 Radiographic measurement of Drennan’s metaphyseal-diaphyseal angle. The metaphyseal-diaphyseal angle (MDA) is measured from a perpendicular line to the tibial diaphyseal axis and a line passing through the axial plane of the proximal tibial metaphysis. An MDA > 10 degrees associated with a tibiofemoral angle > 20 degrees indicates a toddler at risk. MDA: Metaphyseal-diaphyseal angle.