Ultrasound measurements in clubfoot treated with the Ponseti method and risk factors for recurrence: A retrospective study

Background: Recurrence remains the main challenge in the treatment of clubfoot. The primary goal of this study is to determine if ultrasound measurements are associated with recurrence after successful management with the Ponseti method. Furthermore, other factors are identified which can be associated with recurrence of the deformity. Methods: Seventy-six infants (114 idiopathic clubfeet), all treated with the Ponseti technique were reviewed. All patients had an ultrasound evaluation by the same radiologist at the beginning of the treatment. Recurrence, defined as the need to return to Ponseti casting, was recorded at a mean follow-up of 5 years. Measurements of association with recurrence were obtained for the following ultrasound measures: the medial talonavicular displacement (MTa-N), the medial malleolus to navicular distance (MM-N), the talocalcaneal angle (Ta-C), and the distal tibial physis to proximal calcaneal apophysis distance (Ti-C). Subsequently, a multivariate logistic regression analysis modeling recurrence examined patients' characteristics, compliance, Achilles tenotomy, and ultrasound measurements. Results: Recurrence rate was 22% noted in 17 patients. On univariate analysis, relapse was associated with increased MTa-N (p = 0.038), decreased MM-N (p = 0.008), and decreased Ti-C (p = 0.023). On multivariate analysis, we identified the Ti-C as the only ultrasound measurement significantly associated with recurrence (p= 0.026). Other significant predictors for relapse in this study were noncompliance with orthosis (OR= 139.0 (95% CI: 8.7-2224.0), p< 10(-3)), and omitting percutaneous Achilles tenotomy in clubfoot treatment (OR = 23.9 (95% CI: 1.2-493.6), p = 0.041). Conclusion: The Ti-C sonographic measurement at the start of treatment can be a useful adjunct to help identify high-risk patients for recurrence of deformity. Non-compliance with bracing and omitting percutaneous Achilles tenotomy are also predictive factors.