Functional improvement and scar impact of electromyography (EMG)-driven robotic training on nerve damage and hypertrophic scars in hands that underwent skin grafting after burns: a prospective, randomized, single-blinded study.

BACKGROUND

Burns deeper than deep-second degree cause hypertrophic scarring and nerve injuries, resulting in limited range of motion (ROM), decreased muscles strength, and impaired hand function. Thus, early rehabilitation is essential for optimal functional recovery. We aimed to investigate the effects of electromyography (EMG)-driven robotic training on hand function and scar characteristics in patients with burn-induced nerve damage and scarring.

MATERIALS AND

METHODS

Male participants with burn-induced hand dysfunction were enrolled in this randomized, single-blind controlled trial and randomly assigned to the experimental ([EG], n = 22) or control group ([CG], n = 23). The EG received EMG-driven robotic training combined with conventional therapy, while the CG received only conventional therapy, including hand stretching exercises, strength training, and functional training for 60 sessions over 12 weeks. Outcome measures included joint ROM, grip strength, Jebsen-Taylor hand function test (JTT), Purdue Pegboard test (PPT), ultrasound assessments of scar thickness, and scar characteristics, assessed before and after treatment.

RESULTS

After treatment, 19 and 20 patients were included in the EG and CG, respectively. No significant intergroup differences were observed except for total middle finger ROM ( P = 0.04). The EG showed significant improvements in ROM (middle and little fingers), grip and pinch strength (tip, key, and tripod pinch), JTT (feeding, light, heavy), PPT (affected hand), and skin characteristics (distensibility, elasticity) ( P < 0.05) after training. Scar thickness decreased in the EG, though not significantly ( P = 0.11) but remained unchanged in the CG ( P = 0.94). The CG showed significant improvements only in the JTT (small) ( P = 0.03) after training. The EG had significantly greater gains than the CG in grasp and tripod pinch strength, JTT (writing), PPT (affected hand), and skin distensibility ( P < 0.05).

CONCLUSION

EMG-driven robotic training combined with conventional treatment improved joint ROM, muscle strength, and scar distensibility in patients with reduced hand function after skin grafting, offering a potential new treatment modality for burnt hands.