Leg alignment in children (bowed legs and knock-knees)
Many parents worry about the shape of their child’s legs, especially when they appear bowed or knock-kneed. The good news is that this is usually part of normal development, and most children grow out of it without needing any treatment.
What do "bowed legs" and "knock-knees" look like?
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Bowed legs means the knees curve outward. The medical term for bowed legs is “genu varum”.
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Knock-knees touch while feet are apart. The medical term is “genu valgum”.
Page contents
On this page you will find information about:
What to expect as your child grows
Children’s legs change shape naturally over time:
- Birth to 2 years: It is normal for toddlers to have bowed legs (knees curve outward). The medical term for bowed legs is “genu varum”.
- Around age 2 to 3: Legs often become knock-kneed (knees touch while feet are apart), peaking at about age 3. The medical term is “genu valgum”.
- By age 7: Most children’s legs settle into a normal slight knock-kneed position, similar to adults. The medical term is “valgus”.
Every child develops at their own pace. It is common for some to go through these changes a bit earlier or later than others, even up to a year outside this range.
Risk factors
Some things can increase the risk of abnormal leg alignment:
- Being overweight
- Having low vitamin D levels
- Having untreated flat feet with very flexible joints
When to go to your GP
In most cases, leg alignment improves on its own. However, a child should be checked by a doctor if:
- One leg looks different from the other.
- The bowing or knock-knee gets worse over time.
- The leg shape falls outside the expected age range for normal development.
For GPs: Referral Recommendations
In most cases, leg alignment improves on its own.
Recommendations:
- Encourage a healthy weight.
- Check vitamin D levels and treat if needed.
- Consider arch supports.
- Most importantly: monitor the leg shape over time.
Referrals:
In the following cases, a child may need to be referred to an orthopaedic specialist.
- Increasing bow legs (genu varum): Referral to orthopaedics after age 4.
- Increasing knock knees (genu valgum): Referral to orthopaedics after age 8.
- Severe cases needing guided growth: Referral to orthopaedics before age 10.
Other considerations:
If bow legs are not improving:
- Blount’s disease (a growth disorder affecting the shin bone)
- Bone injuries (trauma)
- Infections or tumours
- Rickets (soft bones due to low vitamin D)
- Genetic bone conditions (skeletal dysplasia)
If knock knees are severe or worsening:
- Bone injuries (trauma)
- Infections
- Tumours
- Rickets
- Skeletal dysplasia
Summary
- Bow legs and knock knees are a normal part of growing up.
- Most children’s legs straighten by age 7.
- Only a small number need treatment.
- See a specialist if the condition is severe, getting worse, or affecting only one leg.
- Maintaining healthy weight and good vitamin D levels can help support normal growth.