Background. Anterior cruciate ligament rupture is the most common knee joint injury, especially in young people with a healthy and active lifestyle. The concept of quality of life has been dynamically developing. The scope of its application is expanding in various fields of medicine to provide a comprehensive assessment of treatment and rehabilitation efficacy.Objective — to assess the feasibility of complex individual physical rehabilitation of patients after early and delayed arthroscopic reconstruction of the anterior cruciate ligament (ACL).Methods. Open simple non-randomized trial enrolled 834 patients with the anterior cruciate ligament rupture of the knee joint. In the first group (431 patients), ACL plastic surgery was performed in the early stages — between weeks 2 and 6. In the second group (403 patients), ACL reconstruction was performed in the later stages — from week 7 to 1 year, inclusive. Each group was divided into two subgroups — the main one, in which restorative treatment and comprehensive individual rehabilitation were carried out, and the control group, with rehabilitation treatment in accordance with the standards of postoperative treatment. The study was conducted in Traumatology, Orthopedics and Medical Rehabilitation Unit of Clinical Hospital No. 1. Patients were included in the trial from 2016 to 2021. The follow-up period for each patient was one year. Statistical data processing was performed by means of Statistica 12.0 (StatSoft, Inc., USA). Independent samples were compared using non-parametric criteria: Mann — Whitney U-test and Wilcoxon T-test.Results. No statistical differences were found in the distribution according to gender, age and body mass index. A comparative analysis of scale medians of Medical Outcomes Study 36Item Short-Form Health Survey (MOSSF-36), conducted in patients before surgery, revealed no statistically significant differences ( p>0.05) between the main and control subgroups in both groups. Analyzing medians before ACL reconstruction showed a significant decrease in comparison with population studies ( p < 0.0001, Mann — Whitney U-test). The analysis of physical and mental component summaries via MOSSF-36 revealed statistically significant differences in the effectiveness of treatment of patients in 1 year after ACL plastic surgery and complex individual rehabilitation. Thus, in the main subgroups, the values of treatment efficacy medians were significantly higher than in the control ones, regardless of the timing of ACL plastic surgery ( p < 0.001, Mann — Whitney U-test). The results testify to higher median efficacy values in patients of the main subgroup of group 1 than in other subgroups ( p < 0.001, Mann — Whitney U-test). The study of correlative relationships demonstrated a stronger relationship between the medians of physical and mental component summaries in the main subgroup of the first group (correlation coefficient = 0.76), if compared to the main subgroup of the second group (coefficient = 0.67).Conclusion. The study testified to the treatment efficacy proved using the scales of physical and mental component summaries. They demonstrated more significant treatment efficacy one year after arthroscopic ACL reconstruction and individual rehabilitation in the main subgroup of group 1 than in the other subgroups.