Knock Knee Deformity

Angular deformities of the knee are common during childhood and usually are variations in the normal growth pattern. Angular deformity of the knee is a part of normal growth and development during early childhood. Physiologic angular deformities vary with age as:

  • During first year: Lateral bowing of tibia
  • During second year: Bow legs (knees and tibia)
  • Between 3-4 years: Knock Knees

The condition usually becomes more evident when the child is 2 to 3 years old and normally corrects itself by the time a child is 7 or 8 years old. However, if the condition is not corrected it could be a sign of an underlying disease that requires treatment.

A perfectly aligned knee has its load-bearing axis on a line that runs through the hip, knee and ankle. Based on the inward/ outward inclination of the head of tibia/fibula; knee angular deformities are classified as:

  • Genu valgum (knock-kneed): Head of tibia/fibula (not the joint itself), is inclined away from the midline of the body
  • Genu varum (bow-legged): Head of tibia/ fibula is inclined toward the midline of the body

Genu Varum (bowed legs)

Bowed legs are very common in toddlers. If a child has bowlegs, one or both legs curve outwards. When your child stands there is a distinct space between the lower legs and knees. Bowed legs are rarely seen in adolescents. In most of the cases, children with bowed legs are significantly overweight.

Genu valgum (knock-kneed)

Knock knees is a condition in which the legs curve inward at the knees. When a child stands, the knees appear to bend toward each other and the ankles are spread apart.

Knock knees most often develop as a part of normal growth. In some cases, especially if the child is 6 years of age or older, knock-knees may occur as a result of other medical problems such as injury of the shin bone, osteomyelitis (bone infection), overweight, and rickets.

Diagnosis

The diagnosis of knock knees is made through a physical examination. In addition, X-rays may be taken if a child is older than 2 ½ years and has symmetrical legs.

Treatment for Knock-knees

Most children with knock knees do not require any treatment, but if the condition persists after age 7, then a night brace attached to an orthopedic shoe may be recommended. If the separation between the ankles is severe, surgery may be an option.