Sonography in diagnosis of adhesive capsulitis of the shoulder: a case-control study

Abstract

Purpose: Adhesive capsulitis (AC) of the shoulder has been a diagnosis of exclusion on sonography due to lack of specific diagnostic criteria. This study prospectively assesses the efficacy of sonography using multiple static and dynamic parameters for diagnosis of AC.

Materials and methods: Shoulder sonography was performed independently by two musculoskeletal radiologists on 90 subjects (60 symptomatic and 30 controls). All symptomatic subjects were subjected to an MRI. Based on clinical and MRI diagnosis, three groups were made: AC (n = 30), painful shoulders (PS) (n = 30), and control group (CL) (n = 30). The sonographic parameters studied were: coracohumeral ligament (CHL) thickness, increased soft tissue in rotator interval (static parameters) and restriction of abduction and external rotation on dynamic scanning. These were compared within the three groups and the accuracy of each parameter in isolation and in combination for diagnosis of AC was calculated.

Results: Sonographic visualisation of CHL (96.7%) and its mean thickness (1.2 mm) were highest in the AC group (p < 0.01). A cut-off value of 0.7 mm was found to be accurate (sensitivity 93.1%, specificity 94.4%) for diagnosing AC. Increased soft tissue in the rotator interval was seen in the AC group and had a high sensitivity of 86.2% and specificity of 92.8%. On dynamic scanning, restriction of external rotation was specific (sensitivity 86.2%, specificity 92.8%), whereas restriction in abduction was non-specific (specificity 6.7%). Inter-observer agreement was substantial for CHL visualisation (kappa 0.66). Overall, sonography, using multiple parameters, revealed a high sensitivity and specificity (100 and 87%, respectively) for diagnosis of AC of the shoulder.

Conclusion: Sonography revealed a high accuracy for diagnosing AC of the shoulder and in differentiating it from other causes of painful shoulder. It, thus, has the potential to be adopted as a preferred imaging modality.

Keywords: Adhesive capsulitis; CHL; Coracohumeral ligament; Frozen shoulder; Rotator interval; Shoulder sonography.

Conflict of interest statement

Conflict of interest

All author declare that they have no conflict of interest.

Ethical standard

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Written informed consent was obtained from patients for publication of this report and images.

Funding

None.

Figures

Fig. 1

Sonogram (oblique axial view) showing a normal thin CHL (0.4 mm) in control patient, b thickened CHL (1.2 mm) in adhesive capsulitis patient

Fig. 2

a Sonographic image of normal rotator interval, containing long head of biceps, CHL (single asterisk) and superior glenohumeral ligament (number sign). b, c Patient with adhesive capsulitis showing increased soft tissue and vascularity within the rotator interval

Fig. 3

Sonogram a, b reveal normal abduction showing complete passage of tendon and subacromial-subdeltoid bursa beneath the acromion in a control subject. Sonogram c, d in adhesive capsulitis showing incomplete passage of supraspinatus (SS) tendon beneath the acromion (A). T greater tuberosity

Fig. 4

Illustration showing probe position for dynamic assessment of external rotation

Fig. 5

Sonograms depicting a, b normal external rotation (right shoulder); subscapularis pointing to 11 o’clock position at the start of external rotation moves to 7 o’clock position at the end of maximum external rotation. c, d Restriction of external rotation in adhesive capsulitis; subscapularis points to 11 o’clock position at the start and is restricted before 9 o’clock position at end of movement

Fig. 6

a Fat suppressed Proton Density Fast Spin Echo oblique coronal image shows thickened (7.4 mm) joint capsule and synovium (opposed arrows) in a subject with adhesive capsulitis, b control subject for comparison

Fig. 7

a Sagittal MR image in a subject with adhesive capsulitis shows poorly defined soft tissue intensity encasing the CHL (arrow). b Normal rotator interval for comparison. Note the thin dark band of the CHL (white arrow) coming to sit above the biceps tendon (white dot), beneath the supraspinatus (ss). Subscapularis (sub) is shown

Fig. 8

Pre (a) and post (b) gadolinium sagittal oblique image shows moderate enhancement of scar tissue in the rotator interval (opposed arrows) in adhesive capsulitis

Fig. 9

a A box plot of the CHL thickness in the three groups (the median is the horizontal line in the rectangles) reveals highest thickness in AC group. b ROC curve for CHL thickness