When to worry about bowlegs in toddlers and growing children

Posted: February 7, 2020

Your baby's legs will change as they grow. Bowlegs and knock-knees are a normal part of their child's development. But how do you know when it's just a phase – and when is it something to worry about?

What is a bowlegged baby?

A bowlegged baby stands or walks with knees farther apart than their ankles, giving the appearance of having just stepped off a horse. It is called "varus" alignment. On the opposite side of the spectrum, a person with knock-knees walks with knees touching, even when their feet are apart. This is called "valgus" alignment. [caption id="attachment_14584" align="alignright" width="450"] Babies are typically bowlegged because that's the way our legs naturally develop. Over time, our legs straighten as we bear weight and grow taller.[/caption]

Bowlegs and knock-knees are usually part of normal development.

Babies are typically bowlegged because that's the way our legs naturally develop. Over time, our legs straighten as we bear weight and grow taller. Then, children tend to become knock-kneed from ages 2-4. Their legs gradually straighten again to the expected few degrees of knock-knee that we have as adults. "So, bowlegs in a 13-month-old is usually normal, but bowlegs in a 3-year-old is not," said Dr. Rachel Randall, Marshfield Children's pediatric orthopedic surgeon. "On the other hand, noticeable knock-knees in a 3-year-old is usually normal, but significant knock-knees in a 10-year-old requires investigation of an underlying cause." In some cases, influencing factors to abnormal bone growth include:

• Genetics
• Rickets
• Blount's disease (a growth disorder of the shinbone)
• Injuries to the bone
• Radiation treatments for cancer or infection around the growth plates

Depending on the cause, the deformity can be seen on both or just one leg.

When to worry about bowlegs in toddlers

While most children grow out of it, there are signs that may indicate a more serious issue. These include:

• Extreme curvature
• It affects only one leg
• It happens later in childhood
• It becomes more noticeable over time

In addition to an exam and reviewing your family medical history, the pediatrician will assess your child's bone structure with a standing alignment X-ray. Sometimes a diagnosis isn't possible during the first examination because we need to see whether the deformity is progressing over time. It's helpful to see how the child walks over a few months, especially if a thrust develops. "I often ask parents to take videos of their children walking at home so we can compare over time to determine if the deformity is getting better or worse," Randall said.

How to correct bowlegs in babies and children

"In growing children, we have the ability to ‘guide growth' by doing a surgical procedure that allows us to tether the side of the growth plate that is growing too fast," Randall said. This allows the child's limb to straighten and correct as they grow. In more severe cases or if the growth plate is damaged, the surgeon will remove or add a wedge in order to make the limb straight. This also is the treatment in adults. Randall advises that bracing is not effective at correcting bowleg and knock-knees. Adults are at an increased risk for knee injuries or osteoarthritis if abnormal alignment isn't treated. "Think of the cartilage in your knees like a tread on a tire. If the tire is out of alignment, the tread wears faster. The same things happens with knees," Randall said. If you're concerned about bowlegs or knock-knees in your child, talk with your pediatrician.

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