Validity of a Simple Footprint Assessment Board for Diagnosing the Severity of Flatfoot: A Prospective Cohort Study

Background: A simple, non-quantitative, and cost-effective diagnostic tool would enable the diagnosis of flatfoot without need for specialized training. A simple footprint assessment board that investigates which toe the cord passes through from the centre point of the heel to the most lateral point of the medial contour of the footprint has been developed to assess flatfoot. The purpose of this study was to verify the validity of a simple footprint assessment board for flatfoot. Methods: : Thirty-five consecutive patients with foot pain, foot injury, or any associated symptoms who underwent computed tomography (CT) were analysed prospectively. At the time of the CT scan, a footprint analysis using a simple footprint assessment board was performed. The results for the arch height evaluated by CT using the navicular index was compared to those evaluated with the simple footprint assessment board by regression analysis. Results: : The navicular index generally decreased as the score of the simple footprint assessment board increased. As the scores of the simple footprint assessment board decreased by approaching the great toe, the navicular index was higher, which is indicative of a higher likelihood of flatfoot. The scores derived from the simple footprint assessment board was correlated with the navicular index measured by CT, not only when the result of simple footprint assessment board was set as a non-continuous variable but also when the result was set as a continuous variable. Conclusions: : The findings of this study suggest that a simple footprint assessment board can be potentially useful to detect flatfoot. Trial Registration: retrospectively registered.