Knee arthrosis is one of the most common diseases in elderly patients with varus deformity. Corrective osteotomy is one of the methods of treatment. The aim of the study is to optimize the diagnosis of varus deformities of the lower extremities in patients with gonarthrosis; improvement of the technique of surgery and postoperative control of the main reference lines and angles; evaluation of correction results; analysis of complications. Methods. Retrospective clinical study. There were 39 patients under observation, each of whom underwent simultaneous operation on both legs (78 operations in total). Osteotomies of the tibia and osteosynthesis with the Ilizarov apparatus were used in all cases. All patients underwent full-length radiography of the legs with the determination of the main reference lines and angles. Results. In all cases, it was possible to achieve the normalization of the position of the mechanical axis and the angle of orientation of the knee joint. After the operation, the sutures were not applied to the wounds in order to prevent the compartment. Correction was performed in elderly patients at the same time, in young patients - gradually. The fixation period with Ilizarov devices was 16.6 ± 3.1 weeks. Conclusion. In our study, the Ilizarov method demonstrated the possibility of accurate correction of the varus deformity of the tibia, which leads to the normalization of the position of reference lines and angles on teleroentgenograms performed after treatment.