High frequency of subscapularis tears in rotator cuff repairs: a cross-sectional analysis of 302 cases

Background: Subscapularis tendon tears are frequently underdiagnosed in rotator cuff (RC) pathology. While prior estimates suggest around a 30% prevalence, newer data indicate this may be underestimated. This retrospective study evaluated the frequency and characteristics of subscapularis tears in patients undergoing arthroscopic repair for posterosuperior (PS) RC tears. Methods: A cross-sectional analysis was conducted on 302 patients who underwent arthroscopic repair for PS tendon tears (supraspinatus and/or infraspinatus) between March 2021 and April 2024. Subscapularis involvement was classified intraoperatively using the Lafosse system. Preoperative magnetic resonance imaging (MRI) accuracy was compared with surgical findings. Results: Intraoperative findings revealed subscapularis involvement in 61.9% of cases, significantly higher than traditionally reported (P = .004). Lafosse type II was the most common category (50.8%). Preoperative MRI missed 49.2% of subscapularis tears confirmed during surgery, with a positive predictive value of 100.0% and a negative predictive value of 55.6%. Conclusion: Subscapularis tears were present in nearly two-thirds of patients with PS RC pathology, suggesting the true prevalence is substantially underrecognized. These results underscore the diagnostic limitations of MRI and support the need for systematic intraoperative evaluation to ensure accurate identification and management of subscapularis involvement.