MR findings of bowlegs in toddlers.

BACKGROUND: Toddlers with severe physiologic tibial bowing are considered to be at risk for the development of Blount's disease. Objective. To correlate MR findings of the knee with the clinical outcome in toddlers with severe physiological tibial bowing.

MATERIALS AND METHODS: MR findings were evaluated in 22 affected legs of 14 children with severe tibial bowing (mean age 1.9 years). In 18 affected legs, MR findings were compared with the transition of the tibial metaphyseal-diaphyseal angle (MDA) and tibiofemoral angle (TFA) measured serially between 2 and 3 years of age.

RESULTS: MR findings of severe tibial bowing comprised undulation of the posteromedial physis of the tibia (3/22), signal alterations in the medial tibial metaphysis (10/22), T2 prolongation in the posteromedial tibial epiphyseal cartilage (14/22) and signal changes in the medial menisci (18/22). The decrease in the TFA was different in the legs with and without increased signal in the epiphyseal cartilage, and the decrease in the MDA was different in the legs with and without physeal undulation.

CONCLUSION: MR imaging findings can predict the retarded resolution of tibial bowing, which may be a risk factor for the development of Blount's disease.