Manual and Visual Assessment of Foot Type and Posture Correlate Poorly With Radiographic Assessment: A Cross-Sectional Study.

BACKGROUND

The purpose of this study was to assess how well manual and visual assessment of foot type agree with radiographic assessment. We hypothesized that quantitative measures would have better interrater reliability than qualitative measures, and that visual assessment of foot type would be strongly correlated with radiographic assessment.

METHODS

Bilateral foot photographs, radiographs, and physical examination were acquired on 92 participants to assess Radiographic Arch Type, calcaneal pitch, Meary angle, Arch Index, Photo Arch Type, Radiographic Foot Posture, Foot Posture Index, and Photo Foot Posture by 5 reviewers. Correlations between measures, interrater reliability, and sensitivity/specificity were assessed using calcaneal pitch as the reference standard.

RESULTS

Interrater reliability of the photographic and radiographic measures were moderate to good (intraclass correlation coefficient 0.52-0.83). However, agreement between methods was poor, with significant variability in classification (kappa < 0.40). Overall, Radiographic Arch Type had the greatest sensitivity and specificity for identifying planus, normal, and cavus feet. Among nonradiographic parameters, photographs had the greatest sensitivity and specificity for identifying normal feet, the greatest sensitivity for identifying planus feet, and the greatest specificity for identifying cavus feet.

CONCLUSION

Agreement between methods varied widely, suggesting that classification is dependent on methodology and cutoff values selected to discriminate among foot types. Specifically, nonradiographic methods failed to consistently classify foot type compared with calcaneal pitch and Meary angle.

LEVEL OF EVIDENCE: Level II, prospective cohort study.