There is normal physiological inversion and valgus in children: inversion is present up to the age of 2 years, with the most severe inversion occurring between the ages of 6 and 12 months. As the child walks upright, the inversion gradually grows to a neutral position, and by the age of 4 years, the knee presents with maximum valgus. It does not return to a normal neutral line of force until adolescence.