Bow Legs (Genu Varum) and Knock Knees (Genu Valgum)

Normally, young children often have bow legs (genu varum). While all babies have this curvature in the legs, it is more notable once the child begins to stand and walk.  This is called "physiologic genu varum".  With growth, this straightens out, usually by age 3.  From ages 3-8, children may develop a knock-kneed appearance (physiologic genu valgum).  This usually straightens out over a few years but may take until adolescence.  There is a wide range of "normal" in children and adolescents.

Occasionally some children can develop deformities that are not in keeping with normal variations in growth and these can be for multiple reasons, including metabolic conditions, abnormal pressures through the growth plates in the knee due to excess weight, and growth disturbances following trauma.  

Refer to these helpful links below for further information.

American Academy of Orthopedic Surgeons - Bowed legs