CHAPTER 30
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The Child with a Limb Deficiency
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FIGURE 30-20.
A,B
: AP and lateral clinical photos of a patient with fibular absence who had a Syme amputation with heel
pad migration. The heel pad has migrated posteriorly, and the patient has a painful discolored area over the distal tibia from
weight bearing.
Lengthening.
One complication specific to these patients is
subluxation of the knee or ankle during lengthening. At the
knee, posterior subluxation of the tibia and development of a
progressive knee-flexion contracture can be seen with femoral
lengthening. This happens because there is a high incidence of
cruciate ligament dysplasia in these patients. Prevention of this
problem before it occurs is best, which can be accomplished
by using a hinged knee orthosis that can be locked in exten-
sion, performing an extra-articular anterior cruciate ligament
reconstruction, and/or by spanning the knee joint with the
external fixator with a hinge placed at the knee joint during
lengthening.
Progressive subluxation can also occur at the ankle joint
with lengthening of the tibia. These patients often have abnor-
mal lateral supporting structures, including the lateral malleo-
lus and lateral stabilizing ankle ligaments. Inclusion of the foot
in the fixator frame is one treatment which has some success
in preventing the complication (122). If the complication
develops, subsequent ankle soft-tissue stabilization, distal tibia
osteotomy, or fusion may be necessary (123).
Tibial Deficiency
Definition and Classification.
The most common clas-
sification system of tibial deficiencies is the Jones classification,
which is a modification of the earlier Kalamchi and Dawe clas-
sification (99). The Jones classification is based on the radio-
graphic appearance of the limb within the first year of life. In
type 1 tibial deficiencies, ossification of the tibia is absent. In
type Ia, there is hypoplasia of the femoral epiphysis, implying
a complete lack of any tibial anlage articulating with the distal
femur (Fig. 30-21). In these children, the extensor mechanism
is usually severely deficient or absent. In rare cases, bifurca-
tion of the distal femur can be an associated finding in these
patients. In type 1b tibial deficiencies, the femoral condyles are
more developed, implying there is a cartilaginous tibial anlage
present that articulates with the distal femur (Fig. 30-22). This
anlage eventually ossifies with further growth usually between
2 and 4 years of age. These patients often have a functioning
extensor mechanism.
Jones type 2 tibial deficiency has a proximal tibia with
absent ossification of the distal tibia. This group is the same
