Does bony morphology of the shoulder affect rotator cuff retear rates? A 24-year retrospective cohort of rotator cuff repairs

Background: Rotator cuff tears can result in pain which can be debilitating. The etiology of failed repair or retears is multifactorial. Multiple risks factors were proposed, with critical shoulder angle (CSA) being one of the factors of emerging interest. Other radiological parameters including glenoid inclination (GI), lateral acromial angle (LAA), and acromial index (AI) were also suggested for a possible correlation. Methods: A retrospective review of 397 rotator cuff repairs on January 1, 2000 to December 31, 2023 recruited from two major hospitals was carried out. Primary outcome measure of radiographic shoulder angles (CSA, GI, LAA, and AI) was measured. Results: There is no statistical difference in radiographic shoulder angles measured in the rotator cuff retear group and the no retear group. Retear patients were more likely to have Goutallier grade 3 and 4 (p = 0.01). Goutallier grade 4 was the potential predictor of retear regardless of sex (Odds ratio=5.25 (1.38, 20.02); p = 0.02). Conclusion: There is no definite association of rotator cuff retear and radiographic parameters including CSA, GI, LAA, and AI in this study.