Bowing of the legs in a toddler is not uncommon and may sometimes cause the child to trip. Most often, this is simply a variation of the normal appearance. When this is the case, it is known as physiologic genu varum. From the age of 15 to 18 months until the age of 3 years, a slow but progressive improvement usually takes place until complete correction of the problem has occurred. Generally, there is no need for any external bracing or special shoe wear.

However, there are other reasons for a child to have bowed legs. Blount's disease is a condition that can occur in toddlers (as well as in adolescents). It results from abnormal growth in the upper part of the shin bone (tibia). In a child under the age of 2 years, it may be impossible to distinguish infantile Blount's disease from physiologic genu varum. By the age of 3 years, however, progressive bowing develops, and an obvious problem can often be seen on X-ray. Unlike physiologic genu varum, Blount's disease does require treatment for improvement to occur.

• If caught early in the disease course, treatment with a brace may be all that is needed.
• If there is continued progression of the bowing despite the use of a brace, surgery may be needed to prevent further worsening and permanent damage to the growth area of the shin bone.

Unlike infantile Blount's disease, adolescent Blount's disease occurs in overweight adolescents. Brace treatment is not effective in this condition. Surgery is required to correct the problem.

Bowed legs in the toddler may also be caused by metabolic conditions such as nutritional rickets--a deficiency of vitamin D in the diet. This rarely occurs in developed countries because many foods, including milk products, are fortified with vitamin D. Rickets can also be caused by a genetic abnormality that does not allow vitamin D to be absorbed or metabolized correctly. The effects of this condition can often be controlled with medication. This form of Rickets may be inherited from the parents or it may occur spontaneously in children. Braces do not appear to be helpful for this condition. Surgery to realign the legs is often needed as the child gets older.

In most cases, your doctor can tell what is causing the bowing in your toddler's legs by asking questions and examining your child. Sometimes X-rays and blood tests are needed to make the diagnosis. In most cases of bowed legs, simple observation will lead to a diagnosis of physiologic genu varum, and the problem will resolve on its own. If treatment is required, however, the condition is usually correctable.