Weinstein Lovell and Winters Pediatric Orthopaedics 7e

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CHAPTER 30  |  The Child with a Limb Deficiency

for prosthetic use, and are the focus of this section. The child with an upper extremity amputation has an inherently different disability than the child with a lower extremity amputation. The importance of sensation in the hand, which is seen as the termi- nal “working end” of the entire upper extremity, cannot be over- emphasized. Without sensory feedback, the child with an upper extremity limb deficiency must look at the prosthetic hand to help it function. In addition, the child must think actively to control the terminal device of an upper extremity prosthesis. Both of these factors make upper extremity prostheses much less efficient and much more difficult to use than a lower extremity prosthesis. At best, any upper extremity prosthesis will be used more as an assisting limb rather than as a substitute capable of achieving bimanual function. Additionally, upper extremity amputations are very visi- ble. Unlike the child with a below-knee amputation who walks without a limp, has a prosthesis hidden under clothes, and can often match his or her peers in physical activity, the child with an upper extremity amputation is more easily seen as differ- ent. For both of these reasons, many patients with transverse upper extremity deficiencies will not be well served by pros- thetic prescription. If the prosthesis does not afford the child a functional gain or cosmetic benefit, he or she will be quick to reject it. The reasons for some children becoming good users of a prosthesis, whereas others with the same characteristics reject it, are not well understood. Although the age at initial pros- thetic fitting, as well as the parents’ acceptance and compliance are important, this is not the whole answer. The incredible ability of the young child to learn to use one hand assisted by the residual limb with minimal concession to activities that are assumed to require two hands must also be a significant factor. Quantification of successful upper extremity prosthetic use is very patient specific. The number of hours a prosthesis is used per day is not a good criterion. Many children will use the prosthesis for specific tasks (riding a bike) while preferring to remove it for others (swimming). Some children will wear and use it every day in school, but will wear it very little during the summer while playing. What the child can do with the prosthesis when asked and what he or she actually does with it in the course of a normal day can be very different. Although some children develop an amazing facility with the prosthesis in their everyday activities, many will demonstrate their skill with the prosthesis only in the medical setting, preferring to use the prosthesis much like their residual limb during daily activities. Standardized tests have been developed to measure spontaneous use versus voluntary control as it relates to age-appropriate activities. The University of New Brunswick test of myoelectric control is used by thera- pists to assess the child’s ability to use the prosthesis in a con- trolled situation. The Prosthetic Upper Extremity Functional Index is a self-reported measure of the child’s functional abili- ties during daily activities. The Unilateral Below Elbow test is an observed functional evaluation instrument that examines both completion of specific tasks and how the prosthesis was used in that task. James et al. found that, when evaluating uni- lateral below-elbow amputees with and without a prosthesis,

traditional scanogram radiographs can overestimate the amount of shortening. Scanograms should be obtained in the lateral position, which will account for any flexion deformity at the hip (or knee) in these patients. For patients where knee fusion and foot ablation is the treatment plan, an accurate prediction of femoral and tibial segment length at maturity will help the surgeon decide if the distal femoral and/or proximal tibial epiphysis and physis need to be removed at the same time. If one (or both) physes about the knee are removed at surgery, the physician should counsel the family that the residual limb will appear “too long” imme- diately after surgery, but that the normal limb will overgrow the residual one with subsequent growth. With regard to the hip flexion, abduction, and external rotation deformity seen in these patients, the authors experi- ence is that the deformity resolves after knee fusion and foot ablation with prosthetic use over several months. Therefore, when performing knee fusion, the tibia should be fused in line with the femur rather than in a flexed, adducted, internally rotated position to compensate for the proximal femoral seg- ment alignment. The authors do not have experience with concurrent soft-tissue release at the time of osteotomy (so- called “super-hip” procedure). Complications.  Progressive hip subluxation and frank dis- location can occur with femoral lengthening. Prevention of this complication is the best treatment. Careful evaluation of the hip should be undertaken prior to femoral lengthening, if it is to be performed. Hip dysplasia should be addressed prior to lengthening with appropriate acetabular reorientation or augmentation procedures. As mentioned previously, insufficient or recurrent rota- tion can occur after Van Nes rotationplasty. Treatment of this problem is with repeat tibial rotational osteotomy. Definition and Classification.  If upper extremity defi- ciencies were completely discussed like lower extremity deficien- cies, the list of topics covered in this section would be much larger. Longitudinal deficiencies in the upper extremity include radial and ulnar longitudinal deficiencies, as well as symbrachy- dactyly and cleft-hand deformity. Thumb hypoplasia or aplasia might also be listed. In contradistinction to the lower extremity, the shortening which results from these longitudinal deficiencies is rarely the primary clinical problem as it is in the lower extrem- ity. In reality, pediatric hand and upper extremity surgeons participate in multidisciplinary team clinics to care for these patients (much like pediatric orthopaedic surgeons participate in multidisciplinary team limb-­deficiency clinics), and surgical reconstructive treatment of these patients is best described in chapters dedicated to the care of these specific disorders. Often, it is the patient with terminal deficiencies of the upper extremity that are treated in limb-deficiency clinics, are often candidates Congenital Deficiencies of the Upper Extremity