The paper proposes and substantiates an arthroscopic classification of pathological processes in the hip joint associated with avascular necrosis of the femoral head (ANFH). In 2018–2022, the authors developed and advanced to the clinic “Method of minimally invasive two-stage decompression with bone alloplasty” (RF patent No. 2691543), which involved diagnostic and therapeutic arthroscopy of the hip joint as its first stage. The international ARCO classification (Association Research Circulation Osseous classification) was chosen as the prototype for the invention. The endoscopic view was recorded and compared with the data of radiological research methods (radiography, spiral CT and MRI). The revealed changes are characterized by the absence of pronounced pathological signs at stages 0, I according to ARCO, which testifies to the possibility of arthroscopic intervention only for the purpose of joint cavity drainage. Further development of necrosis is accompanied by the formation of cartilage flaps, cartilage defects, acetabular labrum tears, lysis of the ligament of the femoral head with the subsequent development of arthrosis, and, therefore, requires a combined approach.