(1) According to the classification of bone graft materials: a. According to the different sources of bone graft materials, they are divided into: autologous bone graft, allogeneic bone graft, and artificial bone graft; b. According to the different materials of bone tissue, they can be divided into cancellous bone graft or cortical bone graft; (2) The above bone graft materials can be implanted into the femoral head through different paths around the femoral head. (2) The above-mentioned bone graft materials can be implanted into the femoral head through different pathways around the femoral head, mainly through four pathways: a. The femoral head through the greater trochanter: b. The femoral head through the femoral neck: c. The femoral head through the craniocervical junction; d. The femoral head through the cartilage of the articular surface of the femoral head. Except for path a, which enters the femoral head through the greater trochanter without entering the joint, the other three paths, b, c and d, all require incision of the hip joint and entry into the femoral head through the joint. Therefore, the latter three routes may affect the postoperative joint function and may even destroy the original blood flow of the femoral head.