Leg

Bow Legs and Knock-Knees

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Although infants are born with bowlegs, where the knees appear to "bow" out from the body, the knees tend to straighten out between 18 and 24 months of age. In turn, when most children begin to walk -- at around 12 months of age -- they appear to be bow-legged.

Knock-knees, on the other hand, are when the knees appear to bend toward each other. If a child is knock-kneed, it will be most evident when he or she is around 3 years of age, and will then gradually become less pronounced. By age 7, they will have attained the normal adult amount of slight knock-knee -- 5 to 9 degrees -- which they will maintain throughout their life.

Although you may be concerned about the shape of your child's legs, a slight degree of bowing or knocking is normal. That said, if your child exhibits any of the following, it is probably a good idea for a pediatric orthopedist to take a look:

• Excessive knee angle either inward or outward.

• Unequal knee angles. While slight variation from one side of the body to the other is normal, a large difference between one leg and the other should be investigated.

• Pain or other complaint connected to the knee angle.

• Bowlegs after 3 years of age. This is when children have the greatest amount of knock-knee alignment and, therefore, bowlegs would be abnormal at this time.

• Knock-knees at an angle greater than 15 degrees.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated May 8, 2007