Significance of the Aponeurotic Expansion of the Supraspinatus Tendon in Rotator Cuff Ruptures: An MR Arthrographic Study

Background and Objectives: This study aimed to assess the association between the aponeurotic expansion of the supraspinatus tendon (AEST) and supraspinatus tendon tears utilizing magnetic resonance (MR) arthrography in an extensive patient cohort and to determine its clinical relevance. Materials and Methods: All MR arthrography images were retrospectively assessed by two radiologists with expertise in arthrography. In both the AEST group and the comparison group consisting entirely of patients with rotator cuff tendon tears, the location and extent of the tear were documented, along with the distance between the tear and the AEST in the study group. In patients with AEST, it was also noted whether the tear extended to or structurally involved the AEST. Results: AEST was identified in 61 (7.4%) of the 827 MR arthrograms. The isolated supraspinatus tendon tear emerged as the most prevalent, representing 33.3% of patients with AEST. The triple combination of tears involving the supraspinatus, subscapularis, and infraspinatus accounted for 25.9% of patients with AEST. AEST tears alone were observed in just 3.3% of cases. The incidence of triple combination tears in patients with AEST was found to be significantly lower at 25.9% compared to 59.3% in the control group without AEST (p = 0.028). Conclusions: In this study, the authors found that the incidence of combined tendon tears in patients with AEST was significantly lower compared to the control group. This result suggests that the AEST likely acts as a structural barrier limiting the anterior progression of rotator cuff tears, particularly toward the subscapularis tendon.