Critical shoulder angle does not correlate with patient outcomes after arthroscopic rotator cuff repair

The aim of this study was to investigate the association between the critical shoulder angle (CSA) and the clinical outcomes following arthroscopic rotator cuff repair (RCR). An ambispective study was conducted in patients who underwent arthroscopic RCR and had adequate preoperative radiological shoulder studies (type A and 1 according to Suter and Henninger). Fifty-six patients with a minimum prospective follow-up of 3 years were included: 28 with a CSA >35º and 28 with a CSA <35º prior to surgery. At the follow-up, shoulder function was evaluated using the Constant-Murley score (CS), the Simple Shoulder Test (SST), the Quick DASH Scoring (QDS) and the Visual Analog Pain Score (VAS). The median CS showed no significant difference between groups: CSA <35º was 67.8 (IQR 27.8) and CSA ≥35º was 69.3 (IQR 39.6) (p=0.606). For the CSA <35º group, median SST, QDS and VAS scores were 75 (IQR 31.3); 6.8 (IQR 22.2) and 3.0 (IQR 4.8) respectively. In the CSA ≥35º group, the corresponding values were 75 (IQR 47.9); 11.3 (IQR 31.2) and 2.5 (IQR 7.0) respectively (all n.s.). Although scapular geometry has been implicated in the pathogenesis of rotator cuff disease, and both AI and CSA are simple radiographic tools, our results suggest that these parameters are not clinically relevant predictors of functional outcomes following arthroscopic RCR.