As toddlers learn to walk and then run, the shape of their legs changes. Initially, a toddler walks with a wide-based gait, and her f legs typically look bowed — as if she just got off a horse. By two or three years of age, the base narrows, and the legs straighten out. Often the feet begin to point inward, and the knees may even knock together. The technical term for bowlegs is varus deformity and for knock-knees valgus deformity.
Most children develop straight legs with no more bowing or knocking by seven or eight years of age. But occasionally, the process is exaggerated, and the varus or valgus is extreme. This results in difficulty walking and running, causing the child to trip and fall more than other children.
Bowlegs are normal — to an extent. The legs can become too curved when one side of each leg grows more quickly than the other. When you look at your child straight on, you can draw an imaginary line down the middle of her body, starting at her head and traveling down to the space between her feet. The side of the knee closest to the line is called the medial side; the side farthest from the line is called the lateral side. With severe bowing of the legs, the lateral sides of the growth plates near the knees grow faster than the medial sides, causing the bones to curve in a C shape. This condition is called Blount’s disease.
Knock-knees evolve very differently. As the legs straighten by age two or three, increasing pressure is put on the medial sides of the feet. If a child has flat arches or has trouble distributing the weight of her body across each of her feet, the medial side will bear more of the weight, and the feet will roll in toward the midline of the body. In turn, the ankles will roll inward, and the knees will follow, “knocking” together. Often the thighs will rub together in the midline as well. Most of the time, when a knock-kneed child moves her weight onto the lateral sides of her feet (for instance, when she wears shoes with arch support), her thighs and knees will come apart, and her ankles will straighten.
What can I do?
Nothing needs to be done for normal bowlegs. For knock-knees, try putting your toddler in shoes with arch support.
When does my doctor need to be involved?
Bowing and knocking are normal — to a degree. If your child is having difficulty walking or running because of the shape or position of her legs, you’ll want your doctor to observe her in motion. Also, if the legs look different, with one significantly more bowed or knocked than the other, let your doctor know.
Remember that most bowing corrects itself by age three. If this hasn’t occurred, you may want to speak with your doctor. Severe bowing can be associated with other bony problems elsewhere in the body, such as vitamin D deficiency (also called rickets).
What tests need to he done, and what do the results mean?
Tests do not need to be done when bowlegs or knock-knees are part of the normal continuum of development. If, however, the shape is extreme or is interfering with your child’s movement, X rays may be done.
What are the treatments?
In the past, many children with bowlegs or knock-knees were put in braces or casts. Today children are treated much less aggressively because it is recognized that these treatments didn’t do much good.
For severe or persistent bowing or knocking, your doctor may recommend that your child see an orthopedist about every six months. Bracing, casting, or surgery are needed only in the most extreme cases.
What are the possible complications?
There are no complications of normal bowlegs or knock-knees. However, if the positioning does not resolve on its own, or if it becomes exaggerated, the other bones and muscles from the hips down to the feet can be affected.