Critical shoulder angle (CSA)>35° correlates significantly with primary rotator cuff tear and re-tear after repair. Acromial axial orientation varies between individuals. The present study aimed to assess the impact of strictly anterior acromioplasty on CSA.

CSA is reduced by arthroscopic anterior acromioplasty.

A single-center retrospective study included patients receiving isolated arthroscopic acromioplasty between January 2016 and December 2017. Exclusion criteria comprised history of surgery and fracture or dislocation of the shoulder. Pre- and post-operative AP shoulder radiographs were taken. The angle subtended by a line between the inferior and superior edges of the glenoid and a line between the inferior edge of the glenoid and the most lateral point on the acromion was measured.

One hundred and two patients were included: mean age, 50.5±10.1 years (range, 23–82 years). Mean CSA was 34.7±4.4° (range, 26–48°) preoperatively and 31.7±3.7° (range, 23–40°) postoperatively (p<0.001). In the group with CSA >35°, the decrease was significant: 34.4±3.2° (range, 28–40°) versus 38.9±2.8° (range, 36–48°) (p<0.001), with 64% CSA <35° after isolated anterior acromioplasty.

CSA was decreased by arthroscopic acromioplasty. However, in 36% of cases with preoperative CSA >35°, CSA was not normalized.

Anterior arthroscopic acromioplasty significantly reduced CSA in the overall population, and especially in case of high CSA.

IV; retrospective study.