Mediators and moderators of scapular focused interventions on shoulder disability in individuals with chronic shoulder pain: Secondary analysis of a randomized controlled trial.

Objective: To explore potential mediators of treatment effect and moderators of scapular-focused interventions on shoulder disability at 12-week follow-up in patients with chronic shoulder pain.

Design: Secondary analysis of a randomized controlled trial that compared the effects of scapular movement training with standardized exercises.

Methods: Sixty-four participants with chronic shoulder pain were enrolled in the trial, of whom 58 completed the 12-week follow-up and were included in these analyses. Shoulder disability was assessed with Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Potential mediators were scapular upward rotation, kinesiophobia, and fear avoidance beliefs. Potential moderators were kinesiophobia, fear avoidance beliefs, and duration of symptoms.

Results: Kinesiophobia, fear avoidance, and scapular upward rotation did not (p >0 .05) mediate the effects of scapular focused interventions on shoulder disability. Our sensitivity analyses indicated that the findings are likely to change because there were some small residual confounding factors between those mediators and the shoulder disability scores at 12 weeks. Kinesiophobia, fear avoidance, and duration of symptoms did not moderate the effects of the intervention on shoulder disability.

Conclusions: Kinesiophobia, fear avoidance, duration of symptoms, and scapular upward rotation did not mediate or moderate the effects of scapular-focused interventions on shoulder disability at 12-week follow-up.