Medical Conditions

Blount Disease (Tibia Vara)

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published OrthoInfo, AAP, NIH guidelines

Editorial policy

Last reviewed: June 2026

If your baby has been diagnosed with or you suspect blount disease (tibia vara), here is what the evidence says.

The short answer

Key takeaways

Blount disease (tibia vara) is an abnormal growth plate disorder of the upper tibia (shinbone) that causes progressive bowing of the legs. Unlike normal physiologic bowing that nearly all babies outgrow by age 2-3, Blount disease worsens over time and shows a characteristic "beaking" on the inner part of the tibial growth plate on X-ray. It has two forms: infantile (ages 1-3) and adolescent. Early detection is important because bracing is effective in younger children, while older children may require surgery.
Usually normal when: Your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb
Call your doctor if: Your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation
Varies by age — see the age-by-age breakdown below

“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”

— Fever and Your Child, American Academy of Pediatrics (AAP)

Parents everywhere have the same worry. You are doing the right thing by looking into it.

What Parents Should Know

According to OrthoInfo, AAP, NIH guidelines, blount disease (tibia vara) is an abnormal growth plate disorder of the upper tibia (shinbone) that causes progressive bowing of the legs. Unlike normal physiologic bowing that nearly all babies outgrow by age 2-3, Blount disease worsens over time and shows a characteristic "beaking" on the inner part of the tibial growth plate on X-ray. It has two forms: infantile (ages 1-3) and adolescent. Early detection is important because bracing is effective in younger children, while older children may require surgery. At 0-3 months, all babies are born with some degree of bowed legs from their curled position in the womb. This is entirely normal physiologic bowing. At this age, it is impossible to distinguish between normal bowing and what might eventually become Blount disease. No evaluation beyond routine well-child exams is needed unless bowing is extreme. It is generally considered normal when your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb. However, you should contact your pediatrician promptly if your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal

Worth Discussing

Your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb

Your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation

Your toddler's bowed legs are gradually straightening as they grow, walk more, and approach age 2-3

Your child has sudden leg pain with inability to bear weight after a fall, which could indicate a fracture through weakened bone

Both legs are symmetrically bowed and your child walks and runs without pain, limping, or unusual gait

Your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time

Your child is between 2-3 years old and the bowing is clearly less pronounced than it was at 12-18 months

One leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease)

By Age

What to expect by age

0-3 months

All babies are born with some degree of bowed legs from their curled position in the womb. This is entirely normal physiologic bowing. At this age, it is impossible to distinguish between normal bowing and what might eventually become Blount disease. No evaluation beyond routine well-child exams is needed unless bowing is extreme.

3-12 months

Physiologic bowing remains common and expected in this age group. As your baby begins to pull to stand and cruise, you may notice the bowing more, but this is still within the normal range. Risk factors for infantile Blount disease include early walking (before 11 months), higher body weight, and African American or Hispanic heritage. Your pediatrician monitors leg alignment at well-child visits.

1-3 years

This is when infantile Blount disease typically becomes apparent. The key distinguishing features from normal bowing are: asymmetry (one leg more bowed than the other), worsening bowing rather than improvement, and a sharp angular bow rather than a gentle curve. Your pediatrician may order standing X-rays to look for the hallmark finding of medial tibial beaking (a beak-shaped irregularity at the inner growth plate). If caught before age 3, bracing with a knee-ankle-foot orthosis (KAFO) can be very effective at correcting the alignment and avoiding surgery.

3-5 years

If Blount disease was not detected earlier, the bowing may be pronounced by this age. Children often develop a lateral thrust (the knee bows outward with each step) when walking. After age 3-4, bracing becomes less effective, and surgical correction such as a proximal tibial osteotomy or guided growth surgery using plates may be recommended. These procedures have high success rates. Without treatment, progressive bowing can lead to joint damage, leg length discrepancy, and early arthritis.

What to Tell Your Pediatrician

Describe when you first noticed blount disease (tibia vara) and how it has changed over time.
Note your baby's current age and which age-specific patterns you are seeing.
Mention if your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time.
Mention if one leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease).
Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...

Your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb
Your toddler's bowed legs are gradually straightening as they grow, walk more, and approach age 2-3
Both legs are symmetrically bowed and your child walks and runs without pain, limping, or unusual gait
Your child is between 2-3 years old and the bowing is clearly less pronounced than it was at 12-18 months

Mention at your next visit when...

Your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time
One leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease)
Your child has a sharp angular bow at the knee rather than a gentle curve along the entire leg

Act now when...

