ObjectiveTo investigate the short-term effectiveness of arthroscopic assisted double Endobutton “8” buckle fixation in the treatment of Rockwood Ⅲ type acute acromioclavicular joint dislocation.MethodsThe clinical data of 12 patients with Rockwood Ⅲ type acute acromioclavicular joint dislocation who were treated with arthroscopic assisted double Endobutton “8” buckle fixation between June 2016 and June 2019 were analyzed retrospectively. There were 8 males and 4 females, with an average age of 47.0 years (range, 36-58 years). There were 4 cases of left shoulder and 8 cases of right shoulder. The causes of injury included traffic accident injury in 7 cases and falling injury in 5 cases. The average time from injury to operation was 5.0 days (range, 3-14 days). Before operation and at last follow-up, the shoulder joint activity was recorded; the improvements of function and pain were evaluated by Constant score and visual analogue scale (VAS) score, respectively; the reduction was evaluated by measuring the coracoid spacing of the affected side on the anteroposterior X-ray film of shoulder joint.ResultsAll 12 cases were followed up 6-36 months, with an average of 20.6 months. All the incisions healed by first intention. There was no complications such as clavicle and coracoid fractures and Endobuton displacement. At last follow-up, the range of motion of the abduction improved from preoperative (77.5±4.5)° to (162.5±6.5)°, the range of motion of forward flexion improved from (84.1±5.2)° to (169.5±5.8)°, the Constant score improved from 42.5±2.3 to 92.4±2.3, the VAS score improved from 5.4±0.8 to 0.6±0.5, and the coracoid spacing reduced from (20.5±1.4) mm to (9.2±0.6) mm, all showing significant differences (P<0.05).ConclusionArthroscopic assisted double Endobutton “8” buckle fixation for the treatment of Rockwood Ⅲ type acute acromioclavicular joint dislocation is safe, less invasive, and quicker recovery. It can effectively alleviate shoulder pain, significantly improve the mobility of the shoulder joint, and achieve good short-term effectiveness.