Weinstein Lovell and Winters Pediatric Orthopaedics 7e

1578

CHAPTER 30  |  The Child with a Limb Deficiency

the limb as possible. This often results in a less functional level of amputation than one that is more proximal. The most obvi- ous example is preservation of the talus and calcaneus, which the parents and child may see as saving at least part of the foot, whereas the result may be a worse gait, worse cosmesis, and more prosthetic problems than with a Syme amputation. In the child, it is usually advisable to preserve as much length as possible in amputations of the long bones. This is especially true in the femur, in which 70% of the growth of the bone occurs from the distal physis. A 5-year-old child with a midthigh amputation will have less than ideal length as an adult. In the lower leg, however, little is lost, so long as an ade- quate portion of proximal tibia, in which most of the growth occurs, is preserved, and in fact, shortening the bone to achieve good soft-tissue coverage may be the best course. The adult dictum, that skin grafts do not make suitable coverage for a residual limb that will bear weight in a prosthesis, is not applicable to children, especially very young ones. In chil- dren, skin grafts do make good coverage as long as they are not adherent to the bone. Split-thickness skin grafts are frequently needed to preserve length in meningococcemia, burns, and some cases of trauma. In older children with traumatic amputa- tions, free vascularized flaps can provide excellent coverage. Where possible, disarticulations are preferred over through- bone amputations because they will prevent the problem of bony overgrowth. It is not necessary, or perhaps even advisable, to remove the cartilage from the bone end. Tapering of the bone ends, at the distal tibia, for example, is not necessary unless the child is approaching adulthood. The bony prominences will not develop to adult proportions and therefore do not present a prosthetic fitting problem. If a young child has a through-bone amputation, it may be possible to salvage a portion of bone and cartilage from the amputated part for capping the bone. This is similar to performing a Marquardt procedure and has the potential to substantially reduce problems of overgrowth. It is important not to forget the child during the acute phase of the amputation. Often the surgeon expends a great amount of energy dealing with the parents’ emotions and can easily forget that the child also needs emotional as well as physical attention. In many circumstances, the amputation will be elective. Such is the case with children who have posttraumatic injuries and are electing surgical modification for better function and prosthetic fitting. Children with neurofibromatosis, Klippel- Trenaunay-Weber syndrome, and malignant tumors not suit- able for limb salvage also are in this category. In many cases, the need is obvious, and the child and parents have accepted their decision after careful consideration. In the case of tumors, however, it is usually not so easy, and generally there is not complete acceptance of what is in fact a life-saving procedure. In all cases, the more prepara- tion by the medical professionals and opportunities for the parents and patient to talk and see other patients, the better. It needs to be emphasized that the challenge to be overcome with ­treatment is to live, and that the surgery is necessary for that. The options revolve around the functional and cosmetic aspects of the different procedures.

Patients with transcarpal amputations often have radio- carpal motion with limited pinch function. It is difficult to improve function in these children, either with prosthetic fit- ting or with surgery. In the child with four-extremity limb deficiency, it is best to hold off on fitting upper extremity prostheses until the child has been fit with lower extremity prostheses and begun walking. Complications.  Complications of the Krukenberg opera- tion have been previously mentioned and include radial head subluxation progressing to dislocation as well as ­inadequate pincer power. With regard to lengthening residual transverse forearm residual limbs, elbow subluxation and/or contracture are possible complications, along with the usual complications that go along with limb lengthening of any sort. Acquired Deficiencies Causes.  Children may undergo an amputation for a vari- ety of reasons. Although there are no good statistics, trauma is the major cause of amputation in childhood (214). In this group, power lawnmowers lead the list of causes, and most commonly, it is a young child riding on the lap of a family member. Motor vehicle accidents (particularly all-terrain vehi- cles), farm injuries, and gunshot wounds follow in that order (215). In war-torn countries, landmines may be the leading cause of amputation. Because amputation of the digits is most often caused by machinery, upper extremity amputations are more common than those of the lower extremity. Boys are affected about twice as often as girls. Tumors, vascular occlusion caused by meningitis or vascu- lar catheterization, and burns are additional causes, and each has its own unique set of circumstances. Indeed, the differences in acquired amputation defy classification. Some are semielec- tive and allow for some preparation of the patient and the parents, whereas traumatic amputations do not. It is ­possible, however, to discuss the general principles that are applicable to acquired amputations in children. Principles.  When the surgeon is faced with an acutely mangled extremity, it can be difficult to decide on amputa- tion versus limb salvage. Treatment principles in adults are not easily transferred to children. Most often, multiple physicians should discuss the case to make the best assessment, while always remembering the tremendous healing and adaptive capacity of the child, compared with the adult. When dealing with lawnmower injuries to the foot, it is often wise to attempt limb salvage at the first surgery. However, for more proximal lawnmower injuries that will require vascu- lar and nerve repair, along with bone reconstruction and free tissue transfer, the decision needs to be made more realistically. The more energy expended in saving the limb, the higher the parents’ expectations of the result. The surgeon will rarely have options regarding the level of amputation in trauma. This usually dictates saving as much of