Ponseti treated idiopathic clubfoot - outcome predictive factors in the test of time: analysis of 500 feet followed for five to 20 years

PURPOSE: To investigate a set of risk factors on the outcome of Ponseti treated idiopathic clubfeet (ICF). METHODS: This study was approved by the institutional review board. A retrospective analysis of prospectively gathered data over a 20-year period, at a single dedicated clubfoot clinic. Records of 333 consecutive infants with 500 ICF were analyzed. Initial Pirani score, number of casts, need for tenotomy, foot abduction brace compliance and functional score had been documented. The need for surgery after initial correction was the outcome measure. All children were followed by the same team throughout the study period. Descriptive statistics, chi-squared and multivariate analysis were performed. RESULTS: In total, 82 children (24%) with 119 feet (23.8%) were operated on, with 95.1% of feet being operated up to the age of nine years. There was a significant correlation between the Pirani score at presentation and the number of surgical procedures (chi-squared = 79.32; p < 0.001). Achilles tenotomy was done in 94.8% of patients. Pirani score of > 4.5 before casting was strongly associated with increased surgical risk (odds ratio = 1.95). When six to eight cast changes were needed, surgical prospect was 2.9 more, increasing to 11.9 when nine or more casts were needed. CONCLUSION: Foot severity and number of cast changes were the strongest predictors for future surgery. Estimation of the risk of deformity recurrence after initial correction may help in tailoring a cost-effective personal treatment and follow-up protocol. Personalized focused protocol will help patients and caregivers and will reduce expenses. LEVEL OF EVIDENCE: Level II - prognostic study.