Your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation
Your child has sudden leg pain with inability to bear weight after a fall, which could indicate a fracture through weakened bone

What You Can Do at Home

Keep track of when you notice blount disease (tibia vara) — noting the time of day, duration, and any triggers can help your pediatrician.
Remember that your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb — this is generally within the range of normal.
At 0-3 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
While monitoring at home, seek immediate care if your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation.

My Baby Looks Bowlegged

Almost all babies are born with bowlegs because of how they were curled up in the womb. This is completely normal and usually corrects itself by age 2-3 as your child grows and starts walking. True bowleggedness that needs treatment is rare and usually only a concern if it's severe, gets worse over time, or affects just one leg.

My Baby's Bowed Legs Are Not Straightening

Physiological bowing (normal bowed legs) should begin straightening after age 18-24 months. If bowing persists beyond age 2, worsens, or is asymmetric (more on one side), it may indicate Blount disease, rickets, or other conditions that benefit from treatment. Most persistent bowing is treatable when caught early.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is blount disease (tibia vara) normal?

When should I call the doctor about blount disease (tibia vara)?

Your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation Your child has sudden leg pain with inability to bear weight after a fall, which could indicate a fracture through weakened bone

When is blount disease (tibia vara) normal?

Your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb Your toddler's bowed legs are gradually straightening as they grow, walk more, and approach age 2-3 Both legs are symmetrically bowed and your child walks and runs without pain, limping, or unusual gait

What causes blount disease (tibia vara)?

Blount disease (tibia vara) is an abnormal growth plate disorder of the upper tibia (shinbone) that causes progressive bowing of the legs. Unlike normal physiologic bowing that nearly all babies outgrow by age 2-3, Blount disease worsens over time and shows a characteristic "beaking" on the inner part of the tibial growth plate on X-ray. It has two forms: infantile (ages 1-3) and adolescent. Early detection is important because bracing is effective in younger children, while older children may require surgery. Common explanations include: Your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb. Your toddler's bowed legs are gradually straightening as they grow, walk more, and approach age 2-3.

What should I mention to my pediatrician about blount disease (tibia vara)?

You should mention blount disease (tibia vara) at your next visit if: Your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time. One leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease). Your child has a sharp angular bow at the knee rather than a gentle curve along the entire leg.

Is blount disease (tibia vara) normal at 0-3 months?

Is blount disease (tibia vara) normal at 3-12 months?

Should I go to the ER for blount disease (tibia vara)?

Seek emergency care if your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation, or if your child has sudden leg pain with inability to bear weight after a fall, which could indicate a fracture through weakened bone. When in doubt, call your pediatrician's after-hours line for guidance.

Does blount disease (tibia vara) go away on its own?

In many cases, blount disease (tibia vara) resolves on its own, especially when your baby is under 18 months old and both legs are equally bowed, which is typical physiologic bowing from positioning in the womb. By 3-5 years, if Blount disease was not detected earlier, the bowing may be pronounced by this age. Children often develop a lateral thrust (the knee bows outward with each step) when walking. After age 3-4, bracing becomes less effective, and surgical correction such as a proximal tibial osteotomy or guided growth surgery using plates may be recommended. These procedures have high success rates. Without treatment, progressive bowing can lead to joint damage, leg length discrepancy, and early arthritis.

ORTHOINFO AAP NIH

References

[1]American Academy of Orthopaedic Surgeons. Blount Disease (Tibia Vara). OrthoInfo, 2022. OrthoInfo
[2]American Academy of Pediatrics. Common Leg and Foot Problems. HealthyChildren.org. AAP
[3]National Institutes of Health. Blount Disease. MedlinePlus, 2023. NIH

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Blount Disease (Tibia Vara).

Things to mention

Describe when you first noticed blount disease (tibia vara) and how it has changed over time.
Note your baby's current age and which age-specific patterns you are seeing.
Mention if your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time.
Mention if one leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease).
Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

Your child is over 2 years old and the bowing does not seem to be improving, or appears to be getting worse over time
One leg is significantly more bowed than the other (asymmetric bowing is a red flag for Blount disease)
Your child has a sharp angular bow at the knee rather than a gentle curve along the entire leg

Urgent signs to report immediately

Your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation
Your child has sudden leg pain with inability to bear weight after a fall, which could indicate a fracture through weakened bone

My notes

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Bottom line

Most cases of blount disease (tibia vara) are normal. Talk to your pediatrician if your child has rapidly worsening leg bowing with pain, limping, or difficulty walking, which needs prompt orthopedic evaluation.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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