Impact of Imaging Height on Diagnostic Accuracy of the "Too Many Toes" Sign in Flatfoot

The "too many toes" sign is a clinical indicator for evaluating flatfoot. However, standardized assessment conditions remain undefined. In rehabilitation settings, this sign is used to monitor alignment, functional progression, and response to interventions such as intrinsic foot muscle training and gait retraining. Despite its widespread use, the height at which images are obtained may affect diagnostic interpretation. This study aimed to clarify the influence of imaging height on the assessment of the "too many toes" sign in patients with flatfoot.

In this cross-sectional observational study, 11 patients with flatfoot were evaluated preoperatively. Standing photographs were captured at floor level and at 40-cm height behind the participants. The horizontal distance between the lateral malleolus and the fifth toe was measured using ImageJ. Two board-certified foot-and-ankle surgeons assessed the presence of the "too many toes" sign. Statistical comparisons were performed using t-tests and a McNemar test.

The mean horizontal distance from the lateral malleolus to the fifth toe significantly increased from 0.47 ± 0.13 cm at floor level to 0.59 ± 0.15 cm at 40-cm height. From the floor-level images, two cases were classified as positive for the "too many toes" sign and nine as negative. Conversely, images obtained at 40-cm height identified ten positive and one negative case.

Imaging height significantly influences the visibility of the lateral toes and assessment of the "too many toes" sign in flatfoot, highlighting the need to standardize camera height for consistent clinical evaluations.