Normally, lateral rotation of the tibia increases from approximately 5º at birth to approximately 15º at maturity; femoral anteversion decreases from approximately 40º at birth to approximately 15º at maturity.
Tibial torsion is inward twisting of the tibia (shinbone) and is the most common cause of intoeing. It is usually seen at age 2 years. Males and females are affected equally, and about two thirds of patients are affected bilaterally.[1]
In a study by Mullaji et al to determine tibial torsion norms, individuals in India were found to have less tibial torsion than Caucasians but about the same amount as the Japanese population.[2] The differences in normal tibial torsion values are expected to be caused by the different lifestyles and postures of the different populations, such as cross-legged sitting positions.[2, 3, 4, 5]
Whereas medial torsion improves with time, lateral torsion often worsens because the natural progression is toward increasing external torsion. The ability to compensate for tibial torsion depends on the amount of inversion and eversion present in the foot and on the amount of rotation possible at the hip. Internal torsion causes the foot to adduct, and the patient tries to compensate by everting the foot, externally rotating at the hip, or both. Similarly, persons with external tibial torsion invert at the foot and internally rotate at the hip.[6, 7, 8, 9, 10, 11, 12, 13]
The natural history of femoral torsion is to resolve by the time the patient is aged 8-9 years. Beyond this age, all remodeling will have occurred, and any further correction is due to a conscious modification of posture.
Normal femoral anteversion is 40º in the newborn and decreases to 10º by the age of 8 years. The acetabulum is angled forward 15º. Femoral anteversion does not increase the risk of arthritis of the hip. Spontaneous improvement in the anatomic position can occur up to the age of 8 years, and further correction can be achieved by improving the gait through conscious effort until adolescence.
NextThe patient's history should consist of details of the age at onset, severity, disability, milestones, and family history.
In children younger than 18 months, metatarsus adductus is the most common condition that causes intoeing. Between the ages of 18 months and 3 years, tibial torsion is the most common condition. In children older than 3 years, femoral torsion is the most common diagnosis.
The diagnosis is based on clinical findings, and other investigations generally are not required. Examination must include tests to exclude hip dysplasia, hip and ankle ranges of motion, and knee varus or valgus, which can cause apparent errors in examination. Imaging studies may be helpful. However, not every child who undergoes an evaluation because of torsional issues requires any or all imaging tests.
Parents are generally more concerned about intoeing than the children are. Severe intoeing can cause the child to trip or run awkwardly, and it can interfere with their participation in sports. Excessive wear is seen along the lateral border of the shoe, mainly in the front half, because the child uses this as the presenting border of the foot on the heel- or foot-strike.
A rotational profile consists of the following[14, 15, 16, 8, 11, 12] :
The FPA is the angular difference between the axis of the foot and the line of progression. Normal FPA is 10-15° of external rotation. By convention, external rotation values are positive, and internal rotation values are negative. Degrees of intoeing are as follows:
Tibial version or torsion is the degree of rotation of the tibia along its long axis from the knee to the ankle. It is measured with the patient prone with his or her knees flexed to 90°. It is assessed by using two measures, the TFA and the transmalleolar angle.
The TFA is measured with the patient prone and the knees flexed to 90°, with the examiner looking at the feet from above. It is the angle between the line of axis of the thigh and the line along axis of foot. A normal TFA is 10-15° of external rotation. By convention, external rotation values are positive, and internal rotation values are negative.
The transmalleolar axis is the axis of the line joining the two malleoli. Because the lateral malleolus is normally posterior to the medial malleolus, the transmalleolar axis is externally rotated by 15-20°, as measured with reference to the coronal plane axis. A transmalleolar axis that is externally rotated more than 20° signifies external tibial torsion, and a transmalleolar axis externally rotated less than 10° signifies internal tibial torsion.
Femoral anteversion is the axial angle between the plane of the neck of the femur and the femoral condyles. It can be clinically deduced by measuring hip rotation. Normal range of external rotation is 45-70°, and internal rotation is 10-45°. As femoral anteversion increases, internal rotation increases and external rotation decreases. These children can have as much as 90° of internal rotation and 0° of external rotation. They sit in the W position with their legs turned out (a position not attainable by normal adults), but they cannot sit cross-legged.
The shape of the foot is best assessed with the patient standing and examined from the back, or else the patient can be prone and the feet assessed by looking at the soles. Metatarsus adductus (or uncommonly, abductus) can be seen.
Osteotomy is indicated if the deformity is more than three standard deviations (SDs) from the mean (less than –10° or more than +35°).[17, 18, 19, 20]
Osteotomy correction is indicated if the deformity is more than three SDs from the mean and is a cosmetic or functional problem (ie, internal rotation of 85°, external rotation of less than 10°).
No absolute contraindications exist for treatment of tibial torsion, provided that the indications for treatment are satisfied. Relative contraindications include borderline neurovascular status (especially if acute correction is contemplated), poor skin condition, and poor surgical risk overall.
Lack of inversion is another relative contraindication to the correction of long-standing internal tibial torsion. This condition affects the patient's ability to position the foot down after external rotation correction. Patients with long-standing internal torsion tend to compensate by everting the foot. Excessive hip external rotation coupled with a lack of internal rotation, which is suggestive of retroverted hips, can be a good counter to internal tibial torsion. Tibial correction may lead to excessively externally rotated feet.
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