[Critical shoulder angle as a predictor of severity in rotator cuff injuries].

Introduction: the connection between a critical shoulder angle (CSA) greater than 35° and the presence rotator cuff tears (RCT) is well known. However, it remains unidentified if there is an association between a higher CSA value and the presence of more severity RCT.

Material and methods: cross-sectional, descriptive, observational, prospective and analytical study in which patients with RCT had their CSA evaluated by imaging and the degree of the RCT by arthroscopy. Four groups were formed (without lesion; partial lesion; complete lesion; massive lesion) and were compared using ANOVA parametric statistics. The association between RCT and CSA was studied by rho Spearman coefficient.

Results: 71 patients were studied, 15 without RCT (CSA of 34.13 ± 0.98), 17 with partial lesion (CSA of 36.00 ± 1.15), 22 with complete lesion (CSA of 40.77 ± 0.69) and 17 with massive lesion (CSA of 41.53 ± 0.68). No significant statistical difference was found between the CSA of the groups without lesion and partial lesion (p = 0.486; 35°) but there was a difference between the groups with complete and massive lesion (p = 0.000 and p = 0.001; 35°). A significant positive association was found between CSA and RCT (rho = 0.605, p = 0.000).

Conclusions: an CSA above 35° is associated to complete and massive RCT and it works as a predictor of severity for these lesions.