To compare the clinical efficacy between the modified double Endobutton technique and the classical double Endobutton technique on the treatment of Rockwood type III acromioclavicular joint dislocation or greater.

Twenty-six patients with Rockwood type III injury and above this level were randomly treated with the modified double Endobutton technique (12 patients) or the classical double Endobutton technique (14 patients) from Jan 2015 to Jan 2017. The operation time, bleeding volume, the incision length, the incidence of post-operative compilations and recovery of the shoulder function of all patients were recorded and compared . The complications and postoperative joint functions were compared using chi-square test. The length of incision, intraoperative blood loss and operation time were measured by t-test.

Compared with the classic group, the length of the incision was similar in the modified group, and the incidence of complications were basically the same as those in the modified group. Although the function recovery of the shoulder joint was better in the classical group, the duration of surgery (t=6.18, P<0.01)and blood loss, which was(48.7±6.5)ml in the modified group were significantly less than (57.8±7.7)ml in the classic group (t=6.01, P<0.01). The differences were statistically significant between the two groups.

The improved double-button plate technique has less trauma, firm fixation, convenient operation, significantly reduced intraoperative blood loss, and significantly shorter operative time, but it does not improve shoulder function in the short term better than the classic group.