Objective To investigate the effectiveness of the suture anchor technique without knots for reconstruction of the anterior talofibular ligament (ATFL) combined with the reinforcement of the inferior extensor retinaculum in treating chronic lateral ankle instability (CLAI). Methods The clinical data of 31 patients with CLAI who were admitted between August 2017 and December 2023 and met the selection criteria were retrospectively analyzed. There were 18 males and 13 females, with an age range from 20 to 48 years (mean, 34.61 years). All patients had a history of repeated ankle sprain, with a disease duration of 6-18 months (mean, 9.65 months). The anterior drawer test and inversion stress test were positive, and tenderness was present in the ligament area. Stress X-ray films of the ankle joint showed a talar tilt angle of (10.00±2.78)° and an anterior talar displacement of (9.48±1.96) mm on the affected side. MRI revealed discontinuity, tortuosity, or disappearance of the ATFL structure. Preoperatively, the visual analogue scale (VAS) pain score was 5.2±2.1, and the American Orthopaedic Foot and Ankle Society (AOFAS) score was 62.9±7.1. All patients underwent arthroscopic debridement of the ankle joint followed by reconstruction of the ATFL using the suture anchor technique without knots combined with reinforcement of the inferior extensor retinaculum. Postoperatively, pain and function were assessed using the VAS and AOFAS scores. Stress X-ray films were taken to measure the talar tilt angle and anterior talar displacement to evaluate changes in ankle joint stability. Patient satisfaction was assessed according to the Insall criteria. Results All 31 surgeries were successfully completed. One case had wound exudation, while the remaining surgical incisions healed by first intention. Two cases experienced numbness on the lateral aspect of the foot, which disappeared within 1 month after operation. All patients were followed up 15-84 months (mean, 47.23 months). No complications such as anchor loosening, recurrent lateral ankle instability, superficial peroneal nerve injury, rejection reaction, or wound infection were observed postoperatively. The anterior drawer test and inversion stress test were negative at 3 months after operation. Stress X-ray films taken at 3 months after operation showed a talar tilt angle of (2.86±1.72)° and an anterior talar displacement of (2.97±1.32) mm, both of which were significantly different from the preoperative values (t=12.218, P<0.001; t=15.367, P<0.001). At last follow-up, two patients had ankle swelling after exercise, which resolved spontaneously with rest; all 31 patients returned to their pre-injury level of sports or had no significant discomfort in daily activities. At the last follow-up, twenty-five patients were pain-free, 4 had mild pain after exercise, and 2 had mild pain after walking more than 2 000 meters. The VAS score at the last follow-up was0.8±0.9 and the AOFAS score was 91.6±4.1, both of which were significantly different from the preoperative scores (t=10.851, P<0.001; t=−19.514, P<0.001). According to the Insall criteria, 24 patients were rated as excellent, 4 as good, and 3 as fair, with a satisfaction rate of 90.3%. Conclusion The suture anchor technique without knots for reconstruction of the ATFL combined with reinforcement of the inferior extensor retinaculum provides satisfactory mid-term and short-term effectiveness in treating CLAI.