Comparison of the effect of hyaluronic acid injection versus extracorporeal shockwave therapy on chronic plantar fasciitis: Protocol for a randomized controlled trial

Background: Plantar fasciitis is the most common cause of pain in the plantar region of the heel, and extracorporeal shockwave therapy (ESWT) is an option used in cases where conservative treatment fails. Hyaluronic acid (HA), initially used for osteoarthrosis, is a treatment option because it has been applied to extra-articular regions, such as tendons, ligaments, and fascia. The aim of the present study will be to evaluate the outcomes of pain, function, and personal satisfaction after a single injection of HA and to compare the results with those of ESWT in patients with chronic plantar fasciitis. Methods: The study will include 80 patients who will be randomized to receive three sessions of ESWT (n = 40) or a single ultrasound-guided HA injection in the plantar fascia (n = 40). The outcomes will include the visual analog pain scale score, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Foot and Ankle Outcome Score (FAOS). All of the assessments will be performed at baseline and 3, 6, and 12 months after treatment. Statistical analysis will be performed using the repeated measures ANOVA (analysis of variance test) for primary and secondary outcomes and also Fisher’s Least Significant Difference, a Post-Hoc test. We will use R software for statistical analysis, randomization, and sample size calculation. Results: Recruitment and data collection will begin in November 2020, with completion scheduled for November 2022 and final publication available in March 2023. Conclusion: This trial will evaluate the effects of a single ultrasound-guided HA injection for the treatment of chronic plantar fasciitis. Trial registration: Brazilian Clinical Trials Registry (Register Number: RBR-97vkx4) http://www.ensaiosclinicos.gov.br/rg/RBR-97vkx4/.