Why Do Babies Have Bowlegs And Knock Knees?

Every parent wishes his or her baby grows up perfectly normal and healthy. It is scary when you notice your child’s legs looking bowed or knocked. Do not be too worried though. Bowlegs and knock-knees are a common occurrence in children’s development. Let’s get more into what they are about.

Bow Legs

Bowlegs occur when a child’s knees stay curved apart when the legs are upright. This is common with infants. Most babies have bowlegs when they are born, but it can only become more obvious when he/she starts walking. A majority of children, however, lose it when they grow older (by two or three years). Bowlegs are a normal part of growth and development, and not a result of a genetic disorder or vitamin D deficiency. 


This is the opposite of bowlegs. The knees usually touch while the ankles and feet stay apart. By around 3 years, a child can outgrow bowlegs and develop knock-knees. Like bowlegs, knock-knees are a normal part of lower extremities development and should straighten out by the time the child 7 or 8 years old. When this happens, you can expect that they will have the normal, but slight knock-knee in adults. 

When to See a Doctor

 It is advisable to visit your doctor if your child shows any of the following signs. 

  • Excessive angling of the knee either outward or inward
  • Pain on the knee angle
  • Unequal knee angles with a huge difference between the legs
  • One affected leg
  • Persistent bow legs after 3 years
  • Unusually short for a certain age

These signs could mean the possibility of an underlying illness such as rickets, osteomalacia and possibly obesity. 

How to Prevent Bow Legs or Knock Knees

This must sound exciting. But one thing that experts want you to know is that physiologic bowing is normal. It is a part of normal development and should not be completely prevented. Having said that, ensure that your baby gets:

  • Vitamin D and calcium – These are good for strengthening bone development. Most Kenyans believe that if you don’t let your baby bask in the sun in the morning and /evening, it is inevitable that they will develop bowlegs. In fact, some will accuse you of hiding your baby away from free sunlight should they spot curved or knocked-knees. While it is true that the sun helps the body produce vitamin D in large amounts, it is rare that a vitamin D deficiency can actually cause bowlegs. 
  • Controlled weight gain – It is also recommended that you help your baby maintain normal weight. Obese children have a higher chance of developing bowlegs. Proper knee alignment is vital for normal function and joint balance. There is even transfer of body weight through the middle of the joint in a properly balanced knee. 


#Please note that development differs from one child to another

# Content intended for educational purposes only, and should not be substituted for medical advice from your doctor.

Last reviewed January 2019

Sources: ucsfbenioffchildrens, pregnancybirthbaby, rch.org, healthychildren, childrenshospital, drgreene, babycenter

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