There are several long-term studies in the literature indicating that patients who have Perthes’ disease diagnosed in childhood do eventually develop osteoarthritis of the hip perhaps 10-15 years before retirement age. This would be the most optimistic outcome for Perthes’ disease. Many of the children referred to tertiary referral centres and major orthopaedic units, by definition, probably have a prognosis worse than this.
Increasing numbers of young adults are presenting to orthopaedic hospitals in their 20s and 30s, aware of leg shortening, limited movement and intolerance of the more popular and vigorous physical activities. From the x-rays they are usually discovered at this age to have a reasonably well preserved joint space, with (combinations of) shortening of the neck of the femur, high riding of their greater trochanter and a shallow hip socket – acetabular dysplasia. A small minority of patients in their 20s and 30s present with frank osteoarthritis – these patients will need to be treated with hip resurfacing or hip replacement, according to what is possible.
In patients who have a well preserved joint space, following careful x-rays, CT scans and/or MRI scans, it is usually possible to define the anatomical abnormality fairly accurately. Each abnormality can be dealt with on its own merits and surgically restored to a more normal configuration. (See also Perthes’ in children).