Reliability of the talocalcaneal angle for the evaluation of hindfoot alignment. / Fiabilidad del ángulo astrágalo-calcáneo para la evaluación de la alineación del retropié.

INTRODUCTION: Recent studies suggest that hindfoot deformity should be considered in the surgical treatment of tarsal coalitions. Many authors have used the angle between the talus and the calcaneus (TCA) for decision-making. However, its reliability has not been demonstrated and the measurement technique has not been standardized. The objective of this study was to standardize the TCA measurement technique, and to evaluate the inter and intra-observer reproducibility of the proposed technique. METHODS: The foot CT scans of a group of 30 patients between 10 and 17 years of age were analysed. Ten patients had talocalcaneal coalitions, ten calcaneonavicular coalitions and ten had no coalitions. The inter and intra-observer reproducibility of the TCA was evaluated by the intraclass correlation coefficient (ICCs). A mixed-effects ANOVA model was used to calculate the ICCs for ICC2 agreement (A, 1). This procedure was applied to the three observers (inter-observer variability), and to the test-retest of observer 1 (intra-observer variability). A two-tailed p value of ≤.05 was considered significant. RESULTS: The inter-observer and intra-observer agreements were excellent for the TCA. Inter-observer agreement: ICC2 (A, 1)=.95 (p<.001, CI 95%: .77-.93). Intra-observer agreement: ICC2 (A, 1)=.99 (p<.001, CI 95%: .97-.99). CONCLUSION: The TCA is a reliable way to evaluate hindfoot alignment. This method of measurement, as described in this study, can be safely used for surgical planning in patients with tarsal coalitions.

Fiabilidad del ángulo astrágalo-calcáneo para la evaluación de la alineación del retropié / Reliability of the talocalcaneal angle for the evaluation of hindfoot alignment

Introducción: Estudios recientes sugieren que en el tratamiento quirúrgico de las coaliciones tarsianas debería considerarse la deformidad del retropié. El ángulo entre el astrágalo y el calcáneo (AAC) es comúnmente utilizado para la toma de decisiones. Sin embargo, no se ha demostrado su fiabilidad ni se ha normalizado la forma de emplearlo. El objetivo de este estudio fue estandarizar la técnica de medición del AAC y evaluar la reproducibilidad inter- e intraobservador de la técnica propuesta. Métodos: Se analizaron 30 tomografías de pie de 27 pacientes de entre 10 y 17 años de edad. Diez presentaban coaliciones calcáneo-escafoideas, 10 coaliciones astrágalo-escafoideas y 10 sin coaliciones. La reproducibilidad inter- e intraobservador del AAC fue evaluada mediante el coeficiente de correlación intraclase (ICC). Utilizamos un modelo de ANOVA de efectos mixtos para calcular los ICC para acuerdo ICC2(A,1). Este procedimiento se aplicó a los tres observadores (variabilidad interobservador) y a la prueba-reprueba del observador 1 (variabilidad intraobservador). Un valor de p a dos colas ≤0,05 fue considerado como significativo. Resultados: Los acuerdos interobservador e intraobservador fueron excelentes para el AAC. Acuerdo interobservador: ICC2(A,1)=0,95 (p<0,001, IC 95%: 0,77-0,93). Acuerdo intraobservador: ICC2(A,1)=0,99 (p<0,001, IC 95%: 0,97-0,99). Conclusión: El AAC representa un medio fiable para evaluar la alineación del retropié. Este método de medición, tal cual se describe en este estudio, puede ser utilizado de forma segura para el planeamiento quirúrgico en pacientes con coaliciones tarsianas

Introduction: Recent studies suggest that hindfoot deformity should be considered in the surgical treatment of tarsal coalitions. Many authors have used the angle between the talus and the calcaneus (TCA) for decision-making. However, its reliability has not been demonstrated and the measurement technique has not been standardized. The objective of this study was to standardize the TCA measurement technique, and to evaluate the inter and intra-observer reproducibility of the proposed technique. Methods: The foot CT scans of a group of 30 patients between 10 and 17 years of age were analysed. Ten patients had talocalcaneal coalitions, ten calcaneonavicular coalitions and ten had no coalitions. The inter and intra-observer reproducibility of the TCA was evaluated by the intraclass correlation coefficient (ICCs). A mixed-effects ANOVA model was used to calculate the ICCs for ICC2 agreement (A, 1). This procedure was applied to the three observers (inter-observer variability), and to the test-retest of observer 1 (intra-observer variability). A two-tailed p value of ≤.05 was considered significant. Results: The inter-observer and intra-observer agreements were excellent for the TCA. Inter-observer agreement: ICC2 (A, 1)=.95 (p<.001, CI 95%: .77-.93). Intra-observer agreement: ICC2 (A, 1)=.99 (p<.001, CI 95%: .97-.99). Conclusion: The TCA is a reliable way to evaluate hindfoot alignment. This method of measurement, as described in this study, can be safely used for surgical planning in patients with tarsal coalitions