Radiographic Findings
• Crescent Sign
• Snowcapping
• Areas of lucency
• Flattening of joint surface
Crescent Sign
Luscent areas
Flattening of joint surface
Snowcapping
Luscent areas
Flattening
AVN Classification (FICAT System)
Stage I conventional radiograph is normal, but MRI or radionuclide imaging findings will confirm AVN
Stage II cystic and sclerotic changes are seen on conventional radiographs
Stage III crescent sign is seen
Stage IV flattening of the femoral head, narrowing of the hip joint, severe joint destruction