Ficat and Arlet Stages of Femoral Head Necrosis Stage I: normal x-ray performance Stage II: normal femoral head shape, but significant bone repair (cystic degeneration and osteosclerosis) Stage III: subchondral bone collapse (flattening of the femoral head) Stage IV: joint space narrowing, joint collapse and secondary degeneration of the acetabulum (cystic degeneration, marginal bone formation, cartilage destruction) Zhang Chi, Department of Orthopedics, Zhongshan Hospital, Fudan University Treatment Options: Stage I: medullary core decompression Stage II: medullary core decompression, bone graft, osteotomy Stage III: bone graft, total hip replacement Stage IV: total hip replacement, with ceramic-to-ceramic interface for younger patients