External tibial torsion occurs normally with growth: from 0° at birth to 20° by adulthood. External torsion is rarely a problem.
Internal tibial torsion is common at birth, but it typically resolves with growth. However, an excessive degree of torsion may indicate a neuromuscular problem. Torsion also occurs with Blount disease. Persistent, excessive torsion can lead to toeing-in and bowlegs.
To evaluate for tibial torsion, the angle between the axis of the foot and the axis of the thigh is measured with the child prone and the knees flexed to 90°. Typically the foot axis is 10° lateral relative to the thigh axis. This angle can also be measured by seating the child and drawing an imaginary line connecting the lateral and medial malleoli.
In most children, the tibia returns to a normal position without treatment around 5 to 6 years of age. Children who have a severe case of tibial torsion may need to wear orthotics, a cast, or leg braces.