Variability between Clarke's angle and Chippaux-Smirak index for the diagnosis of flat feet

Cristina González Martín,Teresa Seoane Pillado,Salvador Pita Fernández,Vicente Gil Guillen,Sonia Pertega Díaz,Beatriz López Calviño

doi:10.25100/cm.v48i1.1947

Abstract

The measurements used in diagnosing biomechanical pathologies vary greatly. The aim of this study was to determine the concordance between Clarke's angle and Chippaux-Smirak index, and to determine the validity of Clarke's angle using the Chippaux-Smirak index as a reference. Observational study in a random population sample (n= 1,002) in A Coruña (Spain). After informed patient consent and ethical review approval, a study was conducted of anthropometric variables, Charlson comorbidity score, and podiatric examination (Clarke's angle and Chippaux-Smirak index). Descriptive analysis and multivariate logistic regression were performed. The prevalence of flat feet, using a podoscope, was 19.0% for the left foot and 18.9% for the right foot, increasing with age. The prevalence of flat feet according to the Chippaux-Smirak index or Clarke's angle increases significantly, reaching 62.0% and 29.7% respectively. The concordance (kappa I) between the indices according to age groups varied between 0.25-0.33 (left foot) and 0.21-0.30 (right foot). The intraclass correlation coefficient (ICC) between the Chippaux-Smirak index and Clarke's angle was -0.445 (left foot) and -0.424 (right foot). After adjusting for age, body mass index (BMI), comorbidity score and gender, the only variable with an independent effect to predict discordance was the BMI (OR= 0.969; 95% CI: 0.940-0.998). There is little concordance between the indices studied for the purpose of diagnosing foot arch pathologies. In turn, Clarke's angle has a limited sensitivity in diagnosing flat feet, using the Chippaux-Smirak index as a reference. This discordance decreases with higher BMI values.

Highlights

Clinical practice is affected by variability and uncertainty in the process of taking therapeutic and prognostic decisions, and when taking decisions with regard to diagnosing the presence or absence of a given pathology[1]
The prevalence of flat feet according to the Chippaux-Smirak index de 19.0% y 18.9%, incrementándose con or Clarke's angle increases significantly, reaching 62.0% and 29.7% la edad
Variability may be present in practically every stage of the process, affecting the field of podology, as there are diagnostic tests that are modified by the variability of the observers and the different tests that confirm the presence or absence of the pathology

Summary

Introduction

Clinical practice is affected by variability and uncertainty in the process of taking therapeutic and prognostic decisions, and when taking decisions with regard to diagnosing the presence or absence of a given pathology[1]. A series of parameters have been used to study the pathology and morphology of the foot, such as angles, indices and lines obtained from the footprint. El objetivo de este estudio concordance between Clarke's angle and Chippaux-Smirak index, and fue determinar la concordancia entre el ángulo de Clarke y el índice. Clarke’s angle, Flatfoot, Foot, Sensitivity and Specificity, review approval, a study was conducted of anthropometric variables, Tras el consentimiento informado del paciente y la aprobación del Anthropometry, Podiatry Charlson comorbidity score, and podiatric examination (Clarke's angle comité de ética, se estudiaron variables, antropométricas, índice and Chippaux-Smirak index). Descriptive analysis and multivariate de comorbilidad de Charlson y un examen podológico

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