Correlation of Ultrasound Findings With Clinical Stages and Impairment in Adhesive Capsulitis of the Shoulder

Background: Ultrasound is an essential tool for diagnosing shoulder disorders. However, the role of ultrasound in assessing and diagnosing adhesive capsulitis has not been fully studied. Purpose: To evaluate the ultrasound features of adhesive capsulitis and estimate the correlations between clinical impairment and ultrasound parameters. Study Design: Case series; Level of evidence, 4. Methods: A total of 61 patients with clinically diagnosed unilateral adhesive capsulitis were retrospectively reviewed using high-resolution ultrasound. To compare ultrasound parameters, we performed ultrasound examinations on both affected and unaffected shoulders. Ultrasound parameters, including thickness of the coracohumeral ligament (CHL), rotator interval (RI), axillary recess (AR), hypervascularity of the RI, and effusion of the long head of the biceps tendon sheath, were measured. Passive range of motion (PROM), visual analog scale for pain, and the Shoulder Pain and Disability Index were used for clinical assessment. Results: The CHL, the RI, and the AR in affected shoulders were significantly thicker than in unaffected shoulders (P < .05). CHL thickness in affected shoulders was significantly correlated with PROM limitation, which included forward elevation, abduction, external rotation (ER), and internal rotation (IR) (P < .05). AR thickness correlated with passive forward elevation limitation and passive IR limitation (P < .05). The CHL was significantly thicker in stage 2 compared with stage 1, and the RI was thicker in stage 2 compared with stage 3. The diagnostic cutoff values for adhesive capsulitis were 2.2 mm for CHL thickness (77% sensitivity, 91.8% specificity) and 4 mm for AR thickness (68.9% sensitivity, 90.2% specificity). Conclusion: The ultrasound parameters associated with structural changes were correlated with clinical characteristics of adhesive capsulitis. Thickened CHL, RI, and AR were observed in affected shoulders. The cutoff values of 2.2 mm for CHL thickness and 4 mm for AR thickness can be used as cutoff diagnostic values for adhesive capsulitis.