Bowlegs

What is bowlegs?

Children with bowlegs, when standing straight with toes pointed forward, have ankles that touch but knees that do not. Bowlegs is a condition involving the shin and thigh (tibia and femur) bones. Having bowlegs is considered a normal part of growth in young children, as are "knock-knees," in which both knees point inward. Bowlegs usually go away on their own by the time your child is four or five years old, or sometimes as old as eight years old.

But if your child remains bowlegged, it may be a sign of an underlying bone disease, such as Blount's disease or rickets, which is caused by a Vitamin D deficiency.

A look at the difference between normal legs and bowlegs.

Should I be concerned with my baby's progress in walking?

Below are considered average developmental milestones in your baby's ability to walk:

  • 6-10 months — most babies learn to pull themselves up to a standing
  • 7-13 months — most babies will be moving about while holding on to furniture for support. Babies can walk with support from a parent (but don't force them into walking on their own).
  • 11-14 months — most babies will start to walk on their own, usually by 14 months.
    Your child, like most children, was probably born with bowlegs, which usually straighten themselves out as your child gets older.

What causes bowlegs in children?

Most often, bowlegs develop as part of natural growth, although certain conditions, such as Blount's disease and bone malformations present at birth, may cause a child's legs to bow. In Blount's disease, your child's shin bone (tibia) grows abnormally, causing a sharp curve below the knees. A child with Blount's disease is forced to walk with the affected knee flexed, which increases bowing of the leg. This can lead to severe knee joint problems. Blount's disease is more likely to affect female children, African-American children, obese or short children, or children who walk at an early age.

Some metabolic disorders, such as rickets, a disease caused by Vitamin D deficiency, can also cause bowlegs. This occurs when Vitamin D deficiency affects and weakens a child's bones, causing the legs to bow.

How Boston Children's Hospital approaches bowlegs

Bowlegs cannot be corrected permanently without first treating the underlying cause for the condition. In the meantime, doctors at Children's try to make sure that your child's legs can straighten themselves naturally. If this doesn't work, doctors may require your child to wear corrective leg braces. Only the most severe cases would require surgery.