Ultrasound Imaging and Frozen Shoulder: Unlocking the Benefits, Navigating the Risks.

Frozen shoulder (FS), or adhesive capsulitis, remains a challenging clinical entity due to its insidious onset, variable presentation, and diagnostic overlap with other shoulder pathologies. While FS is traditionally diagnosed clinically, musculoskeletal ultrasound (MSKUS) is emerging as a valuable adjunct tool capable of identifying early-stage structural and vascular changes. This review synthesizes the current evidence on MSKUS's diagnostic utility, highlighting its capacity to visualize characteristic features such as capsular thickening, rotator interval (RI) hypervascularity, and effusion in the long head of the biceps tendon (LHBT) sheath-particularly prominent in early or intermediate disease stages. Although MSKUS is highly operator-dependent and demands substantial training, its integration into clinical assessment may enhance diagnostic precision, particularly when FS is suspected early. As the field advances, combining MSKUS findings with metabolic and inflammatory biomarkers may support a pathophysiological classification of FS, paving the way for more personalized, algorithm-based interventions. In summary, MSKUS provides a safe, accessible, and dynamic modality for detecting capsuloligamentous changes in FS. Its role in early diagnosis, differential screening, treatment monitoring, and future integration with systemic biomarkers supports its growing clinical relevance in both orthopedic and interdisciplinary settings.