Does anterior arthroscopic acromioplasty modify critical shoulder angle

INTRODUCTION: Critical shoulder angle (CSA) is measured on AP view in neutral rotation as the angle subtended by the tangent to the glenoid and the lateral edge of the acromion. CSA >35 degrees is a risk factor for primary rotator cuff tear and iterative tear after cuff repair. The aim of the present study was to assess change in CSA following arthroscopic anterior acromioplasty. HYPOTHESIS: CSA is decreased by arthroscopic anterior acromioplasty. MATERIAL AND METHOD: A single-center retrospective descriptive observational study included patients undergoing arthroscopic acromioplasty between January 2016 and December 2017, for whom strictly AP pre and postoperative radiographs were available. Patients with history of surgery, fracture or dislocation in the same shoulder were excluded. RESULTS: One hundred and two patients were included; mean age, 50.5 years (range, 23-82 years). Mean preoperative CSA was 34.7+/-4.4 degrees (range, 26-48 degrees ) and postoperative CSA 31.7+/-3.7 degrees (range, 23-40 degrees ) (p 35 degrees ), the values were 38.9+/-2.8 degrees (36-48 degrees ) and 34.4+/-3.2 degrees (28-40 degrees ) (p 35 degrees ) were not corrected, with risk of rotator cuff tear. CONCLUSION: Anterior arthroscopic acromioplasty significantly reduced CSA overall, notably in case of high CSA. LEVEL OF EVIDENCE: IV, retrospective study.