Association of Subscapularis Tear Severity With Posterosuperior Cuff Tear Morphology in a Combined‐Tear Surgical Cohort: A Retrospective Cross‐Sectional Study

Objectives In combined tears, the relationship between posterosuperior cuff tear (PSCT) morphology and subscapularis (SSC) tear severity is unknown. This study aimed to determine whether PSCT morphology is associated with SSC tear severity, which morphologies are associated with complete SSC rupture, and whether any association is confined to a particular severity threshold and persists after accounting for classification uncertainty and overall cuff extent. Methods A retrospective review of 368 patients who underwent arthroscopic surgery for combined, chronic, full‐thickness PSCTs with concomitant SSC tears between 2016 and 2023 was conducted. High‐resolution preoperative MRI and high‐definition intraoperative video recordings were used to classify PSCT morphology (crescent, U‐shaped, anterior L‐shaped, posterior L‐shaped, massive‐retracted) and SSC tears (Lafosse Types I–V). Interobserver agreement was almost perfect for both classifications. Binary logistic regression (adjusted for age, sex, side, and BMI) was used to evaluate associations with complete subscapularis rupture (Lafosse IV/V). Results The mean patient age was 60.3 ± 9.2 years. PSCT morphology was significantly associated with SSC tear severity (Monte Carlo P less than 0.001; Cramer's V 0.234). The proportion with complete SSC rupture rose from 23.8% in posterior L‐shaped and 25.6% in crescent tears to 39.6% in U‐shaped, 60.9% in anterior L‐shaped, and 71.4% in massive‐retracted tears. Complete subscapularis rupture was significantly more likely in anterior L‐shaped (adjusted OR 4.50, 95% CI 1.86 to 11.41) and massive‐retracted morphologies (adjusted OR 7.12, 95% CI 2.24 to 27.17), both surviving correction (adjusted p = 0.003). Posterior L‐shaped and U‐shaped morphologies showed no significant difference from crescent tears. Conclusion In surgically treated combined tears, PSCT morphology shows a graded association with SSC tear severity that is concentrated in the anterior L‐shaped and massive‐retracted morphology patterns. However, because most complete ruptures overall occurred within crescent tears due to their high prevalence, morphology alone cannot serve as a definitive diagnostic rule‐out tool. Nevertheless, anterior L‐shaped or massive‐retracted PSCT patterns warrant systematic inspection of the SSC.