The development of secondary deforming coxarthrosis in childhood and adolescence, as a rule, is accompanied by the formation of a pronounced deformity of the hip joint, up to ankylosis, which significantly limits the function of the lower limb and leads to early disability. In most patients, hip ankylosis develops in a vicious position with the resulting flexion-intracavity installation of the lower limb. If such a condition is encountered in childhood and adolescence, treatment currently remains debatable. Various methods are used, ranging from arthroplastic organ-preserving interventions and corrective osteotomies to joint replacement. In this report, we present a clinical case of children treated with post-infectious secondary deforming coxarthrosis with fibrous ankylosis of the hip joint in a vicious position. We applied a coherent combination of modern treatment methods: distraction in the apparatus, arthroscopy, intra-articular injections, physiotherapy, and other rehabilitation. The treatment results were evaluated over a two-year period. In this case, the rational use of a consistent set of remedial measures helped to improve joint function, socialize the patient, and postpone surgery for joint replacement for at least 2 years.