Hip Preservation Experience of Avascular Necrosis of Femoral Head According to China-Japan Friendship Hospital Classification

Objective To sum up staging treatment experiences of hip preservation for avascular necrosis of the femoral head (ANFH) according to China-Japan Friendship Hospital Classification (CJFH Classification). Methods The literature about hip preservation of ANFH was extensively reviewed, and a staging treatment method for ANFH was set up base on CJFH Classification and the 28 years of clinical experience in this research group. Results According to CJFH Classification, the ANFH can be rated as types M, C, and L. And the type L is rated as L1, L2, and L3 subtypes. The staging treatment method for ANFH based on CJFH Classification is set up. Conservative treatment was selected for CJFH-M patients because the necrotic area is small and in the medial non-weight-bearing area. Minimally invasive sequestrum clearance, impacting bone graft, and supporting allogenic fibular graft is selected for CJFH-C patients because the necrotic area is also small and in the lateral non-weight-bearing area. If patients are in CJFH-L1, normal bone area is less than 1/3 on hip abduction radiograph, the sequestrum clearance and impacting bone graft via surgical hip dislocation approach can be selected. If patients are in CJFH-L1, normal bone area is more than 1/3 on hip abduction radiograph, the transtrochanteric curved varus osteotomy can be selected. The rotational osteotomy on the base of femoral neck via surgical hip dislocation approach is for CJFH-L2 patients. Total hip arthroplasty via direct anterior approach is for CJFH-L3 patients. Conclusion The staging treatment method for ANFH according to CJFH Classification has good short-term effectiveness. But the long-term effectiveness needs further follow-up.