Efficacy of laser acupuncture for patients with knee osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis investigated the efficacy of laser acupuncture in the treatment of knee osteoarthritis, analyzing 13 randomized controlled trials with 611 participants. Knee osteoarthritis is a highly prevalent chronic condition that causes pain, functional limitation, and reduced quality of life, affecting millions of people worldwide. With population aging and the limitations of traditional pharmacological treatments, noninvasive therapies such as laser acupuncture have attracted increasing interest. Laser acupuncture combines the principles of traditional acupuncture with photobiomodulation, offering a needle-free approach that stimulates specific points with low-intensity laser light.

The studies included in the analysis covered diverse treatment protocols, ranging from 2 to 13 weeks in duration, with frequencies of 1 to 5 sessions per week. Laser parameters showed considerable variability across studies, including wavelengths of 650 to 904 nm and different power outputs and dosing protocols. The most frequently used acupoints were GB-34, ST-36, ST-34, and SP-9, following traditional Chinese medicine principles for the treatment of joint pain. Primary outcomes focused on pain assessment through validated scales such as the WOMAC, the visual analog scale (VAS), and the numeric pain rating scale.

Secondary outcomes included joint function and range of motion. Data analysis revealed that laser acupuncture did not demonstrate statistically significant benefits compared with control groups for any of the outcomes assessed. For WOMAC pain, the pooled effect showed a standardized mean difference of 0.04 (95% CI −0.36 to 0.45), indicating no clinically relevant difference. Similar results were observed for pain measured by VAS and other scales.

Joint function showed a non-significant trend toward improvement (SMD −0.32; 95% CI −0.94 to 0.30), suggesting a possible functional benefit that did not reach statistical significance. An important limitation of this review was the substantial heterogeneity observed across studies (I² > 70%), attributed mainly to differences in laser parameters, treatment protocols, and acupoint selection. This methodological variability makes definitive conclusions about the efficacy of the intervention difficult. Some individual studies reported significant benefits, but these did not hold up in the pooled analysis, possibly due to differences in experimental design and study populations.

Risk of bias assessment showed that seven studies had low risk, five had some concerns, and one had high risk, mainly related to blinding of participants and researchers. Although laser acupuncture is considered safe and noninvasive, current evidence does not support its recommendation as a first-line treatment for knee osteoarthritis. However, it may be considered as adjunctive therapy for patients seeking non-pharmacological alternatives, especially those with contraindications to medications or a preference for integrative approaches. The clinical implications include the need to standardize laser acupuncture protocols, with clear definition of parameters such as wavelength, power, energy density, and treatment duration.

Future studies should focus on larger-scale, multicenter trials with standardized protocols and extended follow-up to establish long-term efficacy and identify patient subgroups that may benefit most from this intervention.