Classification of ischemic necrosis of the femoral head
Steibery’s classification was accepted by the American Academy of Orthopaedic Surgeons, Hip Section in 1992 and is as follows.
Stage 0: normal radiographs, normal bone scan and MRI or non-diagnostic
Stage I: normal radiographs, but abnormal bone scan and MRI
A- Mild (less than 15% of the femoral head is involved)
B- Moderate (15%-30% femoral involvement)
C- Severe (greater than 30% femoral involvement)
Stage II: translucent or sclerotic changes of the femoral head
A- Mild (less than 15% femoral involvement)
B- Moderate (15%-30% femoral involvement)
C- Severe (greater than 30% femoral involvement)
Stage III: subchondral bone collapse (crescent sign) without femoral head changes
A- Mild (less than 15% of the articular surface with less than 2mm of subsidence)
B- Moderate (15%-30% of the articular surface is involved)
C- Severe (greater than 30% articular surface involvement)
Stage IV: femoral head deformation and subluxation
A- Mild (less than 15% articular surface involvement, subsidence less than 2mm)
B- Moderate (15%-30% articular surface involvement, 2-4mm subsidence)
C- Severe (greater than 30% articular surface involvement, subsidence greater than 4mm)
Stage V: joint surface space narrowing or and acetabular changes
A- mild (average severity of femoral head involvement as in stage IV)
B- Moderate (determined similar and estimated to have)
C- Severe (acetabular involvement)
Stage VI: degenerative arthritic changes
For ischemic necrotic disease of the femoral head, it is important to define the size of osteonecrosis to decide the treatment and prognosis. The most important feature of Steiberg staging is the objective determination of the extent of necrosis, although this staging is more cumbersome than the various previous staging methods.
Marous staging method.
Stage I: the hip is asymptomatic, with no manifestation or slight density increase (dotted density increase) on x-ray.
Stage II: still asymptomatic or mild, with increased density on X-ray and no head collapse.
Stage III: mildly symptomatic, with subchondral fracture or crescentic sign, generally more fan-shaped fracture, crescentic sign is rare.
Stage IV: hip pain, paroxysmal or persistent claudication and functional impairment, head flattening or osteonecrosis.
Stage V: significant pain, dead bone rupture, narrowing of the joint space, and more sclerotic bone density.
Stage VI: severe pain, some pain is reduced compared with stage V, but the femoral head is hypertrophied and deformed, semi-dislocated, and the acetabulum is not smooth, or even sclerotic and hyperplastic.