Perthes Disease occurs most commonly in five-year-old male patients, who present with a insidious onset of a limp and a painful hip. On examination, the hip is stiff and painful. These patients commonly present with knee pain and this should be watched for. The disease process involves bone death of the femoral epiphysis (the most distal bone section of the femoral head) – the cause of this problem is unknown. It is the only type of avascular necrosis, which recovers over time. This has important treatment implications – the earlier the problem is diagnosed, the earlier the patient may be managed with containment and elimination of weight-bearing (it remains controversial whether surgical management of Perthes disease is ever indicated). Once resolution of the avascular necrosis has occurred, the patient may once again begin walking on the hip.
The only long-term determinants of outcome in this condition are the shape of the femoral head and its congruity with the acetabular cup of the hip. The longer a patient remain symptomatic and continues to walk on the hip, the more likely it is that significant collapse of the head will occur and that the patient will therefore developed a poorer outcome, which often leads to early onset osteoarthritis in adulthood.
