ObjectiveTo evaluate mid-term effectiveness of manipulation under anesthesia combined with arthroscopic capsular release and subacromial debridement for primary frozen shoulder.MethodsBetween January 2013 and December 2017, 33 patients of primary frozen shoulder were treated with manipulation under anesthesia combined with 360° arthroscopic capsular release and subacromial debridement. There were 10 males and 23 females, aged from 37 to 65 years, with a mean age of 50.9 years. The affected shoulder on left side in 17 cases and on right side in 16 cases. The disease duration was 6-13 months (mean, 8.4 months). Before and after operation, the visual analogue scale (VAS) score was used to evaluate the shoulder joint pain, Constant score was used to evaluate the shoulder joint function, and the flexion, abduction, and external rotation of shoulder joint were recorded. The internal rotation function was assessed based on the vertebral plane that the thumb could reach after internal rotation of the affected shoulder joint (the rank of internal rotation vertebra). X-ray film was taken to measure the distance of the subacromial space.ResultsThere was no fracture or labrum tear in all patients, and all the incisions healed by first intention. All the 33 patients were followed up 20-31 months, with an average of 24.1 months. During the follow-up, there was no complication such as wound infection and nerve injury. At last follow-up, the range of motion of shoulder flexion, abduction, and external rotation, the rank of internal rotation vertebra, the VAS score, Constant score, and subacromial space were significantly improved when compared with preoperative ones (P<0.05).ConclusionManipulation under anesthesia combined with arthroscopic capsular release and subacromial debridement can achieve a good mid-term effectiveness without complication for primary frozen shoulder.