The problem of diagnosis and treatment of chronic anterior-posterior instability of the knee joint in multi-ligamentous injuries remains relevant, both medically and socially. Conservative treatment of patients with this pathology is ineffective due to severe instability and gross violation of the biomechanics of the knee joint. Currently, there is no consensus on the tactics of surgical treatment of this disease, and on the method of plastic replacement of the lost ligamentous apparatus. Objective. To evaluate the clinical results of the modified technique of arthroscopic plastic surgery of both cruciate ligaments of the knee joint. Patients and methods. Based on previous anatomical studies, the authors formulated the basic principles of safe formation of bone tunnels in simultaneous arthroscopic plastic surgery of the anterior (PKS) and posterior (ZKS) cruciate ligaments. An original method of surgery aimed at minimizing the risk of injury to the popliteal artery during the formation of the tibial bone tunnel is proposed. In the period from 2010 to 2017, the Department of endoscopic surgery treated 20 patients with damage to the SCS and SCS using this technique. The results were evaluated 6 and 12 months after surgery. Clinical examination, IKDC and Lisholm-Gillqist questionnaires and the visual analog pain assessment scale (VAS) were used to evaluate clinical results. Results. The average score on the IKDC questionnaire was 34.16±13.31 points before surgery, and 34.89±18.37 points on the lisholm — Gillqist questionnaire. 6 months after surgery — 58.75±6.38 and 69.78±14.10 points according to IKDC and Lisholm—Gillqist, respectively, which is statistically significant (p<0.05) higher than before surgery. A year after the operation, the positive dynamics was observed even more clearly (p<0.01): 76.83±9.26 and 82.00±6.38 points, respectively. The final result of the evaluation according to the IKDC Protocol: 11 (55.0%) patients were assigned to group A (good result), 6 (30.0%) to group B (close to good result), 2 (10.0%) to group C (satisfactory result) and 1 (5.0%) patient to group D (unsatisfactory result). Conclusion. The obtained clinical results allow to evaluate the proposed method as effective. In this case, the method of forming bone tunnels has a number of advantages compared to the classical technique, including minimizing the risk of intraoperative damage to the structures of the popliteal neurovascular bundle.