The Effects of Photobiomodulation on Knee Function, Pain, and Exercise Tolerance in Older Adults: A Meta-analysis of Randomized Controlled Trials

To assess whether photobiomodulation therapy (PBMT) enhances the benefits of exercise in older adults.PubMed, Scopus, Medline, and Web of Science, dated to February 2023.All included studies were randomized controlled trials of PBMT combined with exercise co-intervention in persons 60 years and older.Western Ontario and McMaster University Osteoarthritis Index (WOMAC-total, pain, stiffness and function), perceived pain intensity, timed Up and Go (TUG) Test, 6-min walk test (6MWT), muscle strength, and knee range of motion were included.Two researchers independently performed data extraction. Article data were extracted in Excel and summarized by a third researcher.The meta-analysis included 14 of the 1864 studies searched in the database. No statistical differences were found between the treatment and control groups in terms of WOMAC-stiffness (mean difference [MD]=-0.31, 95% confidence interval [CI] -0.64 to 0.03), TUG (MD=-0.17, 95% CI -0.71 to 0.38), 6MWT (MD=32.2, 95% CI -44.62 to 109.01), or muscle strength (standardized mean difference=0.24, 95% CI -0.02 to 0.50). However, statistically significant differences were found for WOMAC-total (MD=-6.83, 95% CI -12.3 to -1.37), WOMAC-pain (MD=-2.03, 95% CI -4.06 to -0.01), WOMAC-function (MD=-5.03, 95% CI -9.11 to -0.96), visual analog scale/numeric pain rating scale (MD=-1.24, 95% CI -2.43 to -0.06), and knee range of motion (MD=1.47, 95% CI 0.07 to 2.88).In older adults who exercise regularly, PBMT can potentially provide additional pain relief, improve knee joint function, and increase knee joint range of motion.