Objective
To define arthrographic findings in patients with frozen shoulder and to evaluate the therapeutic effect of arthrographic capsular distension and rupture.

Method
Thirty patients who were clinically diagnosed as frozen shoulder were enrolled. During a trial of intra-articular injection of 35 mL of fluid which contained 8 mL of 1% lidocaine, 2 mL of prednisolone (80 mg) and 25 mL of radiocontrast material, arthrographic findings and the occurrence of iatrogenic capsular tear were observed. Passive range of shoulder motion (percent of normal, %) at flexion, abduction, internal rotation, and external rotation was measured at pre- and 1 week post-injection. The therapeutic effect of the procedure was statistically analyzed by paired Student's t-test.

Results
Mean age of the subjects was 57-years-old (range: 40∼76 years) and mean duration of the symptom was 6 months (2∼42 months). A decreased joint volume of less than 10 mL (100%), poor or absent filling of the axillary recess or subscapular bursa (75.9%), nonfill of the biceps tendon sheath (37.9%), and irregularity of capsular insertion (31.0%) were typical abnormal arthrographic findings. In one week after arthrographic distension and rupture, the passive range of shoulder motion was significantly (p＜0.05) increased at flexion, abduction and external rotation, of which the range of external rotation was the most remarkably increased (mean, 23.9%).

Conclusion
Distension arthrography was useful for increasing shoulder motion in frozen shoulder, especially at flexion, abduction and external rotation.