Avascular necrosis of the femoral head in sickle cell disease. An integrated classification.

Avascular necrosis of the femoral head (ANFH) is one of the crippling complications of sickle cell disease (SCD), and to date there is no classification that could identify patients in the early phase of the necrosis. Based on the experience of 66 ANFH in 43 patients with SC hemoglobinopathy, the necrosed hips were classified into four grades, Grade I to Grave IV, based on patient history, clinical evaluation, and radiologic examination. In Grade I, the patient complains of the mildest symptoms with minimal clinical signs and radiologic changes. The most severe form, Grade IV, is where the findings are unbearable pain with disability and marked roentgenographic evidence of osteonecrosis. This classification identifies patients in Grade I and II, which, with early diagnosis and proper management, could delay further deterioration of the necrosed femoral head.