Knock Knees (Genu Valgum)

Genu valgum refers to knees that turn inward, commonly referred to as “knock knees.” This is a normal part of leg alignment in childhood. Children between 2 and 4 years old have the greatest degree of genu valgum. This slowly straightens out with growth until 7 to 8 years of age without the need for treatment.

Genu valgum usually does not require treatment, as most children will correct their leg alignment with typical growth. In the rare instances when genu valgum does not improve with growth or gradually continues to worsen in later childhood, the only effective treatment is a surgery called a hemiepiphysiodesis, also called a guided growth surgery. During this procedure, a small metal plate is placed across the growth plate (typically of the femur just above the knee) to slow growth on the inside of the knee and allow the outer portion of the leg to grow and slowly straighten out with time.

This surgery requires a few years of remaining growth to achieve the desired result, but if done too soon can cause a child to overcorrect and develop genu varum (bow legs). If there is insufficient growth remaining, a guided growth surgery would not be helpful and the only way to surgically correct the leg alignment is to do a surgery called an osteotomy where a wedge of bone is removed to fix the alignment.

It’s important to note that families will frequently notice that their child’s feet appear flat when they are knock kneed. This is due to the ankles and feet rolling inward and flattening the arches to account for inward alignment at the knees. The arches typically remain present when not putting weight through the feet and having knock knees does not result in long-term flattening of the feet, as the feet do not appear as flat once the knee alignment improves.