The effect of photobiomodulation therapy on fracture healing: a systematic review and meta-analysis of animal studies.

This systematic review and meta-analysis aimed to evaluate the impact of photobiomodulation therapy (PBMT) on fracture healing in animal models. Following PRISMA guidelines, an electronic search was conducted in PubMed/MEDLINE, Scopus, Embase, and Web of Science databases without date or language restrictions. Animal studies evaluating the effect of PBMT on the healing of complete fractures were included. SYRCLE's risk of bias assessment tool was used for quality appraisal. Meta-analysis and sensitivity analysis were performed for selected outcome measures using Stata version 16, with a significance level of 0.05. Of 1,656 studies, 27 met eligibility criteria. Rabbits and rats were used in 17 and 10 studies, respectively. The tibia was the most common site of fracture, followed by the femur, mandible, and radius. The most frequently used emitters were 780 nm LASER, followed by 808 nm and 830 nm LASER. LEDs were used in comparison to LASERs in three studies and solely in one study. The most frequent energy density and power density were 4 J/cm2 and 100 mW/cm2, respectively. Radiography, histology, mechanical testing, and spectroscopy were the most common assessment methods of fracture healing. While most studies reported PBMT's positive effect on fracture healing, meta-analysis found no significant impact on maximum fracture force or Raman peaks of hydroxyapatite, indicating no significant influence on mineralization (P > 0.05). Although PBMT shows potential for enhancing fracture healing in animal models, meta-analysis showed that it has no effect on maximum force of fracture or Raman peaks of hydroxyapatite. Registration: The protocol of this systematic review was registered on PROSPERO with the ID CRD42024514398.