Medically referred to as Genu Valgum, knock knees are common in children between the ages of three and seven. When a child with knock knees stands with their knees together, the feet and ankles stay apart. The legs will usually gradually straighten as the child grows, although mild knock knees can last into adulthood.
If the severity of knock-knees increases or does not improve by age 10, then further evaluation and testing may be warranted.