Chapter 31 - Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation Principles
Introduction to the Child Amputee
John R. Fisk, M.D.
This Atlas is about prosthetics, but the needs of the limb-deficient child are not merely those of replacement parts. Even in the discussion of surgical principles, there is a different set of rules to follow when working with children. The disabled child missing all or part of one or more limbs is a growing, developing, and learning individual. Equally important, the child has parents and siblings who are growing and learning along with them. Thus, when we work with the limb-deficient child, we have many different considerations beyond those involved with treating adults. The chapters that follow address many of these unique concerns.
The child is not just a small adult. In addition to the obvious differences brought about by growth, children react differently to disabilities than do adults. There are two major categories of pediatric patients with limb deficiencies. Those who were born with them, i.e., congenital deficiencies, and those who acquired them after birth, i.e., amputations. In the first instance, the child has no sense of loss and nothing new to get adjusted to. Anything of a prosthetic nature is an aid, not a replacement, and if it is not truly an aid, the child will reject it. Those who lose a limb due to trauma or disease, unless their amputation occurred when they were very young, will have a profound sense of loss and undergo a period of readjustment. How well they manage this change greatly affects their acceptance of replacement prosthetic limbs.
The motivations of the two groups are different. In the first instance, congenitally limb-deficient children will try to do whatever other kids do. We find that their only limitations are those placed upon them by adults. Left to their own devices, they are very adaptable. Acquired amputees, on the other hand, want to be as they were prior to the amputation. They will mourn the loss of their limb; they will be angry and resentful. Their motivation will be greatly influenced by their ability to resolve this inner turmoil.
The two groups of children have parents and relatives involved in their care. Whether of congenital or acquired etiology, their child's limb deficiency is a great source of guilt for them. They will proceed through the universal grief response. We are greatly indebted to Kubler-Ross for her work in helping to clarify the stages of the grief process. Initially there will be shock, and then denial and anger. There will be a great sense of disappointment because of lost dreams and expectations not able to be met by their disabled child. With resolution and acceptance, new, more realistic expectations will be set so that in the end, if all goes well, the child will receive the support and nurturing that are doubly necessary to assist growth with the disability. Health care professionals involved with a family working through these stages must learn to recognize the changes as they occur and be prepared to alter their approach accordingly.
Rev. Harold Wilke, born completely without arms and well known for his work with the disabled, once said that the most important action that his parents took while he was growing up was to decide to have another child. That gesture showed him that they loved him for who he was sufficiently to risk having another child.There are many of our patients' families who never reach this point of adjustment; they never completely resolve their grief. The pediatric limb deficiency clinic team therefore not only has the patient to be concerned with, but also the parents and relatives.
As these children grow, they proceed through the same stages of development as anyone else. In infancy, the accomplishment of normal motor milestones should be facilitated. A passive arm may offer balance or a prop for sitting and crawling. A prosthetic leg becomes necessary when it is time to pull to stand. Develop-mentally oriented physical and occupational therapists are an invaluable part of the clinic team.
There is little sound evidence to explain why some children adapt to a prosthesis quite readily and others reject anything that is placed on them. There is, however, a difference in acceptance of upper vs. lower prosthetic limbs. Legs are required for mobility, and as soon as the child appreciates this, the prosthesis rarely comes off. Upper-limb prostheses, on the other hand, have varying degrees of acceptance.
The upper-limb prosthesis is not able to replace a missing part to the same degree that a prosthetic leg can. At best it is a tool, and if it doesn't enhance function, it will be rejected.
There have been several studies of rejection of upper-limb prostheses by children. Few sound conclusions have been reached. Clearly, cosmesis and function are two major concerns. A third factor, acceptance by the parents of the child's disability, may be more important.
The fact that a cosmetic hand is easier for a parent to accept may have a far greater impact on whether or not it gets worn than what the child thinks of it. Also, prosthetic wearing practices by the child are used as a behavior to influence their relationship with their parents.
When pediatric amputees reach adolescence, they undergo the same intellectual and emotional changes that other adolescents face. The limb deficiency makes this adjustment that much more difficult. Frequently a limb is rejected as the child is confronted with a new group of peers. They don't want to be "different.'' As, it is hoped, acceptance into the group occurs, the limb goes back on to aid with function. This concern can pertain to lower-limb prostheses but applies much more so to upper-limb prostheses.
