Clubfoot classification: correlation with Ponseti cast treatment.

BACKGROUND: Many different clubfoot classification systems have been proposed, but no single one is universally accepted. Two frequently cited systems, developed by Dimeglio/Bensahel and Catterall/Pirani, are often used for evaluation purposes in the treatment of idiopathic clubfoot. Our hypothesis was that the initial scores would be positively correlated with the number of casts required for clubfoot correction, indicating to us that the more severe score would require more casts, and therefore truly show the accuracy and usefulness of the scoring system.

METHODS: From May 2000 to April 2008, 123 patients (185 feet) with idiopathic clubfeet were treated. All patients were below 60 days of age (mean 15.3 d, range: 2 to 57 d) at the time of their initial evaluation, and had not received prior clubfoot treatment. All cast placements were under the supervision of the same pediatric orthopedic surgeon. Initial correction was achieved in all patients.

RESULTS: The mean number of casts required for correction was 5.1 (range: 2 to 8). On the basis of number of casts required, no significant differences were found in final total scores (Dimeglio/Bensahel P=0.14 and Catterall/Pirani P=0.44), indicating a similar level of correction for all feet. The Dimeglio/Bensahel and Catterall/Pirani classification systems were both similarly, poorly correlated with the number of casts needed [Spearman rank correlation coefficients (rs)=0.34 vs. 0.33]. The 2 components with the highest correlations were equinus (rs=0.39) and forefoot adduction (rs=0.35) for the Dimeglio/Bensahel system and coverage of the lateral head of the talus (rs=0.40) and rigid equinus (rs=0.39) for the Catterall/Pirani system.

CONCLUSIONS: When using the initial scores, both the Dimeglio/Bensahel and Catterall/Pirani classification systems had a low correlation with the number of Ponseti casts required. Analysis of the individual components revealed variability in the coefficients, with some having low-to-moderate correlation and others having none. There was no difference between the Dimeglio/Bensahel and Catterall/Pirani classification systems when measuring their correlation with the number of Ponseti casts required for clubfoot correction. An improved classification system is needed to predict the length of treatment and, ultimately, the risk of recurrence.

LEVEL OF EVIDENCE: Prognostic Level IV.