OBJECTIVES: To analyze the return to the sport and the level of sports practice in a longitudinal cohort of athletes treated with osteotomy around the knee. METHODS: Active athletes who underwent osteotomy or knee surgery to treat knee osteoarthritis were included, and their data was collected retrospectively. The primary outcomes were maximum physical activity level before and after the surgery (Tegner score), time to return to maximum activities and reoperation. RESULTS: Twenty athletes with a mean age of 33 years at the time of surgery (standard deviation 8.9 (SD)) and with a mean follow-up of 9.8 years (SD 4) were included. The mean maximum Tegner score achieved before surgery was 8.6 (SD 1.4). Nineteen patients returned to sports (95%), and 13 returned to the same prior level (65%). The median time to return to the maximum level was 13 months (mean 17.9, SD 12.4). The mean maximum postoperative Tegner score was 7.5 (SD 2.0), slightly lower than the maximum achieved before surgery (mean difference:1.1, CI:0.2-1.9, P=0.026). CONCLUSION: The results of this study suggest that, after osteotomies around the knee, athletes present a high rate of return to sports activities, with most returning at the same level as before the surgery.