Objective assessment of corticosteroid effect in plantar fasciitis: Additional utility of ultrasound

Background: although plantar fascia thickening is well documented as a sonographic criterion for the diagnosis of plantar fasciitis (PF), however it was less evaluated as an objective measure of response to treatment. It is unknown to what extent if any different responses to different treatments are related to the ultrasound (US) morphology changes. We aimed to evaluate changes in US findings in correlation to pain reported. Methods: this prospective observational trial included 21 plantar fasciitis patients (26 feet), resistant to conservative treatment for at least 2 months. Plantar fascia thickness and echogenicity were evaluated, compared to asymptomatic feet and correlated with visual analogue scale (VAS) and Heel Tenderness Index (HTI), before and after dexamethasone (DXM) iontophoresis in group I, and DXM injection in group II. Results: increased thickness and reduced echo - genicity were constant in symptomatic feet, with high statistical significant difference compared to asymptomatic side. Correlation between plantar fascia thickness with VAS and HTI before and after treatment showed statistically significant positive correlation (p<0.05). ROC curve test showed that reduction of plantar fascia thickness by US in response to DXM had 100% sensitivity, 65.2% specificity and 69% accuracy, with higher specificity and accuracy than VAS. Conclusion: US changes showed concurrent validity correlated with self-reported clinical improvement. Accordingly, ultrasound can be considered an objective useful tool for monitoring response to corticosteroid in patients with plantar fasciitis.