Ohzono Kenji
Kansai Rosai Hospital, Department of Orthpaedic Surgery.
Clin Calcium. 2007 Jun;17(6):849-55.
Five criteria which showed high specificity were selected as follows. 1) collapse of the femoral head or crescent sign, 2) demarcating sclelosis in the femoral head, 3) cold in hot in bone scan, 4) band -like pattern on T1 weighted image of magnetic resonance imaging (MRI) , 5) trabecular and marrow necrosis on histology. Definite idiopathic osteonecrosis of the femoral head (ION) is diagnosed by fulfilling any two of the five criteria. Staging is judged on both AP and lateral X-ray. Stage 1 is defined as a period of no abnormality on X-ray. Stage 2is a period of demarcating sclelosis seen in X-ray. Stage 3 is a period of collapse of the head. Stage 3 is subclassified into Stage 3A when collapse is less than 3mm and 3B when collapse is 3mm or more. Stage 4 is a period of osteoarthritic changes. According to location of necrotic lesion on T1 weighted images or on x-ray, the lesions are classified into into four types. Type A lesion is defined to occupy medial one third or less of weight bearing portion. Type B lesion is defined to occupy medial two third or less of weight bearing surface. Type C1 lesion is defined to occupy more than medial two third, but not beyond acetabular edge while Type C2 lesion is defined to extend lateral to the acetabular edge.
1）股骨头塌陷或新月征；2）股骨头内界限性硬化；3）骨扫描中热区中的冷区；4）磁共振成像（MRI）T1加权图像上的带状模式；5）组织学上的小梁和骨髓坏死。符合这五条标准中的任意两条即可诊断为明确的特发性股骨头缺血性坏死（ION）。分期通过前后位（AP）和侧位X线片判断。1期定义为X线片无异常的时期。2期是X线片可见界限性硬化的时期。3期是股骨头塌陷的时期。3期又分为塌陷小于3mm的3A期和塌陷3mm及以上的3B期。4期是骨关节炎改变的时期。根据T1加权图像或X线片上坏死灶的位置，病变分为四种类型。A型病变定义为占据负重区内侧三分之一或更少。B型病变定义为占据负重面内侧三分之二或更少。C1型病变定义为占据超过内侧三分之二但未超出髋臼边缘，而C2型病变定义为延伸至髋臼边缘外侧。
