Objective: The purpose of this article is to correlate MRI arthrographic findings with range of shoulder motions in patients with frozen shoulder.
Materials and methods: Shoulder MRI studies of 40 patients (22 women and 18 men; mean age, 52.8 years) with frozen shoulder were retrospectively compared with MRI studies of 40 age- and sex-matched control subjects without frozen shoulder. The thickness of the coracohumeral ligament and the capsule in axillary recess were measured retrospectively. The range of shoulder motions, including external rotation (ER), internal rotation (IR), lateral abduction, and forward flexion (FF), were prospectively evaluated by one experienced orthopedic surgeon.
Results: The mean (±SD) thickness of the coracohumeral ligament (4.13±1.04 vs 2.51±0.59 mm; p=0.000) and the capsule in axillary recess (3.97±1.45 vs 2.33±0.87 mm; p=0.000) were significantly greater in the patient group than in the control group. Multiple linear regression showed that only coracohumeral ligament thickness was significantly associated with ER (R2=0.418; p=0.000) and IR (R2=0.346; p=0.001), but not with lateral abduction and FF. Capsular thickness in axillary recess was not significantly correlated with any shoulder motion.
Conclusion: Coracohumeral ligament thickness on MR arthrography correlates with the range limitation of ER and IR in patients with frozen shoulder.