Efficacy of Laser Therapy in the Treatment of Shoulder Impingement Syndrome: A Systematic Review and Meta-Analysis

Abstract Background Laser therapy is used as a noninvasive treatment for musculoskeletal diseases, including shoulder pain, but its efficacy in shoulder impingement syndrome remains controversial. This study aimed to systematically evaluate the efficacy and safety of laser therapy in shoulder impingement syndrome. Methods The PubMed, Embase, and Cochrane Library databases were searched from its establishment to June 2021. Randomized controlled trials (RCTs) in shoulder impingement syndrome were included. The primary outcome was pain, and the secondary outcomes were function and range of motion. Meta-analysis was performed with RevMan 5.3. Results A total of 12 RCTs and 669 participants were included. The results showed that laser therapy exhibited significant efficacy in shoulder impingement syndrome, especially in terms of pain release (MD=1.26, 95% CI=0.55–1.97, P=0.0005) and range of motion (MD=4.27, 95% CI=1.93–6.61, P=0.0003). However, the effect of shoulder function was uncertain (SMD=0.43, 95% CI=0–0.85, P=0.05). The subgroup analysis of pain showed that the efficacy of the laser therapy was related to the wavelength of the laser and the number of combined treatments. No adverse events were reported in the included trials. Conclusions Laser therapy can significantly relieve pain in shoulder impingement syndrome and has no adverse reactions.