Evaluation of the Differences in the MRI Findings Related to Primary and Secondary Adhesive Capsulitis

Purpose: The aim of this study is to describe the radiological findings of adhesive capsulitis due to different etiological factors and reveal that different clues due to different etiological causes should be considered in the diagnosis of adhesive capsulitis. Methods: The study group comprised 24 primary and 22 supraspinatus tendon rupture-related adhesive capsulitis patients with 24 individuals without adhesive capsulitis and with normal shoulder magnetic resonance imaging. Independent samples t-test and one-way analysis of variance tests were used to compare the measurements between the groups. Paired sample t-test and Cohen's kappa statistic were used to determine inter-observer reliability. The chi-squared test was used to determine the relationships between groups and categorical variables. Study participants were evaluated both qualitatively and quantitatively. Quantitative measurements included the thickness of the humeral and glenoid segment of the joint capsule and the thickness of the anterior joint capsule and the fluid depth within the biceps tendon sheath. The qualitative assessments included the detection of any signal abnormality at the rotator interval, the grading of the humeral and glenoid segment of the joint capsule, and the detection of any signal abnormality in respect of the anterior joint capsule. Results: A statistically significant difference was found between the groups of patients with primary adhesive capsulitis and with supraspinatus tear-related adhesive capsulitis in terms of the thickness of the humeral segment of the joint capsule at the axillary recess level (AUC = .729) (P: .006). Furthermore, setting the cutoff value for the thickness of the humeral segment of the capsule to 4.6 mm allowed the differentiation of primary adhesive capsulitis and supraspinatus tear-related adhesive capsulitis with a sensitivity of 70.8% and a specificity of 87.3%. Conclusion: In conclusion, the humeral segment of the joint capsule thickness at the axillary recess was found to be affected by different degrees depending on whether it is a primary or supraspinatus tear-related adhesive capsulitis.