Weinstein Lovell and Winters Pediatric Orthopaedics 7e

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CHAPTER 30  |  The Child with a Limb Deficiency

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.

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).

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,