Medical Therapy
Treatment with orthoses generally is ineffective. The condition has a benign natural history. Because most cases resolve spontaneously, observation with yearly review is generally all that is needed. True metatarsus adductus is an intrauterine positional deformity that resolves in 90% of cases by the age of 4 years. If no improvement is seen, cast correction by using a long leg cast can be attempted. A weekly cast change for 4-5 weeks is generally needed.
Surgical Therapy
Indications and contraindications
Osteotomy for tibial torsion is indicated if the deformity is more than three standard deviations (SDs) from the mean (less than –10º or more than +35º). [30, 31, 32, 33, 34] Osteotomies (supramalleolar osteotomy) can be performed at any level. [35, 36]
Osteotomy for femoral torsion is indicated if the deformity is more than three SDs from the mean and is a cosmetic or functional problem (ie, internal rotation of 85º, external rotation of < 10º). Osteotomy can be performed at any level: subtrochanteric, diaphyseal, or distal. Distal osteotomies are easier to fix and are associated with less blood loss and quicker healing.
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 for 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.
Operative details
The authors prefer supramalleolar osteotomies because they are easier to perform. Attention is directed toward making the bone cuts perpendicular to the long axis so as to avoid building an angular deformity into the rotational correction. A fibular osteotomy should be created to allow stress-free tibial rotation. This also preserves the distal tibiofibular articulation. The osteotomy is made 2-3 cm proximal to the distal tibial physis.
Proximal tibial osteotomies must be performed distal to the tibial tuberosity to prevent rotation of the patellar tendon insertion; if this is rotated externally, it can predispose the patient to patellar maltracking in the trochlea and lateral patellar dislocation.
In younger children, osteotomies can be fixed by using Kirschner wires (K-wires) or small fragment plates. In older children, intramedullary devices, plates, or external fixation can be used. Ilizarov devices can be used with rotational boxes, but the Taylor spatial frame is best suited for rotational correction.
A size mismatch and some translation occur between the proximal and distal segments after significant rotational correction.
The metaphysis is the best place to perform an osteotomy in terms of the speed of healing. Proximal tibial metaphyseal derotation osteotomies alter the patellar tracking and the patellofemoral joint mechanics, and they are not preferred. Also, osteotomies can be performed in the distal tibia and fibula, which can be derotated as a single functional piece, thus avoiding alteration of the ankle mechanics.
Long-Term Monitoring
The lower extremity is immobilized in a nonweightbearing short leg cast for 4-6 weeks. The cast merely augments the initial stability achieved by using internal fixation. Once the cast is removed at 4-6 weeks after surgery, the healing is generally solid enough to allow removal of the K-wires. Immediate unprotected weightbearing is allowed.
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Lateral radiograph of 1-year-old child with posteromedial tibial bowing.
