Effect of low-level laser therapy plus exercise therapy on pain, range of motion, muscle strength, and function in knee osteoarthritis - a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 36576096 · doi:10.1080/08990220.2022.2157387
What was done
Researchers systematically searched six databases through December 2021 for English-language randomized controlled trials comparing low-level laser therapy (LLLT) plus exercise therapy (ET) against placebo LLLT plus ET in adults with knee osteoarthritis. Three reviewers independently extracted data and appraised study quality. Outcomes included pain, range of motion (ROM), muscle strength, and knee function assessed immediately post-treatment and at follow-up (4 to 32 weeks), pooled using random-effects standardized mean differences (SMD).
What was found
Across 14 RCTs encompassing 820 patients, LLLT plus ET significantly reduced pain compared to placebo LLLT plus ET immediately after intervention (SMD -0.58, p = 0.001) and at follow-up (SMD -1.35, p = 0.05). However, there were no statistically significant differences between groups for knee ROM, muscle strength, or overall knee function either immediately after treatment or during follow-up.
Why it matters
This review shows that while adding LLLT (typically 4–8 J, 640–905 nm per point over 10–16 sessions) to an exercise regimen provides supplementary pain relief in knee osteoarthritis, it does not translate into better joint mobility, strength, or functional recovery compared to exercise alone.
Limits
The analysis was limited to English-language publications, and the total sample size across 14 trials was relatively modest (820 patients). The abstract does not report confidence intervals, heterogeneity statistics (I²), or risk of bias assessments for the included trials. The borderline statistical significance for follow-up pain relief (p = 0.05) warrants cautious interpretation.