Photobiomodulation with low-level laser therapy for treating Achilles tendinopathy: a systematic review and meta-analysis

Objective: The purpose of this study was to determine the benefits and harms of low-level laser therapy for Achilles tendinopathy. Data sources: Search strategies were conducted (from inception to February 2020) in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Literatura Latino Americana em Ciencias da Saude e do Caribe (LILACS), Physiotherapy Evidence Database (PEDro), SPORTDiscus, ClinicalTrials.gov, World Health Organization (WHO)-ICTRP and OpenGrey databases, to retrieve all randomized controlled trials that compared laser therapy with inactive/active interventions. Review methods: This study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The risk of bias was assessed using the Cochrane Risk of bias table. Meta-analyses were performed on dependence of homogeneity, otherwise results were reported narratively. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: Four trials (119 participants) were analyzed. Laser therapy associated to eccentric exercises when compared to eccentric exercises and sham had very low to low certainty of evidence in pain and function assessment. Despite one trial favored laser therapy at two months (mean difference (MD) -2.55, 95% confidence interval (95% CI) -3.87 to -1.23), the CIs did not include important differences between groups at 3 and 13 months. The function assessment showed an improvement favoring the placebo group at one month (MD 9.19, 95% CI -16.16 to -2.23) and non-significant difference between groups at 3 and 13 months. Adverse events were poorly reported but restricted to minor events related to the exercises. Conclusion: The certainty of evidence was low to very low, and the results are insufficient to support the routine use laser therapy for Achilles tendinopathy.