Validation of normalized truncated navicular height as a clinical assessment measure of static foot posture to determine flatfoot in children and adolescents: A cross sectional study.

Background: Reliability of clinical measures of static foot posture has been widely debated. However, validity of these measures has not been fully established especially in a pediatric population. The purpose of the study was to investigate reliability and validity of normalized truncated navicular height (NTNH) in assessment of static foot posture to determine flatfoot in children and adolescents using radiographic measures as a criterion gold standard measure.

Methods: A sample of 612 participants aged 6-18 years (12.3±3.3) were enrolled in the study. Clinical assessment of static foot posture using NTNH was compared to the gold standard radiographic measures. Reliability, validity and diagnostic accuracy were investigated. The optimal cutoff point for flatfoot using NTNH was calculated.

Results: NTNH demonstrated sensitivity of 98.4%, high positive predictive (PV +) value of 89.2%. The positive likelihood ratio was 19 and the negative likelihood ratio was 0.02. The area under the receiver operating curve (AUC) was 0.96 indicating high validity and diagnostic accuracy of NTNH. The optimal cutoff point for diagnosing flatfoot was NTNH≤0.195.

Conclusion: NTNH is a valid and diagnostically accurate clinical measure of static foot posture in children and adolescents.