What is bowlegs?

Bowlegs (genu varum) is a condition in which a child’s legs curve outward at the knees. When a child with bowlegs stands with their toes pointing forward, their ankles may touch but their knees remain apart.

On the left is a child with typical development. On the right is a child who has bow legs.

Bowlegs is considered a normal part of growth in babies and toddlers. In young children, bowlegs is not painful or uncomfortable and does not interfere with a child’s ability to walk, run, or play.

Children typically outgrow bowlegs some time after 18-24 months of age. In rare cases, bowlegs may be a sign of a growth disorder.

How do children’s legs and knees develop?

  • Bowlegs in infants: Bowleggedness often occurs between birth and 24 months.
  • Toddlers: Between about 24 and 36 months, toddlers’ legs become aligned.
  • Young children: When they’re between 3 and 5 years old, children may develop knock knees, a condition in which the knees tilt inward.
  • As children grow, their legs continue to straighten out. By age 7 to 8, or occasionally closer to the teens, children’s walking patterns typically become normal or near-normal.

This is an illustration of a toddler with bowlegs at 1 year, knock knees at 3 years, and straight alignment at 12 years.

Stages of development

What are the symptoms of bowlegs?

  • knees curve outward
  • both legs have a similar curve (symmetric)
  • awkward walking pattern
  • toes point inward (known as intoeing)
  • clumsiness or frequent tripping

What causes bowlegs?

Bowlegs often develop in the child’s first year as part of natural growth for no known cause. Some babies are born with bowlegs. This can happen as the baby grows and the space inside their mother’s womb gets tighter, causing the leg bones to curve slightly. In most cases, children’s legs straighten out as they grow and develop.

Certain conditions, such as Blount’s disease, metabolic disorders, and bone malformations, may cause a child’s legs to bow.

  • In Blount’s disease, the shinbone (tibia) in one or both of the legs grows abnormally, causing a sharp curve below the knees. Unlike bowlegs, Blount’s disease gets worse over time.
  • Some metabolic disorders, such as rickets, can also cause bowlegs. Rickets occurs when a child does not get enough vitamin D in their diet. The shortage of vitamin D weakens a child’s bones, causing their legs to bow.

When should parents be concerned about bowlegs?

If your child has bowlegs along with any of the following symptoms, they may have a more serious condition:

  • bowlegs that continue to get worse after the age of 2
  • asymmetric appearance of the bowing
  • limp when walking
  • knee or hip pain
  • short stature (below the fifth percentile)

If your child has any of these symptoms, talk to their pediatrician or an orthopedic specialist.

How we care for bowlegs at Boston Children’s Hospital

As a national and international orthopedics referral center, our Orthopedic Center has vast experience managing all aspects of bowlegs. Our Lower Extremity Program offers comprehensive assessment, diagnosis, and treatment for children and young adults with conditions affecting their lower limbs. We have extensive experience treating disorders of the feet, ankles, knees, legs, and hips. Whether the patient is an infant, child, or adolescent, our goal is to help our patients live full, independent lives.