Efficacy of High-Intensity and Low-Level Laser Therapy Combined With Exercise Therapy on Pain and Function in Knee Osteoarthritis: A Systematic Review and Network Meta-analysis

Introduction: High-intensity laser therapy (HILT) and low-level laser therapy (LLLT) combined with exercise therapy (ET) have emerged as effective treatment options for musculoskeletal pain. However, there have remained uncertainties regarding the magnitude of their effects in reducing pain and improving function in patients with knee osteoarthritis. Hence, we performed a systematic review and network meta-analysis of available evidence in the literature to answer this query. Methods: A literature search was carried out in Embase, PubMed, and Scopus databases without any language restrictions from 1 January 1990 to 31 December 2023. We examined randomized controlled trial (RCT) studies that investigated the efficiency of HILT or LLLT plus knee osteoarthritis ET in pain and functional improvement of the knee. We performed a network meta-analysis and provided the standardized mean difference (SMD) with a 95% confidence interval (CI) by pooling the continuous data on the visual analogue scale (VAS) pain score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score using a random-effects model. Results: In total, 11 eligible RCTs were included. Our analysis revealed significant improvements in the VAS pain and WOMAC function scores on weeks 4 and 8 after interventions in groups treated with LLLT + ET and HILT + ET compared with placebo + ET. Moreover, HILT + ET showed a greater reduction in the VAS pain score (SMD = -1.41; 95% CI: -2.05 to -0.76) and improvement in the WOMAC function score (SMD = -2.20; 95% CI: -3.21 to -1.19) than LLLT + ET in week 8. Conclusion: Based on our findings, both HILT + ET and LLLT + ET treatments effectively reduced pain and improved function, but HILT + ET showed a more significant improvement in both outcomes compared to LLLT + ET.