OBJECTIVES: To investigate the ultrasonographic (US) changes and to determine the thickness of the joint capsule in rotator interval in shoulders with adhesive capsulitis.
METHODS: An oblique sagittal gray-scale and color Doppler US through the rotator interval were carried out in 87 shoulders in 77 individuals. The individuals included three study groups, group I: 17 shoulders in 17 patients (10 females, 7 males, mean age 53 years) having clinical and arthrographic evidences of adhesive capsulitis, group II: 50 shoulders in 50 patients (27 females, 23 males, mean age 56 years) who were referred for US because of shoulder pain with no clinical evidence of adhesive capsulitis, and group III: 20 shoulders in 10 asymtomatic volunteers (5 females, 5 males, mean age 35 years). We accessed the echogenecity and color Doppler signals of the rotator interval, and the thickness of joint capsule. Eight shoulders in group I received arthroscopic treatment in two months after US and available for comparison.
RESULTS: In group I, 9 shoulders (52.9%) demonstrated hypoechoic echotexture and increased vascularity within the rotator interval. Five shoulders had hypoechoic echotexture but no increase in vascularity, and 3 shoulders had a normal US appearance. Eight shoulders received arthroscopy disclosed fibrovascular inflammatory soft-tissue in the rotator interval which were consistent with adhesive capsulitis. All of them are hypechoic on US, and 4 of them show blood flow signals. The shoulders in group II and III showed no such abnormalities. The joint capsule at rotator interval was visualized in all the shoulders. The average thickness of the joint capsule was 2.3±0.4 mm in group I, 1.1±0.3 mm in group II and 1.5±0.6 mm in group III. The differences of group I to group II and group I to group III were statistically significant. But there was no significant difference between group II and III.
CONCLUSIONS: Ultrasonography provide an imaging tool for diagnosis of adhesive capsulitis. Presence of hypoechoic fibrovascular soft tissue and thickened joint capsule at rotator interval are suggestive of adhesive capsulitis.