Objective To investigate the clinical efficacy of arthroscopic double Endobutton plate internal fixation in the treatment of acute acromioclavicular joint dislocation.Methods A retrospective case series study was performed to analyze the clinical data of 32 patients with Rockwood type Ⅲ or Ⅴ acute acromioclavicular joint dislocation admitted to Foshan Hospital of TCM from May 2015 to February 2018.There were 26 males and six females,aged 22-56 years [(37.7 ± 1.6)years].There were 22 patients with Rockwood type Ⅲ and 10 patients with type Ⅴ.The duration from injury to operation was 2-5 days.All patients were treated with arthroscopic double Endobutton plate internal fixation for coracoclavicular ligament reconstruction.The operation time,hospitalization time,and postoperative shoulder joint braking time were recorded.The shoulder joint function was evaluated by the Constant-Murley score (CMS),visual analogue scale (VAS),American shoulder and elbow surgeons (ASES) score,University of California Los Angeles (UCLA) score and simple shoulder test (SST) before operation and at the last follow-up.Meanwhile,complications such as infection,loosening and joint dislocation were recorded.Results All patients were followed up for 8-48 months [(27.8 ± 11.6) months].The operation time was 48-93 minutes [(65.0 ± 24.6) minutes],the hospitalization time was 3.2-10 days [(6.5 ± 2.6)days],and the postoperative braking time was 21-35.3 days [(28.2 ± 7.1)days].All patients had a grade A healing of surgical incision.The VAS was decreased from preoperative (5.7 ±2.5)points to (1.2 ±0.8)points at the last follow-up (P ＜0.01);CMS wasvincreased from preoperative (29.3 ± 3.4) points to (93.2 ± 2.1) points at the last follow-up (P ＜0.05);ASES score was increased from preoperative (28.9 ± 10.1) points to (95.7 ± 5.6) points at the last follow-up (P ＜ 0.05);UCLA score was improved from preoperative (11.6 ± 2.8) points to (34.2 ±1.5)points at the last follow-up (P ＜0.05);SST score was improved from preoperative (3.5 ±1.2)points to (9.7± 1.4)points at the last follow-up (P ＜ 0.O1).The incidence of intraoperative and postoperative complications was 16％ (5/32).In two patients,the surgery was changed to U shape fixation circulating the coracoid base due to the coracoidbone tunnel cutting out.One patient was found to have insufficient reduction and received the acromioclavicular joint operation.One patient had reduction loss due to the clavicle button collapsing,and one patient had excessive reduction.Conclusions For Rockwood type Ⅲ or Ⅴ acute acromioclavicular dislocation patients,arthroscopic double Endobutton plates for coracoclavicular ligament reconstruction has the advantages of less intraoperative trauma,quick recovery and satisfactory clinical result.However,the incidence of intraoperative and postoperative complications is relatively high,and indications should be strictly controlled.