Tibial Torsion Treatment & Management


Background

Tibial torsion is inward twisting of the tibia (shinbone) and is the most common cause of in-toeing. It is usually seen at age 2 years. Males and females are affected equally, and about two thirds of patients are affected bilaterally. [12]

Normally, lateral rotation of the tibia increases from approximately 5º at birth to approximately 15º at maturity. 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. [345678910]

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.

Epidemiology

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. [11 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. [11121314]

Prognosis

Drexler et al conducted a study to evaluate the clinical and radiographic outcomes of 12 patients (15 knees) undergoing tibial derotation osteotomy and tibial tuberosity transfer for recurrent patella subluxation associated with excessive external tibial torsion. [15 Clinical evaluation was carried out using preoperative and postoperative Knee Society Score, Kujala Patellofemoral score, the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire, the Short Form (SF)-12, and a visual analogue score (VAS) pain scale.

Significant improvement was achieved on all measures. [15 Two patients had a nonunion of the tibial osteotomy site, one patient required bone grafting, and another patient required revision to total knee arthroplasty. The investigators concluded that for patients with recurrent patella subluxation secondary to excessive external tibial torsion, satisfactory outcomes in terms of pain relief and improved function can be achieved through tibial derotation osteotomy and tibial tuberosity transfer.

In a study of surgical treatment of 44 children with torsional malalignment of the tibia, Erschbamer et al performed 71 percutaneous derotational osteotomies of the distal tibia. followed by application of an external fixator. [16 On postoperative radiographs, accurate tibial derotation and pin placement were noted in all patients. In nine patients, superficial pin-tract infections developed but resolved with administration of antibiotics; in two. fractures developed after the external fixator was removed but healed in a plaster cast. The investigators found this approach to be safe, effective, and well tolerated.


History

The 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.

Physical Examination

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 in-toeing than the children are. Severe in-toeing can cause the child to trip or run awkwardly, and it can interfere with 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 [171819589:

  • Foot progression angle (FPA) [20]
  • Tibial version or torsion - Thigh-foot angle (TFA), transmalleolar angle
  • Femoral anteversion (hip rotation)
  • Shape of the foot

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 in-toeing are as follows:

  • Mild is –5 to –10°
  • Moderate is –10 to –15°
  • Severe is more than –15°

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.


Imaging Studies

Plain radiographs of the hip are obtained to rule out hip dysplasia. Erect-leg full-length radiographs are important for measuring leg lengths, and anteroposterior (AP) and lateral views are important for measuring the distal femoral and proximal and distal tibial angles. (See the image below.)

Lateral radiograph of 1-year-old child with posterLateral radiograph of 1-year-old child with posteromedial tibial bowing.

Computed tomography (CT) is the criterion standard. [21Axial sections should be obtained through the hips and femoral necks, the femoral transcondylar axis, and the transmalleolar axis. [22Fluoroscopy and biplane radiography are alternatives.

Rosskopf et al conducted a study to evaluate the interchangeability and reliability of femoral and tibial torsion measurements in children using three-dimensional (3D) models based on biplanar radiography in comparison with CT measurements. [23They found that femoral and tibial torsion measurements in children using 3D models based on biplanar radiography were comparable with results with CT and that torsion measurements in children on biplanar radiography were as reliable as those on CT images, despite skeletal immaturity.

In children and adolescents, some prefer magnetic resonance imaging (MRI) so as to avoid exposing the patient to radiation. [24Basaran et al assessed the use of MRI to measure tibial torsion in 34 limbs in 17 children (mean age, 7.3 years; range, 3-12 years) and concluded that the most useful parameters for this purpose were the anterior talus angle and the posterior malleolar angle. [25]

Rosskopf et al also compared tibial torsion measurements in children obtained  by means of MRI with those from 3D models based on low-dose biplanar radiography. [26​ They found that tibial torsion measurements differed between the two modalities but that these differences were comparable to measurement variations between CT and BPR. 



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 all that is generally 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). [2728293031Osteotomies (supramalleolar osteotomy) can be performed at any level. [3233]

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.


Tibial Torsion Treatment & Management



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