摘要股骨头坏死是股骨头血供受损或中断，导致骨髓成分及骨细胞死亡，随后发生修复，继而导致股骨头结构改变甚至塌陷的系列病理改变与临床表现。国际骨循环研究协会（Association Research Circulation Osseous，ARCO）制订的股骨头坏死分期在指导治疗、判断预后、评估疗效方面得到广泛应用。2019年11月，关节外科杂志（Journal of Arthroplasty）在线发表了韩国学者Kyung-Hoi Koo牵头的专家组制订的股骨头坏死分期标准修订版。这是自1994年以来国际骨循环研究协会分期的重大改变。修订后的ARCO分期为四分期体系，特点包括：取消了0期分期，确定Ⅰ和Ⅱ期为塌陷前病变，Ⅲ期细化为早、晚期，X线片出现关节间隙变窄、髋臼改变和关节破坏的骨关节炎表现归入Ⅳ期。这次ARCO分期的改良，可谓化繁为简，却没能做到执简驭繁，对疾病治疗指导和预后判断的效果和意义有待进一步验证。

abstractsOsteonecrosis of femoral head (ONFH) has a series of pathological changes and clinical manifestations, including damaged or interrupted blood supply of the femoral head and death of bone marrow and osteocytes. Although subsequent repairing was observed in ONFH, it leads to structural changes or even collapses ultimately. The classification system established by the Association Research Circulation Osseous (ARCO) has been widely used in guiding treatment, estimating prognosis, and evaluating efficacy. In November 2019, 2019 revised version was published on the Journal of Arthroplasty that defined staging system for ONFH developed by an expert group led by Kyung-Hoi Koo, a Korean scholar. It has a great change of ACRO staging system since 1994. The revised ARCO staging system has four-stage system. The features of revised ARCO staging system includes the following items, abolition of stage 0, defining stage I and II as pre-collapse lesions, subgrouping stage III as early and late stage, X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes and joint destruction classified as stage IV. The revised ARCO staging system simplifies the complexity of the system, but not handles the complexity. Further verification of efficacy and significance of the revised staging system are still required in term of guiding treatment and estimating prognosis.