ObjectiveTo investigate the effectiveness of arthroscopic 360° capsular release for frozen shoulder.MethodsBetween April 2018 and April 2019, 42 patients with frozen shoulders were treated with arthroscopic 360° capsular release. There were 13 males and 29 females, with an average age of 52.3 years (range, 45-56 years). There were 14 left shoulders and 28 right shoulders. The disease duration ranged from 5 to 18 months (mean, 11.1 months). The main clinical symptoms were limited active and passive movement of the shoulder joint with severe pain. All patients excluded impingement syndrome and shoulder osteoarthritis. Preoperative range of motion was as follows: forward flexion (93.2±15.4)°, external rotation at side (15.9±6.0)°, external rotation at 90° abduction (18.4±9.9)°, and internal rotation reaching the greater trochanter in 5 cases, buttocks in 20 cases, S1 level in 17 cases. The visual analogue scale (VAS) score was 6.7±1.7 and the American Society of Shoulder and Elbow Surgery (ASES) score was 41.6±9.3. The active range of motion of shoulder joint, VAS score, and ASES score were recorded during follow-up.ResultsAll incisions healed by first intention, and no early complications occurred. Patients were followed up 12-24 months (mean, 15.6 months). After operation, forward flexion, external rotation at side, and external rotation at 90° abduction significantly improved when compared with preoperatively (P<0.05). The range of internal rotation restored to the level of T6-12 at 3 weeks, which was equivalent to that of the normal side at 12 months after operation (Z=–0.943, P=0.346). VAS scores decreased and ASES scores increased after operation, and the differences between pre- and post-operation were significant (P<0.05); and with time, the VAS scores and ASES scores improved further (P<0.05).ConclusionArthroscopic 360° capsular release can significantly increase the range of motion of the shoulder joint, release pain, and improve function. It is an effective method for the treatment of frozen shoulders.