Low level laser therapy for osteoarthritis and rheumatoid arthritis: A metaanalysis

Objective. Osteoarthritis (OA) and rheumatoid arthritis (RA) affect a large proportion of the population. Low level laser therapy (LLLT) was introduce d as an alternative noninvasive treatment for RA and OA about 10 years ago, but its effectiveness is still controversial. We assessed the effectivenes s of LLLT in the treatment of RA and OA. Methods. A systematic review was conducted, following an a priori protocol, according to the methods recommended by the Cochrane Collaboration. Trials were identified by a literature search of Medline, Embase, and the Cochran e Controlled Trials Register. Only randomized controlled trials of LLLT for the treatment of patients with a clinical diagnosis of RA or OA were eligi ble. Thirteen trials were included, with 212 patients randomized to laser a nd 174 patients to placebo laser, and 68 patients received active laser on one hand and placebo on the opposite hand. Treatment duration ranged from 4 to 10 weeks. Followup was reported by only 2 trials for up to 3 months. Results. In patients with RA, relative to a separate control group, LLLT re duced pain by 70% relative to placebo and reduced morning stiffness by 27.5 min (95% CI -52.0 to -2.9), and increased tip to palm flexibility by 1.3 c m (95% CI -1.7 to -0.8). Other outcomes such as functional assessment, rang e of motion, and local swelling were not different between groups. There we re no significant differences between subgroups based on LLLT dosage, wavel ength, site of application, or treatment length. In RA, relative to a contr ol group using the opposite hand, there was no difference between control a nd treatment hand, but all hands were improved in terms of pain relief and disease activity. For OA, a total of 197 patients were randomized. Pain was assessed by 3 trials. The pooled estimate (random effects) showed no effec t on pain (standardized mean difference -0.2, 95% CI -1.0 to +0.6), but the re was statistically significant heterogeneity (p > 0.05). Other outcomes o f joint tenderness, joint mobility, and strength were not significant. Conclusion. LLLT should be considered for short term relief of pain and mor ning stiffness in RA, particularly since it has few side effects. For OA, t he results are conflicting in different studies and may depend on the metho d of application and other features of the LLLT Clinicians and researchers should consistently report the characteristics of the LLLT device and the a pplication techniques. New trials on LLLT should make use of standardized, validated outcomes. Despite some positive findings, this metaanalysis lacke d data on how effectiveness of LLLT is affected by 4 factors: wavelength, t reatment duration of LLLT, dosage, and site of application over nerves inst ead of joints. There is a need to investigate the effects of these factors on effectiveness of LLLT for RA and OA in randomized controlled clinical tr ials.