Magnetic resonance imaging of congenital talipes equinovarus treated with the Ponseti method: a short-term outcome study

Abstract

BackgroundTo quantitatively evaluate the effectiveness of the Ponseti method for the correction of clubfoot, we decided to use Magnetic resonance imaging(MRI) to evaluate changes in the tarsal bones relationship. MethodsThis is a retrospective study of 12 children with clubfoot treated with Ponseti method. MRI studies were obtained using a 3.0T machine(GE, America). T1-weighted and T2-weighted images were acquired in the standard anatomic sagittal, transverse, and coronal planes. For the measurement, the best slice that clearly demonstrated the anatomy was chosen. Sagittal talocalcaneal angle, sagittal tibiocalcaneal angle, coronal tibiocalcaneal angle, transverse talar neck angle, transverse talonavicular angle and transverse talocalcaneal angle were measured. The 15 corrected clubfoot were compared with the 9 unilateral normal feet at clinical and radiological levels using a Pirani scoring system and MRI, respectively.Results12 patients (10 boys, 2 girls) with clubfoot were examined by using MRI. 9 cases had unilateral and 3 had bilateral involvement(8 left clubfoot, 7 right clubfoot), giving a total of 15 clubfoot compared with 9 normal feet. The mean age of patients at examination was 47.7months (8-96 months). The recovery of the corrected clubfoot in these patients met the goals of Ponseti treatment(functional, normal looking, pain-free, plantigrade foot). Before Ponseti treatment, the mean Pirani score of clubfoot was 5.5(5-6). During this follow-up, the Pirani score was 0.07(0-0.05). The results of MRI indicated that only the transverse talonavicular angle showed significant difference between the treated clubfoot and the normal feet(P< 0.001). 1 of 15 of the corrected clubfoot had dorsal talonavicular subluxation in sagittal plane and 1 had lateral subluxation of the navicular in transverse plane, which have never been reported in previous studies.ConclusionsAlthough the appearance and function of clubfoot recovered well after the Ponseti method, the results of MRI indicated that Ponseti method successfully corrected the varus, cavus, and equinus deformities and incompletely corrected the adduction deformity regarding transverse talonavicular angle. At the same time, the Ponseti method may cause dorsal talonavicular subluxation in sagittal plane and lateral subluxation of the navicular in transverse plane on MRI.