Effect of shoulder internal rotation exercise with electromyographic and ultrasonographic biofeedback in patients with painful and restricted hand-behind-back motion: a randomized-controlled trial.

purposeTo investigate the additional effects of combining electromyography (EMG) and ultrasonography (US) biofeedback with internal rotation exercise in patients with painful and restricted hand-behind-back (HBB) movement, commonly limited by subcoracoid impingement and posterior shoulder tightness.

methodsForty-eight patients with shoulder periarthritis or subacromial pain syndrome or rotator cuff tear were randomly assigned to a control group (CG; internal rotation exercise only), an EMG biofeedback group (EMG-G), or a combined EMG and US biofeedback group (EMG + US-G). Exercises were performed daily for 4 weeks (10 repetitions × 3 sets) under weekly physical therapy supervision. The primary outcome measure was the C7-thumb distance. Secondary outcome measures included pain; Disability of the Arm, Shoulder, and Hand (DASH) score; internal rotation strength; and shoulder range of motion. Analyses were performed using an intention-to-treat approach with multiple imputation, applying mixed-effects models.

resultsA significant group-by-time interaction was observed for the C7-thumb distance (p = 0.007), with the EMG + US-G showing greater improvement compared with the CG. Pain decreased over time, with a significant group-by-time interaction (p = 0.049); however, no significant between-group differences were detected in post hoc analyses. No significant interactions were found for DASH score, internal rotation strength, or passive range of motion (p > 0.05).

conclusionThe addition of EMG and US biofeedback to internal rotation exercise was associated with improvement in HBB mobility in patients with limited HBB movement. The effects on pain were modest and should be interpreted cautiously, although a potential benefit cannot be excluded.