Objective: The purpose of this study was to examine the association between clinical features and MRI findings in adhesive capsulitis of the shoulder.
Materials and methods: This study included 103 patients (41 men, 62 women) with adhesive capsulitis. The MRI findings were correlated with pain intensity, range of motion, and clinical stage. Joint capsule edema in the axillary recess, extracapsular edema, obliteration of the subcoracoid fat triangle, and effusion in the long head biceps tendon sheath were assessed by two radiologists using fat-suppressed T2-weighted images. Joint capsule thickness in the axillary recess and degree of external rotation during MRI were also measured. Intraclass correlation coefficient and kappa values were obtained. Associations between MRI findings and clinical features were assessed by statistical analyses.
Results: Anterior extracapsular edema was associated with range of motion on external rotation and abduction (p < 0.01). Joint capsule edema in the humeral portion of the axillary recess was associated with range of motion on external rotation (p = 0.01). Joint capsule thickness in the humeral portion of the axillary recess and height of the axillary recess were associated with pain intensity (p < 0.05). Joint capsule edema in the humeral portion of the axillary recess and obliteration of the subcoracoid fat triangle were significantly more common in the early stages of adhesive capsulitis (p < 0.05). Joint capsule thickness in the humeral portion of the axillary recess at stage 1 (4.67 ± 1.73 mm) was significantly different from the thickness at the later stages (stage 2, 3.73 ± 1.49 mm; stages 3 and 4, 3.67 ± 1.44 mm) (p < 0.05).
Conclusion: MRI is useful for assessing clinical impairment and predicting the clinical stage of adhesive capsulitis.
Keywords: MRI; adhesive capsulitis; frozen shoulder; shoulder.