The Critical Shoulder Angle as a Prognostic Factor in the Arthroscopic Repair of Chronic Rotator Cuff Tears

Background: Rotator cuff tears, a prevalent pathology with significant functional impact, primarily find their therapeutic approach in arthroscopic repair. The long-term success of this intervention is modulated by various factors, among which shoulder morphology stands out. In this context, the critical shoulder angle (CSA) has gained relevance as a potential predictor of postoperative prognosis. Objectives: To determine if the CSA influences the need for reoperation after retears and functional outcomes following the arthroscopic repair of chronic rotator cuff tears. Methods: A retrospective cohort study has been conducted, which includes 74 patients (between 47 and 86 years old, mean age of 58.85 ± 2.21 years) who underwent arthroscopic shoulder surgery for the repair of chronic rotator cuff tears by the traumatology service of a tertiary level hospital in the period between 2009 and 2022, to study variables such as the appearance of complications, reoperation, and functional outcomes. Results: Patients with a CSA greater than 40° represent 56.75% (n = 42). Functional improvement was achieved in 59.52%, in contrast to 40.48% of patients who did not obtain significant functional improvement (OR = 1.470; 95% CI = 1.009-2.141). The reoperation rate in this group was 21.4% (n = 9) (OR = 1.562; 95% CI = 1.085-2.249). Conclusions: This study provides statistically significant evidence that a high CSA (>40°) behaves as a risk factor for the reoperation rate and poorer functional outcomes after the arthroscopic repair of chronic rotator cuff tears.