About Genu Varum (Bow Legs)

What is Genu Varum?

Genu varum, also known as bow legs, is a condition in which the legs curve outward at the knees. When a person stands with the ankles together, there may be a noticeable gap between the knees. Bowing is common in infants and toddlers and is often part of normal development. It usually improves as the child grows and typically resolves by about age 2 to 3 without treatment.

In older children and adolescents, persistent bow legs may be caused by underlying health conditions such as rickets. Excess weight or obesity can lead to Blount’s disease, which includes bow legs.

Genu varum can affect the appearance and walking ability of individuals and may lead to knee pain in severe cases. Treatment depends on the cause, age, severity, symptoms, and progression; many cases only need observation, while others may need treatment of an underlying condition, bracing, guided growth, or surgery.

What Causes Genu Varum?

In infants and toddlers, genu varum is often part of normal lower-limb development. This is called physiologic genu varum. It usually begins to improve as the child grows and often resolves by about age 2 to 3 without treatment.

Bowing that persists after about age 2 to 3, gets worse, affects one leg more than the other, or causes pain or limping may have an underlying cause. Possible causes include:

• Blount disease: This condition affects the growth plate at the upper part of the shinbone, near the knee. It can occur in young children or adolescents and may cause progressive bowing, sometimes with inward twisting of the lower leg.
• Rickets or other metabolic bone disease: Rickets weakens growing bones and can lead to bone deformities such as bow legs. It may be caused by low vitamin D, calcium, or phosphorus, or by inherited problems with how the body uses these nutrients.

Risk factors and associated conditions may include:

• Family history: Some causes of bowing, including certain bone-growth conditions, can run in families.
• Certain medical conditions: Skeletal dysplasias, injuries or infections that affect a growth plate, and rare congenital differences in the shinbone can contribute to bow legs.

A balanced diet with enough vitamin D, calcium, and phosphorus supports healthy bone growth. Maintaining a healthy weight may also reduce stress on the knees. A healthcare professional can help determine whether bowing is part of normal development or related to an underlying condition.

How is Genu Varum Diagnosed?

Diagnosis usually starts with a medical history and physical examination. A healthcare professional may check the child’s age, growth pattern, leg alignment, gait, pain, whether one or both legs are affected, and whether the bowing is improving or worsening.

• Physical examination: The healthcare professional may observe standing posture and walking pattern, compare both legs, and measure the distance between the knees when the ankles are together.
• Imaging: X-rays may be recommended if bowing is severe, worsening, one-sided, painful, or persists beyond the expected age range. Standing X-rays of the legs can help assess alignment and look for conditions such as Blount disease or rickets.

Additional evaluation may be done when an underlying condition is suspected:

• Measurements: Measuring the distance between the knees and tracking changes over time can help monitor whether bowing is improving, stable, or getting worse.
• Thigh-foot angle: This measurement helps assess inward or outward twisting of the lower leg, which can affect how bowed legs appear.
• Weight-bearing alignment: A standing assessment or X-ray can show how the hips, knees, and ankles line up and how much stress is placed on the knee joints.
• Gait evaluation: The healthcare professional may look for a limp, asymmetry, inward or outward foot position, or a sudden outward shift of the knee while walking.

If rickets or another metabolic bone condition is suspected, blood tests may be ordered. A healthcare professional can determine which examinations or tests are appropriate based on age, symptoms, growth, and exam findings.

How is Genu Varum Treated?

Treatment for genu varum depends on the cause, age, severity, symptoms, and whether the bowing is improving or getting worse. Many infants and toddlers with physiologic genu varum only need observation and regular follow-up as the legs straighten with growth.

• Treating an underlying condition: If bowing is caused by rickets or another metabolic bone condition, treatment may include correcting vitamin D, calcium, or phosphorus problems. The exact treatment depends on the cause.
• Physical therapy or exercise: Exercises may help improve strength, balance, walking pattern, and symptoms, but they generally do not correct bone alignment when genu varum is caused by a structural bone problem.
• Bracing or orthotics: In selected children with Blount disease, bracing may be considered, especially when the condition is diagnosed early and the deformity is not severe.
  • Guided growth: In children who are still growing, a surgeon may place a small plate or screws near a growth plate to gradually guide the leg into better alignment as the child grows.
  • Corrective surgery: Severe, progressive, persistent, or symptomatic bowing may require surgery, such as an osteotomy, to realign the bone. The choice of treatment depends on growth remaining, the underlying cause, and the degree of deformity.
• Healthy habits: Maintaining a healthy weight can reduce stress on the knees and may be part of the overall care plan.

A healthcare professional can help decide whether observation, treatment of an underlying condition, bracing, guided growth, or corrective surgery is appropriate.