Orthopedics - Oleksa A.P. 2006

Congenital and acquired deformities of the lower limb
Congenital deformities of the lower leg
Congenital absence of the tibia

Out of 24 children with tibial aplasia, Isayeva 1.1 et al. (1986) established the inheritance of similar deformities in two cases.

Congenital absence of the Tibia is a much more severe defect than fibular aplasia because the tibia is the primary weight-bearing bone of the body, articulating with the Femur at the knee joint.

Tibial aplasia is extremely rare and can also be complete or partial. Complete absence of the tibia poses a significant Treatment challenge, as there is essentially no Patella or normal knee joint. Instead of a joint, there is an ovoid femoral condyle, and the Fibula migrates proximally, develops a varus deformity, and assumes the function of the tibia (Krys-Puhach A.P., Syvak M.F., 2001).

As a result of the missing bone, a corresponding developmental anomaly of the lower leg Muscles occurs; they undergo intrauterine hypoplasia because they lack normal attachment points. The quadriceps femoris and the "semi" group also fail to develop properly, attaching instead to a rudimentary capsule and a fibrous band at the site of the absent tibia.

The FOOT is deformed in a Clubfoot-like manner (equinus, varus, forefoot adduction, and inward dislocation of the foot).

Such severe changes do not occur in cases of partial aplasia with normally developed proximal and distal ends of the tibia.

Absence of the tibia is easy to diagnose clinically within just a few days of birth. In all cases, the lower leg is shorter, with a pronounced varus deformity that impairs walking in 2- to 3-year-old children. The foot is supinated, and the lateral malleolus (malleolus lateralis) protrudes and is clearly palpable. Palpation also reveals partial or complete absence of the bone, with severely restricted movement in the rudimentary knee area or the presence of a flexion contracture of the shortened and deformed lower leg. The Diagnosis is confirmed radiographically (Fig. 178).

Treatment of this congenital lower leg defect must begin immediately after birth, while the Tissues are still pliable, allowing Conservative Methods to correct deformities and prevent their progression as the child grows. To achieve this, lower leg tissue massage and physical therapy are performed, and corrective plaster or plastic splints are initially prescribed (at 1 to 2 months of age), followed by orthopedic braces and footwear once the child begins to walk.

However, improving the weight-bearing capacity of the limb and correcting its axis can only be achieved surgically. With modern Anesthetic Management, surgery can be performed at 3 to 4 years of age, or even earlier. Historically, the weight-bearing capacity of the limb was improved by fusing (ankylosing) the femur to the fibula.

If the tibia is absent, it is replaced with the fibula using the Putti Procedure.

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Fig. 178. Congenital absence of the tibia, compensatorily hypertrophied fibula, and adduction subluxation of the foot.

Under general anesthesia, the tissues, including the Joint Capsule, are incised via an anterolateral approach. The HEAD of the fibula is transposed into the intercondylar fossa of the femur and, to secure it in place, is fixed with sutures to the capsule or transosseously with a Kirschner or Ilizarov wire (Fig. 179). The patellar ligament (lig. patellae proprium) is isolated and sutured to the fibula. The distal end of the fibula is secured in the talus with the foot in an equinus position. As the child grows and bears weight on the leg, the proximal end of the fibula widens, and the bone hypertrophies, becoming capable of bearing body weight. In the second stage of the surgery, following an osteotomy, the axis of the fibula is aligned and, if necessary, lengthened using the Ilizarov method. If the distraction regenerate fails to compensate for the shortening, a femoral shortening procedure can be performed on the healthy leg.

Krys-Puhach A.P. and Syvak M.F. (2001) identify four stages of treatment for these children.

Fig. 179. Radiograph of the fibula transposed under the femur with fixation of both segments using a thick wire.

In The First stage, conservative treatment is aimed at resolving contractures in the knee and ankle joints, strengthening the muscles, and improving Blood Circulation in the lower leg.

In the Second Stage, for severe contractures, soft tissue surgeries in the ankle joint area are performed starting from six months of age: release of the tibial fibrous band, lengthening of the tendons that hinder deformity correction, and capsulotomy with centralization of the foot. The foot is fixed with a rod or Kirschner wires.

In cases of severe knee joint contracture, the Third Stage is initiated, which involves applying an Ilizarov apparatus with a hinge at the knee joint to gradually correct the contracture, maintaining a 2-3 cm diastasis between the femur and the fibula.

The Fourth Stage consists of reconstructing the knee joint. A socket is created in the lateral femoral condyle, and the head of the fibula is rounded and inserted into this socket. Both collateral ligaments are then reconstructed from soft tissues, and the quadriceps tendon is transferred to the anterior surface of the fibula. The leg is immobilized in a hip spica cast for 1-1.5 months, followed by Therapeutic Exercises and physiotherapy.

Such surgeries are technically demanding, requiring exceptional surgical skill and prolonged, comprehensive rehabilitation. A successful outcome is achieved when the fibula becomes a reliable weight-bearing Structure and the knee range of motion is within 40-60°.