Predictive value of Pirani scoring system for tenotomy in the management of idiopathic clubfoot

Purpose: To determine the predictive value of the Pirani scoring system in the need for tenotomy using the Ponseti method for management of idiopathic clubfoot. Method: This is a prospective observational study involving patients less than 2 years of age with idiopathic clubfoot. The consenting parents and institution ethical board approved the study. The relationship between Pirani scores and the need for tenotomy was evaluated using the independent t-test and the binary logistic regression to predict the need for tenotomy. Pearson’s r and Cohen’s κ were used to measure correlation and agreement, respectively, between the predicted and observed values. A receiver operating characteristic curve was used to interpret sensitivity and specificity levels as well as to obtain a cutoff score for predicting the requirement for tenotomy. Results: Eighty-four clubfeet from 50 patients were studied. Thirty-eight feet (45%) had percutaneous tenotomy. The initial total Pirani and hindfoot scores were found to predict the need for tenotomy with the model for prediction being able to predict correctly in 72.6% and 75% of the time, respectively. A higher Pirani score was associated with higher odds of requiring tenotomy (OR = 4.402, p < 0.001) and total Pirani score above the cutoff point of 4.75 predicted the need for tenotomy. Conclusion: The indication for tenotomy appears to be well predicted using the Pirani scoring system with the odds of requiring a tenotomy increasing by more than fourfold for every unit increase in Pirani score.