Lower-limb prostheses may be worn because they are needed for ambulation, but the wearer may go to extremes to hide them. They may avoid swimming and clothing that fails to mask the limb loss such as shorts or dresses. These actions reflect the acceptance by the child of his own body image to a greater or lesser degree. Upper-limb prostheses tend to be rejected outright when there is frustration with self.
In considering all of these growth and adjustment issues, there is little question that the child is not just a small adult. The clinic team is necessary to bring together professionals with expertise in addressing these many adjustment issues.
In 1954, the need for an organized approach to the management of juvenile amputees across the country was discussed at a meeting in Grand Rapids, Michigan. Subsequently, Gerald F.S. Strong, Chairman of the Prosthetics Research Board, appointed an interim committee of ten members to pursue the issue. Dr. Charles H. Frantz chaired the first meeting at UCLA in 1956. The group officially became the subcommittee on Child Prosthetic Programs within the National Academy of Sciences Prosthetics Research and Development Committee in 1959. The goal of the subcommittee was to raise the standards of prosthetic care for children in the United States. Prior to this time prosthetic components were oftentimes not available in pediatric sizes. Prescriptions were withheld until the child started school and was therefore deemed to need a limb.
To begin the dissemination of information and the establishment of clinic criteria, four major symposia were sponsored by the subcommittee to reflect the state-of-clinic expertise during the 1960s. By 1970, the subcommittee was charged to enlarge its sphere of activity to include children's orthoses and mobility aids. Under the guidance of Hector Kay, Assistant Executive Director of the Committee for Prosthetic Research and Development, the annual conferences were expanded to include cooperating clinic chiefs and their team members. The Association of Children's Prosthetic/Orthotic Clinics has held an annual interdisciplinary conference since 1972. It is now the primary forum for the exchange of information on the limb-deficient child in North America. Members include not only individuals but also the clinic teams as a unit. This recognizes the importance of the team approach. As stated earlier, the limb-deficient child has multiple needs that can only be addressed by the team.
Children have many unique prosthetic needs. As their minds and bodies are growing, so are their residual limbs. Frequent socket revisions or replacements are necessary to accommodate this growth. Lambert has reported that children followed at the University of Illinois required a new lower-limb prosthesis annually up to the age of 5 years, biannually from 5 to 12 years, and then one every 3 or 4 years until 21 years of age.The need for frequent and regular checkups by the clinic team is obvious.
The durability of the young healthy tissue on the residual limb of a child is quite different from that of the dysvascular adult amputee. Consequently, alterations in fit are much better tolerated. Nevertheless, the frequent changes necessary present an economic concern. To lengthen the useful life of a prosthesis, materials that are easily modified and lengthened should be used. In addition, it should be noted that durability of children's prostheses is more important than cosmesis. In that regard, soft covers, while cosmetically desirable, are easily destroyed by the abuse children give them. Above all, prostheses must facilitate function. Those that the child must be careful of should be avoided.
Healing in a child is much different than in the adult. Skin is much more elastic and will better tolerate stretching to cover the end of the residual limb. Skin grafts will frequently mature sufficiently to tolerate direct weight bearing as well as the shear forces experienced with socket wearing.
The skeletally immature child relies on growth of the residual limb to maintain sufficient length for good biomechanical strength later on. This is generally not a concern with the congenital amputee. As a rule, the relative length discrepancy experienced in a congenital limb deficiency is maintained. One must, however, not leave this to chance. When planning the proper time for surgical intervention on a proximal femoral focal deficiency (PFFD), for instance, proper use of serial scan-o-grams is necessary. With the advent of newer techniques of limb lengthening and deformity corrections, proper documentation of growth potential is increasingly important.
Residual-limb length is of vital concern for the acquired amputee. The concept of preserving as much length as possible should be considered, especially by the use of disarticulation rather than transosseous ablation. For example, since 70% of the growth of the femur comes from the distal femoral physis, a long trans-femoral amputation in a 2-year-old becomes very short by the time that child becomes an adult. A knee disarticulation will avoid this problem. If a knee disarticulation is done too close to the time of physeal closure, on the other hand, the relative retardation of physeal growth on that side may not be sufficient to avoid an overly long, uncosmetic thigh. The solution to this is a distal femoral epiphysiodesis. This provides end-bearing ambulation with shorter length that will allow trans-femoral knee components, with resultant good sitting and standing cosmesis.
