Wang W. et al. - Photobiomodulation, Pain, and Functional Recovery After Fracture: A Systematic Review and Meta-Analysis

In this meta-analysis, photobiomodulation was associated with a reduction in pain of approximately 0.74 points one week after a fracture, compared with a placebo. However, the authors reported no significant benefit between 4 and 26 weeks, nor in terms of bone healing.

What this study measured

Pain associated with a fracture affects the patient’s comfort and delays the start of rehabilitation. Weifeng Wang’s team sought to determine whether photobiomodulation—also known as low-intensity laser therapy—could reduce this pain and promote rehabilitation.

The protocol was registered on PROSPERO under number CRD42024591373. The authors searched PubMed, EMBASE, the Cochrane Library, and Web of Science through August 2025, including only randomized controlled trials. Twelve studies were included in the systematic review, and nine of them were included in the meta-analysis. The primary outcome was pain score; the secondary outcomes were function and bone healing.

Key Findings

The clearest evidence pertains to early pain. At one week, the pain score was lower in the photobiomodulation group than in the placebo group, with no heterogeneity among the studies. A second finding concerns grip strength in patients with upper-limb fractures.

• Pain at one week: mean difference of -0.74 points (95% CI -1.00 to -0.47; I² = 0%)
• Grip strength at 4 weeks: mean difference of 5.03 in favor of photobiomodulation (95% CI 4.29 to 5.78; I² = 0%)
• Pain and functional scores between 4 and 26 weeks: no significant difference
• Bone strengthening: no difference between photobiomodulation and placebo
• Adverse effects: None reported in the included studies

Subgroup analyses show that the difference in pain remains significant regardless of the fracture site and regardless of whether or not irradiation is applied to acupuncture points. It also remains significant for the various combinations of wavelengths studied.

How Photobiomodulation Affects Pain

The proposed mechanism remains hypothetical. Red and near-infrared light is thought to be absorbed by cytochrome c oxidase, an enzyme in the mitochondrial respiratory chain, which would promote ATP production. Locally, photobiomodulation may attenuate the inflammatory response and limit edema around the lesion—two factors that perpetuate pain following trauma. An effect on the conduction of nociceptive fibers and on pain-inducing mediators has also been proposed. These mechanisms were not directly tested in the included trials.

Limits You Should Know

Only nine studies could be pooled, all with limited sample sizes. Parameters vary from one trial to another, particularly wavelengths and treatment regimens, which makes it difficult to make any precise recommendations. The effect on pain, approximately 0.74 points, is consistent but modest relative to the scales used in clinical practice. Most importantly, the authors highlight the lack of demonstrated benefit beyond 4 weeks and the lack of effect on bone healing. Data on functional recovery of the mandible remain inconsistent, and no GRADE rating is reported in the abstract.

What This Means in Practice

The clinical impact remains limited: it may provide some relief from pain during the very first few days, which could potentially facilitate earlier mobilization. Photobiomodulation is not presented as an alternative to fracture management, but as a complementary treatment with short-term benefits. The abstract does not specify a single wavelength, power level, or number of sessions: the authors call for future studies to standardize these parameters. No adverse effects were reported.

Frequently Asked Questions

Does photobiomodulation really relieve pain after a fracture?

In this meta-analysis, yes, but only to a limited extent and over a short period of time. Pain scores measured at one week were, on average, 0.74 points lower than those for the placebo. Beyond 4 weeks, no significant difference was found.

Does photobiomodulation accelerate bone healing?

The data compiled here do not show this. The authors found no difference in bone consolidation between the treatment group and the placebo group. They recommend further studies to specifically evaluate this issue.

How many sessions are needed?

The study abstract does not provide a quantified protocol. The designs varied from one trial to another, and the authors consider that defining standardized parameters remains a research goal.

Reference

Wang W, Xiu R, Zhao X, et al. Effect of photobiomodulation on pain relief and functional improvement in fractures: a systematic review and meta-analysis. Annals of Medicine, 2026. PMID 42080480. View the study on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.