Intra and inter-observer reliability and repeatability of metatarsus adductus angle in childhood. A concordance study.

Abstract Background. Metatarsus adductus is a relatively common congenital foot deformity often unrecognized at birth. There is adduction of the metatarsals, supination of the subtalar joint, and plantarflexion of the first ray. Methods: The present study aimed to assess the intra and inter-reader reliability of the radiographic metatarsus adductus measurement angles used in the literature. All consecutive patients over two years and under 12 years of age with metatarsus adductus by roentgenographic evaluation on weight-bearing dorsoplantar images were included in a cross-sectional study. Results: We identified and assessed all radiographic measurements to evaluate the Metatarsus adductus with the different measurements commonly used nowadays. Berg’s angle, Kilmartin’s angle, Laaveg & Ponseti angle, Rearfoot angle, Root’s angle and Simon’s angle. Results: The reliability of the variables measured in 32 weight-bearing dorsoplantar foot radiographs show excellent reliability ranging in Laaveg - Ponseti and rearfoot angles with low SEM, CV, and MCD with ICC higher than 0,990, Kilmartin, Root, and Simons angles showed an intra or inter reliability with ICC higher than 0,900 but systematic differences between intersession or inter observers (p<0.05) or high MCD value. Conclusion: It is more suitable to measure the MA angle with the techniques of Laaveg and Ponseti angle and rearfoot angle to show higher reliability and repeatability of Intra and inter-observer.