Magnetic resonance imaging-based quantitative analysis of intracapsular ligaments in patients with rotator cuff injuries

The aim of this study was to retrospectively examine the structural attributes of intracapsular ligaments among individuals presenting with rotator cuff injuries, utilizing MRI-based quantitative measures, and to investigate their relationship with the various forms of rotator cuff tears. Clinical records of 122 individuals with arthroscopically confirmed rotator cuff injuries were retrospectively gathered between January 2023 and September 2025. All patients underwent standardized shoulder MRI examinations. Radiologists independently evaluated the morphology, thickness, and signal of the superior, middle, and lower glenohumeral ligaments, along with the coracoacromial ligament, on the obtained images and examined their correlation with rotator cuff tear types (Partial-thickness tear group, PTRCT group; Full-thickness tear group, FTRCT group). MRI clearly visualized intracapsular ligament structures in all cases with good inter-observer agreement (Kappa >0.75). Ligament abnormalities were widespread in individuals diagnosed with rotator cuff tears, most frequently affecting the coracoacromial ligament (82.0%) and the superior glenohumeral ligament (78.7%). Correlation analysis indicated that abnormalities of the coracoacromial ligament and the SGHL were significantly associated with full-thickness tears. In contrast, damage to the anterior band of the inferior glenohumeral ligament (IGHL) showed a stronger association with partial-thickness tear and independently correlated with greater posterior displacement of the humeral head ( P < 0.001) and lower shoulder function scores (ASES) ( P = 0.01). Magnetic resonance imaging is capable of effectively detecting alterations in the intracapsular ligaments linked to rotator cuff pathology. The observed patterns of ligament involvement demonstrate distinct associations with the nature of the rotator cuff tears. Moreover, the structural condition of the IGHL-AB plays a particularly critical role in preserving shoulder stability and functional capacity. This research underscores the significance of integrating the evaluation of intracapsular ligaments into the standard imaging assessment for rotator cuff injuries.