Diagnosis and classification of avascular necrosis of the hip

Plain radiographs and MRI scanning are the most useful imaging studies for the diagnosis and treatment of avascular necrosis of the femoral head. Because treatment of early avascular necrosis may postpone or avoid joint replacement surgery, early diagnosis and staging are important aspects of the disease. Because it is easily understood and clinically relevant, the Ficat classification is currently the most widely used classification scheme. While the four stages of the Ficat classification are straightforward, it should be noted that it does not take into account the important factor of the size of the lesion.