Physiological knee valgus is generally more common but not severe, the child has a normal diet, is in good health, the age of onset is usually between 2 and 6 years and developmental indicators such as height are normal. The lower extremities are symmetrical and the knee buckles to a lesser extent.
Pathological knee valgus is relatively uncommon, often with a clear family history, often with other skeletal and muscular disorders, and the deformity tends to worsen progressively. Both lower limbs tend to be asymmetrical, with a relatively high degree of internal knee buckling.