CHAPTER 30
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The Child with a Limb Deficiency
1531
this responsibility. The professionals caring for the family must
provide the necessary education and framework in which the
parents can make these decisions.
Family involvement is an essential part of the treatment
program (31). The child has a condition he or she will adapt
to, rather than a disease that can be cured. Hence, the condi-
tion should not be “medicalized,” but rather treated within the
context of family, home, school, and play, not through clinic
visits.
General Treatment Pearls and
Pitfalls
Predicting Growth.
It has been observed that the per-
centage of shortening in a congenital limb deficiency remains
relatively constant. This is sometimes referred to as the “rule
of proportionality.” This principle has been established
for congenital short femur (32–34) and fibular hemimelia
(35, 36). Clinical experience indicates this to be true for the
tibial hemimelias also. It follows from the rule of proportion-
ality that differences in limb length will increase as the child
grows. Therefore, in discussing centimeters of shortening
and planning treatment, it is important to calculate what the
discrepancy will be at maturity rather than focus on what it
measures currently. This can be roughly estimated by knowing
only the percentile height of the child. With this information,
the length of the femoral and tibial segments of the normal
limb can be estimated from the Green and Anderson growth
charts (37) (Tables 30.2 and 30.3). Then, knowing the length
of the normal segments and the percentage by which the
affected segments are short, the length of the affected segments
at maturity can be estimated.
Although this method of calculating the eventual discrep-
ancy at maturity is clinically valid, the clinician should be aware
of the effect that surgical procedures could have on the growth
of the limb. Following amputation, the epiphysis of the bone
may not grow at the normal rate. Christi et al. (38) showed
that in 20 below-knee (BK) amputations in children, only
three tibias grew at the expected rate. The congenital group of
tibias grew to 36% of what would have been expected, and the
acquired group grew to 53% of the expected level. This may be
due to the lack of stress across the growth plate, the decreased
blood flow to the bone, or the result of the congenital insult
that produced the limb deficiency.
Timing of Amputation.
The timing of an amputation in
a congenital limb-deficient child is tied into the developmental
age of the child. In general, amputations for lower extremity
congenital deficiency are elective and designed to aid prosthetic
fitting. As such, amputation is best performed a few months
before the child is developmentally ready to walk (usually
when the child is pulling to stand). This gives enough time for
the residual limb swelling to subside and for fabrication of the
prosthesis. This will allow the child after surgical recovery to
maintain a normal developmental sequence. In rare instances,
a deformed extremity can interfere with crawling, and amputa-
tion may be performed earlier. However, prosthetic fitting in
such children should wait until it will be of some functional
value. In other cases (e.g., PFFD), amputation may be done
at a slightly later age (and
after
prosthetic fitting because of
technical reasons).
Although it is poorly documented, there is the impression
among both parents and surgeons that with early amputation
the child does not experience the body image loss that accom-
panies amputation at a later stage. Also important is that as a
general rule, the earlier the amputation, the better the adapta-
tion of the child’s neurologic plasticity to the alteration. No
upper age limit has been identified, although most amputa-
tions should be performed before school age, if possible.
Overgrowth.
Bony terminal overgrowth at the end of the
residual limb is the most common problem in juvenile ampu-
tees. Its occurrence is reported to be between 20% and 50%
and depends on the cause of the amputation, the age of the
patient at the time of amputation, the bone involved, and the
location within the bone involved (39–41). It occurs most
commonly following traumatic amputation or elective ampu-
tation through a bone. It is less often seen in congenital ampu-
tations because of amniotic band syndrome but not in those
due to failure of limb development. It is not seen in amputa-
tions through joints (42). Overgrowth occurs most often in
below-knee amputations, with the problem being present in
the fibula more often than in the tibia, and in transhumeral
amputations. The incidence of overgrowth is less common
if the primary amputation is performed before the age of
12 years. Recurrence is common and is felt by some to be more
common during periods of rapid growth when bone turnover
is high (e.g., adolescence).
Contraction of the soft tissue and physeal-mediated
growth of the bone, pushing it through the skin, were
originally thought to be responsible for bone overgrowth.
Aitken disproved these theories when he demonstrated by
implanting metallic markers that the overgrowth took place
distal to the end of the bone (39, 43). The new bone is peri-
osteal and endosteal appositional bone. Overgrowth results
from the typical process of wound contracture as has been
demonstrated by Speer (44). Following a through-bone
amputation, the periosteum continues to grow. As it grows
over the end of the bone, it grows over the open medullary
canal, where it contracts and is drawn into the canal from
which it can continue to grow, producing the overgrowth at
the end of the bone.
Patients with terminal overgrowth present clinically with
pain on weight-bearing or prosthetic use. An antalgic gait
with decreased stance time may be noticed. Decreased range
of motion, to limit pulling of the skin at the end of the limb,
is an additional symptom. Clinically, the patient presents with
tenderness and pain at the end of the residual limb. There
may be inflammation, bursal formation, or the bone end may
be protruding through the skin. Commonly, the bony spike
can be palpated within a small, tender bursa (Fig. 30-2A–C).
