Early Radiographic Characteristics of the Lateral Talocalcaneal Angle and its Predictive Significance for Relapse in Patients With Idiopathic Clubfoot Treated With the Ponseti Method

In order to evaluate the early radiographic characteristics of the lateral talocalcaneal (L-TC) angle in patients with idiopathic clubfoot (ICF) and to investigate its prognostic significance for relapse after initial treatment with the Ponseti method. We retrospectively included 151 patients (96 males and 55 females; 227 feet) with ICF treated at our Institution between January 2005 and December 2014. The age at initial treatment was less than 6 months, and radiographs were obtained within 3 months of the Achilles tenotomy (mean age: 2.3 months; range: 0.77-6.8). All patients were followed up for at least 7 years (range, 7-18). The participants’ feet were classified into 3 groups: relapsed (Group A), not relapsed (Group B), and normal foot groups which consisted of healthy feet in patients with unilateral ICF (Group C). All angle measurements were expressed in degrees. Forty-seven ICF feet in 33 patients relapsed, while 180 feet in 118 patients did not, and the age at relapse was 5.92 ± 1.91 years. Seventy-five normal feet were included in Group C. The average L-TC angle in Group A and B patients was 33.57° ± 12.05° and 39.37° ± 12.55°, respectively, while Group C was 49.61° ± 9.11°. A significant difference was found among the 3 groups of patients (F = 31.48, p < .001). The L-TC angle cut-off value below which a recurrence could be predicted was 36.1° (sensitivity, 74.47%). The L-TC angle of ICF patients treated using the Ponseti method were reduced compared to normal feet. An L-TC angle of <36.1° has relative value in predicting ICF relapse.