ABSTRACT
BACKGROUND: Photobiomodulation therapy (PBMT) is widely used in the treatment of patients with musculoskeletal and sports disorders with a lack of significance in patients with sprain ankle. PURPOSE: This review investigated the effect of PBMT on pain, oedema, and function in patients with an ankle sprain. METHODS: A systematic search of the databases (MEDLINE, PubMed, EBSCO, Web of Science, Wiley Online Library, Science Direct, Physiotherapy Evidence (PEDro), and the Cochrane Databases) was performed from inception to the end of 2023 to identify any clinical study investigating the effect of PBMT on ankle sprain. PBMT parameters and measured outcomes were extracted. The primary measured outcome was pain and function, and oedema were secondary measured outcomes. Methodological quality was assessed using the PEDro scale. The level of evidence was determined by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. A random effect meta-analysis with forest plot was used to calculate standardized mean difference (SMD) at a 95% confidence interval and the overall effect size (ES). RESULTS: Six studies (598 patients) were included in the review and five studies in the meta-analysis. There were two fair-quality and four good-quality studies, with a moderate level of evidence on pain, and a low level of evidence on oedema and function. The meta-analysis revealed a significant overall effect of PBMT on pain with high ES [SMD - 0.88 (-1.76, -0.00), p = 0.05], with a non-significant effect on oedema and function with a medium ES [SMD - 0.70 (-1.64, 0.24), p = 0.14] on oedema and low ES on function [SMD - 0.22 (-0.69, 0.24), p = 0.35]. Significant heterogeneity was observed in all measured outcomes with high heterogeneity (I2 > 75%) in pain and oedema and moderate heterogeneity in function. CONCLUSION: PBMT is quite effective for patients with an ankle sprain. PBMT showed high effect size with a moderate level of evidence on pain intensity. The lack of significant effects of PBMT on function and edema with low level of evidence limit the confidence to the current results and recommend further large high-quality studies with higher PBMT intensity and fluency for standardisation of the irradiation parameters and treatment protocol. REGISTRATION: PROSPERO registration number (CRD42021292930).