Bowlegs are common in toddlers and young children. A bowlegged condition is also known as tibia varum (singular) or tibia vara (plural).
The condition is considered physiologic when it’s a normal variation. In those cases, the child will grow out of it. Most toddlers have bowlegs from their position while in the uterus. This curvature stays until the muscles of the lower back and legs are strong enough to support them while standing up.
In some cases, abnormal growth of the bone causes the bowing to get worse instead of better over time. This condition is called Blount disease or pathologic tibia varum.
Blount disease becomes obvious between the ages of two and four as the bowing gets worse. Being overweight for height and body type is a major factor in Blount disease. An accurate measure of obesity is the body mass index (BMI). If your child has a BMI of 22 or higher, nutritional counseling is advised.
A second measure used to predict Blount disease is the tibial metaphyseal-diaphyseal angle (TMDA). This angle is viewed on X-rays of the lower leg. A TMDA of 10 degrees or more requires a second look.
Combining BMI with TMDA can help predict which children will need early treatment. Your doctor may have already taken these factors into consideration when advising you to take a wait-and-see approach. You may want to make a follow-up appointment to discuss your concerns.