Range of shoulder motion in patients with adhesive capsulitis; Intra-tester reproducibility is acceptable for group comparisons

BACKGROUND: Measurements of range of motion play a key role in shoulder research. The purpose of this study is to investigate intra-observer reproducibility of measurements of active and passive range of motion in patients with adhesive capsulitis. METHODS: The study was carried out in a population consisting of 32 patients with clinical signs of adhesive capsulitis. A specified measurement protocol was used, and range of motion in affected and non-affected shoulders was measured twice for each patient with a one-week interval. RESULTS: For most of the investigated individual movements, test-retest differences in range of motion score of more than approximately 15° are not likely to occur as a result of measurement error only. Point-estimates for the intraclass correlation coefficient ranged from 0.61 to 0.93. CONCLUSION: Range of motion of patients with adhesive capsulitis can be measured with acceptable reproducibility in settings where groups are compared. Scores for individual patients should be interpreted with caution.