Are Bow Legs Normal in Toddlers, and When Do They Straighten?

What are bow legs in a toddler?

Bow legs, known medically as genu varum, describes a visible outward curve at the knees when a child stands with their ankles together. The knees stay apart, creating a gap. In medical terms, the distance between the inner edges of the knees is called the intercondylar distance.

Nearly all newborns have some degree of leg bowing. This is called physiological bowing, and it happens because of the baby's folded position inside the womb during the last weeks of pregnancy. It is not a sign of a problem. It is simply how the bones develop before birth.

As your child starts to walk and bear weight through their legs, the bones gradually remodel. This is a normal, predictable process. Many children then pass through a brief phase of knock knees before the legs settle into their adult alignment.

When do bow legs straighten in children?

Most bow legs straighten on their own between the ages of two and four. By the time a child is around 18 to 24 months old, the curve typically starts to reduce. By age three to four, the legs are usually straight or even slightly knock-kneed, which is also normal at that stage.

The process is gradual. You might not notice changes week to week, but over several months the gap at the knees closes. No treatment is usually needed. Your GP or health visitor may suggest watchful waiting, which simply means keeping an eye on the shape over time.

If the bowing has not started to improve by age two, or if it is clearly getting worse rather than better, that is a good reason to seek a specialist opinion.

What signs suggest bow legs might not be normal?

In most toddlers, bow legs need no intervention at all. However, certain features can suggest that the bowing is not purely physiological and may benefit from further assessment.

What causes bow legs in babies and toddlers?

The most common cause is simply normal development. In a small number of children, the bowing has a different origin that may need monitoring or treatment.

Other rare causes include skeletal dysplasia and previous fractures near the knee. Your GP can usually tell the difference between normal bowing and something that needs investigation based on your child's age, the severity of the curve, and whether it is changing over time.

How does a standing scan help assess bow legs?

A standing, weight-bearing scan captures your child's leg alignment exactly as it works in real life, while gravity is pulling on the joints and bones. This matters because lying-down imaging relaxes the muscles and can make the legs look straighter than they really are, potentially hiding the true extent of the bowing.

EOS imaging, available through ScanAlign, low dose standing imaging, takes a full-length image of both legs in a single standing exposure. This gives the clinician a clear picture of the overall alignment from hips to ankles, not just a small section of one bone. Read more about bow legs and knock knees on a standing scan.

Importantly, an EOS scan uses about 90% less radiation than a standard X-ray, around ten times less. For children, reducing radiation exposure is a real priority, and low-dose imaging makes parents and clinicians more comfortable with the assessment.

Frequently asked questions about bow legs in toddlers