Genu Varum (Bowlegs)
Bowlegs, where the knees bow outward
Quick Facts
- Type: Lower-limb alignment condition
- Main feature: Knees apart, ankles together
- Often normal in: Infants and toddlers under about age 2
- When to assess: Severe, one-sided, painful, or worsening cases
Overview
Genu varum, commonly called bowlegs, describes a leg alignment in which the legs bow outward so that the knees stay apart even when the feet and ankles are together. It is the opposite of knock knees (genu valgum).
A degree of bowing is normal and expected in babies and toddlers, reflecting their position in the womb, and it usually corrects on its own as a child begins walking and grows, often straightening by around age two. Bowlegs that are severe, getting worse, one-sided, or present in older children and adults may signal an underlying bone, growth, or metabolic condition that deserves evaluation.
Symptoms
In most young children, the only feature is the bowed appearance of the legs, with no pain or difficulty.
- A visible gap between the knees when standing with the ankles together
- A waddling or awkward walking pattern in some children
- Knee or leg pain, more common in older children and adults
- Discomfort after prolonged walking or activity
- Uneven shoe wear
- In one-sided cases, a clear difference between the two legs
Persistent or severe bowing concentrates load on the inner part of the knee and may contribute to discomfort or, over time, joint wear.
Causes
In infants and toddlers, bowlegs are usually a normal developmental stage. Other causes include:
- Normal growth variation: The legs typically bow in infancy, straighten by about age two, swing toward knock knees in preschool years, then settle.
- Blount disease: A growth disorder of the upper shinbone that causes progressive bowing and needs treatment.
- Rickets: Vitamin D, calcium, or phosphate deficiency that softens growing bone so it bends under weight.
- Growth-plate injury: A past fracture near the knee causing uneven growth.
- Bone dysplasias: Inherited disorders affecting bone development.
- Arthritis: In adults, inner-compartment knee arthritis can gradually bow the leg outward.
Risk Factors
- Infancy and toddler years (physiologic bowing)
- Early walking combined with being overweight (raises Blount disease risk)
- Vitamin D, calcium, or phosphate deficiency
- Previous fracture near the knee involving a growth plate
- Inherited bone or growth disorders
- Inner-compartment knee osteoarthritis in adults
Diagnosis
A clinician evaluates the legs, the child's growth, and any symptoms.
- Physical exam: Measuring the gap between the knees when the ankles touch, watching the gait, and checking for one-sided differences.
- History and growth review: Age, when bowing started, family history, diet, and weight help separate normal development from disease.
- X-rays: Standing leg X-rays measure the angle and look for Blount disease, rickets, old injuries, or bone disorders, used when bowing is severe, one-sided, painful, or worsening.
- Blood tests: Vitamin D, calcium, and related tests if a metabolic cause is suspected.
Treatment
Normal infant and toddler bowing needs no treatment beyond reassurance and observation, as it straightens with growth.
- Watchful waiting: For typical, mild, symmetric bowing in young children, the clinician monitors over time.
- Treating the cause: Correcting vitamin D or mineral deficiency, or managing Blount disease, addresses the root problem.
- Bracing: In early Blount disease in young children, a brace may help guide growth.
- Weight management: Reducing excess weight lowers stress on the knees.
- Guided growth surgery: In growing children with severe or progressive bowing, a small procedure can slow growth on one side of the growth plate to let the leg straighten.
- Realignment surgery (osteotomy): In adults or after growth is complete, the bone may be cut and realigned for severe deformity or arthritis.
Prevention
- Ensure adequate vitamin D and calcium through diet, sunlight, and supplements when advised
- Maintain a healthy weight, which lowers the risk of Blount disease and knee strain
- Have growth-plate injuries near the knee assessed and followed
- Have severe, one-sided, or worsening bowing checked rather than assumed to be normal
- Stay active to support strong bones and muscles
When to See a Doctor
See a clinician if bowlegs are severe, affect only one leg, are getting worse, persist or appear after about age two to three, or come with pain, a limp, or short stature. In adults, new or worsening bowing with knee pain should be evaluated, as it may reflect inner-compartment arthritis. Sudden deformity after an injury needs prompt assessment.
Frequently Asked Questions
Are bowlegs normal in babies?
Yes, bowlegs are a normal stage in infants and toddlers, reflecting their position in the womb. The legs usually straighten on their own by around age two as the child walks and grows. Severe, one-sided, worsening, or persistent bowing should be checked.
What is Blount disease?
Blount disease is a growth disorder of the upper shinbone that causes the leg to bow outward and tends to get worse without treatment. It is more likely in children who walk early and are overweight. It is treated with bracing or surgery, so progressive bowing deserves evaluation.
Can bowlegs be fixed without surgery?
Often, yes. In young children, normal bowing usually straightens with growth, and treating causes such as vitamin D deficiency helps. Bracing can work for early Blount disease. Surgery is reserved for severe, progressive, or symptomatic cases.
Do bowlegs cause arthritis?
Mild, normal childhood bowing does not. However, severe or persistent bowing concentrates load on the inner part of the knee and, over many years, can contribute to wear in that area. Correcting significant misalignment can help reduce this stress.
References
- American Academy of Orthopaedic Surgeons (AAOS). Bowed Legs (Blount's Disease).
- Nemours KidsHealth. Bowlegs.
- MedlinePlus, U.S. National Library of Medicine. Bowlegs.
- Mayo Clinic. Rickets — Symptoms and causes.