Effects of laser acupuncture on pain and motor function in musculoskeletal disorders: A systematic review and meta-analysis

This systematic review and meta-analysis examined the effects of laser acupuncture (LA) on pain and motor function in musculoskeletal disorders, analyzing data from 19 studies with 1,816 participants. Laser acupuncture uses low-intensity laser light to stimulate acupoints, minimizing discomfort and the risk of infection. The study was conducted following PRISMA guidelines and registered with PROSPERO. The search covered 10 English- and Chinese-language databases, including studies from inception through June 2025.

Inclusion criteria were randomized controlled trials in adults with musculoskeletal disorders, comparing LA with placebo, usual care, or other forms of acupuncture. The majority of studies (73.68%) focused on knee osteoarthritis, with others including shoulder periarthritis, subacromial impingement syndrome, temporomandibular disorders, and myofascial pain syndrome. Laser protocols varied considerably in type (diode, CO₂, combined), wavelength (650–10,600 nm), energy density, and treatment duration. ST-35 was the most frequently used point, followed by SP-9 and SP-10.

The meta-analysis revealed significant effects of LA across all primary outcomes. For pain, the effect size was moderate (g = 0.59, 95% CI: 0.42–0.76), representing clinically meaningful improvement. Physical function also improved moderately (g = 0.50, 95% CI: 0.28–0.73), as did joint stiffness (g = 0.55, 95% CI: 0.43–0.67). The greatest benefit was observed in range of motion (g = 0.76, 95% CI: 0.48–1.04), considered a substantial effect.

Walking speed showed a trend toward improvement (g = 0.38, 95% CI: −0.02–0.77), although it was not statistically significant. Subgroup analysis revealed that CO₂ lasers demonstrated superior efficacy for functional recovery, whereas diode lasers were more effective for reducing pain and stiffness. Meta-regression identified wavelength as a significant moderator, with longer wavelengths associated with greater pain relief and reduction in stiffness. Notably, meta-regression analysis found no significant association between pain improvement and gains in motor function, suggesting that the functional benefits of LA are independent of analgesia.

This indicates that LA may directly improve function through mechanisms such as tissue repair, modulation of local circulation, and neuromuscular effects, in addition to its analgesic effects. Most adverse events were mild and transient, including localized redness, tingling, and skin sensitivity. Moderate events, primarily blisters and transient increases in pain, were rare and mainly associated with CO₂ lasers. No serious adverse events were reported.

Risk of bias assessment showed that 47% of studies had 'some concerns,' mainly due to limitations in reporting allocation concealment and blinding. GRADE certainty of evidence was rated as 'low' for three outcomes and 'moderate' for two. The clinical implications are promising, especially for patients who cannot tolerate conventional exercise-based rehabilitation. LA offers a noninvasive alternative that simultaneously addresses pain and motor dysfunction.

The findings suggest that protocols should consider specific laser parameters, with longer wavelengths potentially offering superior benefits.