Bowlegs & Knock Knees (Pediatric)

What are bowlegs and knock knees?

Genu Varum is a term used to describe outward curving of the legs that occurs in almost all children. Also known as genu varum, this is part of normal development. It is actually abnormal for children less than 18 months of age not to be bowleg.

Very occasionally, children can have other problems that result in an abnormal alignment.

What causes these conditions?

Bowlegs (Genu Varum)

Because of their folded position in the uterus, normal children are born bowlegged. This actually increases until the age of 18 months, and then the legs straighten as the child grows.

Bowleg can be caused by Rickets (a metabolic disorder), Blount's Disease, trauma, a fracture healing incorrectly, and genetic bone growth abnormalities. Bowlegs, when it is not a part of normal development or due to trauma, are a symptom of a disease and not a disease itself.

If the child maintains bowlegs after 24 months of age, if the bowlegs are severe or much worse on one side or if other problems are present, we will recommend an X-ray for better evaluation.

Knock Knees (Genu Valgum)

In knock knees, the lower legs bend outward, such that when the knees are touching the ankles are spread apart.

By the time a child reaches age three or four, they develop a knock-kneed configuration (also known as genu valgum), in which their legs angle inwards. This knock-kneed pattern straightens by about age six, leaving the normal slightly knock-kneed adult alignment.

How are these conditions treated?

The huge majority of children with bowlegs and knock-knees are absolutely normal and require no treatment.

We do not use surgery, braces, therapy or special shoes as long as your child is within the normal ranges listed below. 

Children are bowlegged from birth until age 2-3. They become knock-kneed until around age 6 or 7. Most adolescents and adults are slightly knock-kneed.

Pictures of Bowlegs and Knock Knees


Diagram of normal leg alignment, bowlegs and knock knees

             Normal Condition  |  Bowlegs  |  Knock Knees   

In rare cases surgery may be recommended to correct extreme knock knees or bowlegs that cause immediate pain or difficulty walking, or that will cause arthritis later in life. Surgery is usually done at about age 10 or 11, before the child stops growing. It involves fusing or placing pins at certain growth plates so that growth may be restricted in areas that are growing faster than others.