Although most children eventually make a good recovery, some develop permanent deformities or arthritis in later life. Professor Michael Fagan, of the University of Hull, is developing screening guidelines to help identify children who are at risk of getting Perthes’ disease. He’s also investigating possible preventative treatments.

What is the problem and who does it affect?

“Perthes’ disease usually begins with hip or groin pain, or a limp, but some children notice knee pain first,” explains Professor Fagan. “Over time, the hip can become stiff, and walking can become difficult and painful. Normally, just one leg is affected. If children have the condition for a long time, that leg may look shorter and thinner than the other.”

The children’s symptoms seem to result from a poor blood supply to the top of the thigh bone, which softens and breaks down. Children are typically around five years old when first diagnosed.1 More boys than girls are affected.

“The aim of treatment is to promote the natural healing process and prevent any permanent deformity or disability,” explains Professor Nicholas Clarke, joint investigator on the project. “Sometimes all that’s necessary is to monitor a child’s progress. Interventions include physiotherapy, bed rest, crutches, a plaster cast or special leg brace, and surgery. Treatment varies depending on the severity of a child’s condition, but even bed rest can be difficult for a child who is otherwise well.”

Currently, it’s not possible to predict which children will develop Perthes’ disease. By the time they’re diagnosed, their thigh bone can often be already damaged.

What is the project trying to achieve?

“We aim to develop new screening guidelines to allow early identification of children who are at risk of developing Perthes’ disease, as well as those who are in danger of suffering from particularly severe symptoms,” explains Professor Fagan. “We are also looking for ways to prevent the disease from taking hold.”

Professor Fagan and his team hope to identify the ultimate cause of Perthes’ disease, so explaining why some children develop it while others do not. They are investigating how the shape and orientation of the hip joint influence the disease process using highly sophisticated, three-dimensional computer modelling techniques. They are using the same techniques to study whether certain activities and exercises, such as horse riding or swimming, might have the potential to stop the disease from becoming established.

“We hope this study will lead to a large-scale clinical trial, designed to confirm the predictive power of our screening guidelines and the benefits of targeted activities and exercises,” explains Professor Fagan.

What are the researchers’ credentials?

Professor Fagan and his colleague, Dr Catherine Dobson, are experts in using computer models to understand how our bones respond to the forces they’re subjected to as we move around. Professor Nicholas Clarke is a consultant surgeon with experience of caring for children with Perthes’ disease and a strong track record in research in this area.



  1. Perry DC et al. The epidemiology and etiology of Perthes disease. Orthop Clin N Am 2011; 42:279-83.


Project Leader Professor Michael J Fagan BSc PhD CEng CITP MBCS
Project Team Professor Nicholas MP Clarke FRCS ChMDr Catherine A Dobson BSc PhD PGCHE FHEA
Project Location Department of Engineering, University of Hull in conjunction with University Orthopaedics, Human Development and Health, University of Southampton and Southampton General Hospital
Project duration 3 years
Date awarded 15 November 2012
Project start date 1 September 2013
Project end date 31 December 2016
Grant amount £139,348
Grant code GN2076


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