Efficacy of Adjunctive Photobiomodulation in Patellofemoral Pain Syndrome: A Systematic Review and Meta-Analysis.
Hongxiu Chen, Somkiat Asawaphureekorn, Nuttaset Manimmanakorn and 2 others
PMID 42326590WHAT IT FOUND
Adding laser or infrared light therapy to exercise for kneecap pain did not significantly reduce pain when four small trials were pooled.
Two trials alone reported benefit, but they used different devices and doses, and the studies disagreed with each other.
Key findings
01Pooled across four trials, the effect on pain favoured light therapy but did not reach statistical significance (effect size −1.520; 95% confidence interval −3.542 to 0.502; P = .097).
02The four trials disagreed markedly with one another about how much light therapy helped, with very high heterogeneity (I² = 91.1%); on their own, two of the four reported significant pain relief in favour of light therapy.
03In the largest included trial, 46 adolescents who had 12 weeks of physiotherapy plus infrared therapy had lower pain scores than those given physiotherapy alone (2 versus 4 on the visual analogue scale) and better balance and knee function scores.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only four trials and 162 participants in total, so the pooled analysis is underpowered and the authors could not run subgroup or sensitivity analyses. The trials were pooled even though they delivered what the authors themselves call clinically distinct interventions (classic photobiomodulation, laser acupuncture and monochromatic infrared energy) with wavelengths from 590 to 905 nm and 4 to 36 sessions; the authors say this drove the very high heterogeneity. Everyone studied was aged 15 to 25 and most were women, so nothing here tells you about older adults or a more mixed caseload with patellofemoral pain. There was no long-term follow-up, so the review says nothing about whether any pain relief lasts. One of the four trials, the 46-adolescent infrared trial, was rated high risk of bias overall because participants and staff were not blinded.
Declared interests
The paper's disclosure statement is a single word, 'None'. No funding source is reported anywhere in the article.
The easy way to misread this
Do not read this as evidence that laser or light therapy works for kneecap pain. The pooled result for pain did not reach statistical significance (P = .097), the trials were so different from one another that pooling them is questionable, and the favourable direction of the pooled estimate rests on two individual trials, one of which was rated high risk of bias because participants and staff were not blinded.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →