Análisis tomográfico de la alineación del retropié en pacientes con coaliciones tarsianas

Background: The aim of this study is to analyze the hindfoot alignment with computed tomography (CT-scan) in patients with tarsal coalitions. Materials and Methods: Eighty-five patients (78 feet) between 9 and 17 years of age were included and divided into 3 groups: A) without coalitions (control group, N 29 ), B) with calcaneal-navicular coalitions (CNC group, N 31), and C) with talo-calcaneal coalitions (TCC group, N 25). Five measurements were assessed: Inftal-Suptal, Inftal-Hor, Inftal-Supcal, Suptal-Infcal, and Talo-calcaneal angle (TCA). Results: Demographic data revealed no differences between groups with respect to patient’s age and sex (p = 0.3630 and 0.2415 respectively). Patients with tarsal coalitions presented significantly higher values ​​in all measurements compared to the control group (p = <0.05 Kruskall-Wallis / ANOVA). TCA measurements in the patients with CNC and TCC were significantly superior to the control group (10.09 ± 4.60, 17.77 ± 11.28 and 28.66 ± 8.89 respectively, p = <0.0001). TCA distribution in the patients with CNC presented great variability, while group 3 (TCC) presented mostly a valgus alignment pattern. We did not find a direct correlation between the TCA and Inftal-Hor values ​​(Spearman 0.27013, p = 0.1916). Conclusion: Patients with tarsal coalitions show an increased valgus orientation of the hindfoot. The deformity is greater in patients with TCC, while in those with CNC demonstrated a great variability. The increase in the hindfoot valgus does not necessarily indicate an increase in the inclination of the subtalar joint, so the latter must be evaluated separately at the time of preoperative planning.  Level of Evidence: III