Genu varum and valgum is physiologic (normal) at certain points in a child's development.

This graph demonstrates the normal transition from genu varum (birth to age 2) to excess genu valgum (peaks at age 3) and eventual normalization to an adult pattern (5 to 7 degrees valgum) - from Salenius P, Vankka E: The development of the tibiofemoral angle in children. JBJS 1975;57:259 (Copyright Journal of Bone and Joint Surgery; used with permission)

Infants and children up to approximately 2 years of age frequently exhibit genu varum. Internal tibial torsion often co-exists with genu varum and may to accentuate the 'bow-legged' appearance. Children with other abnormalities such as short stature should be investigated with x-rays to determine if this is part of a generalized skeletal abnormality (or skeletal dysplasia). Radiographs are otherwise deferred unless the deformity is extreme or progressive. Non-physiologic genu varum may be the result of abnormalities of bone mineralization (rickets), skeletal dysplasia or "Blount's disease", a condition of unknown etiology where the medial tibial growth plate becomes disturbed and does not grow normally. Between the ages of 2 and 3 years, most children develop genu valgum. This may exceed the normal 5-7 degrees seen in adults and usually peaks at about 36 months of age.

Deformity can be quantified and followed in both cases by clinical measurements of the femoral tibial axis and/or by the distance between the medial femoral condyles or medial malleoli when standing. In cases of physiological genu valgum or varum, reassurance is all that is needed. If the diagnosis is uncertain, then it is helpful to follow the patient clinically over time to determine whether there is progression or resolution of deformity.

3-year old boy with physiologic genu valgum. This requires no treatment.

Indications for x-rays are similar to those for genu varum. Deformity can be quantified and followed in both cases by clinical measurements of the femoral tibial axis and/or by the distance between the medial femoral condyles or medial malleoli when standing. In cases of physiological genu valgum or varum, reassurance is all that is needed. If the diagnosis is uncertain, then it is helpful to follow the patient clinically over time to determine whether there is progression or resolution of deformity.