Ficat classification of osteonecrosis
The Ficat classification of osteonecrosis is based on radiographic findings. In 1985 Dr Ficat published a modified version of his initial classification in 1980:
Stage 0
- preclinical and preradiographic
- diagnosis is suspected in one hip when the other has a definite disease - this is the stage of the truly “silent hip”
Stage I
- earliest clinical manifestation of the syndrome which is pain in almost 50% of patients
- limited movement of hip joint in all direction on physical examination
radiographs are normal or, at most, show only minor changes such as subtle loss of clarity with poor definition or blurring of the trabecular pattern, patchy osteoporosis in comparison with the opposite side, but the changes are not really significant
Stage II
- extends over several months or even much longer
- clinical signs persist, or worsen
- radiographs show changes in the trabecular pattern of the femoral head:
- sclerosis: may be diffuse, localized, or in a linear arc which is concave superiorly
- lucency: may also be generalized or small cysts in the head, usually at some distance from the joint space
- mixed form: including both sclerosis and cysts is sometimes seen
Stage III
- pathognomonic imaging features
- crescent line: due to a subchondral fracture
- out of round appearance: segmental flattening of the femoral head
paradoxically and because of the limited size of the sequestrum the joint space is preserved or even increased
Stage IV
- terminal phase of the necrotic process
- hip movement is progressively diminished until only a small range of flexion remains
- the radiographic picture is of osteoarthritis superimposed on a deformed femoral head which is characterized by progressive loss of articular cartilage and the development of acetabular osteophytes
See also
