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