There is another reason to perform joint disarticulations rather than diaphyseal transections in children whenever possible. This is because the major complication of amputation surgery in children is bony overgrowth. It does not occur with disarticulations but frequently follows metaphysealor diaphyseal-level amputations. The incidence of this complication is variously reported in the range of 10% to 30%. Histologically, this is appositional bone growth of the remaining diaphysis. It is clearly not growth from the remaining proximal physis. Various techniques of handling the bone and periosteum during amputation have failed to decrease the incidence of this complication. Silastic caps or plugs have been tried, but the results are disappointing. Marquardt in Germany suggests transplanting a cartilaginous apophysis from the ilium or preserving an epiphysis from the amputated portion of the limb. Usually there is bursal formation over the end of the bone that can become exquisitely tender. Occasionally, skin breakdown occurs, and the bone may penetrate. Socket modification can delay revision, but once the residual limb becomes pencil shaped, revision is necessary. This is often required more than once until skeletal growth ceases. The residual limb does not need to be appreciably shortened overall since the appositional growth effectively adds length to the bone.
There is one area where the option of preserving length at all costs must be carefully exercised. This is the post-traumatic partial-foot amputation. For example, forefoot amputation due to lawn mower injuries frequently leaves an infected residuum with plantar scarring. While it is advantageous to be able to walk barefoot without a prosthesis, making a functional partial-foot prosthesis, especially for a less-than-optimal partial-foot amputation, is technically challenging. Concerns related to cosmesis, comfort, and function are very difficult to satisfy. Frequently a Syme ankle disarticulation fitted with a prosthesis is the best option. It is very cosmetically pleasing in a child, where malleolar size is not a problem. Nevertheless, after investing a lot of time and emotional effort in preserving length at all costs, the family is often unwilling to consider a revision as an alternative to a very clumsy partial-foot prosthesis. This problem should therefore be carefully considered in the initial treatment of each partial-foot amputation.
In the past, age appropriateness for prosthetic prescription was related to the purported ideal age at which a child could use an upperor lower-limb prosthesis. Now it pertains to appropriate ages for specific terminal devices and feet. There has also been an effort to develop criteria for the prescription of costly myoelectric limbs for very young children. Some clinics are claiming functional capabilities occurring earlier than we know them to happen in sound limbs. What is needed are controlled studies to evaluate the functional appropriateness of prescription ages. A recent collaborative study by a member of Shriners Hospital Clinics has demonstrated equal acceptability by the very young of body-powered or myoelectric-powered cosmetic hands.
Lower-limb components are being proposed for the pediatric population based on successes with adults. It is often asked whether dynamic-response feet for children should be prescribed. Due to the small body mass of the child and the frequent need for new limbs due to growth, their efficacy needs to be demonstrated.
In the chapters that follow, a number of topics unique to the limb-deficient child will be addressed, including acquired amputations (Chapter 32). The epidemiology of injuries causing traumatic amputations must be studied to learn how to provide a safer environment for our young. Lawn mowers, farm instruments, and recreational vehicles are all hazardous to the inexperienced.
The International Standards Organization (ISO) has recently adopted a definitive classification system for congenital limb deficiencies (Chapter 33). No longer is it necessary to learn a series of ancient language roots to describe our patients. This new system, utilizing just four words-longitudinal, transverse, partial, and total-has been accepted by the International Society for Prosthetics and Orthotics and the Association of Children's Prosthetic/Orthotic Clinics. It will allow for a more concise data base and communication of statistics on an international basis.
Other areas of interest are the surgical and pros-thetic/orthotic management of upper-limb deficiencies (Chapter 34A and Chapter 34B). Reluctance has been expressed in the past for doing revision surgery on upper-limb amputees. It is time for this issue to be reconsidered. Prosthetic prescription, i.e., body vs. myoelectric power and tool vs. cosmetic hand terminal devices, should be addressed. There is good evidence that very young children are able to use myoelectric limbs. Is it necessary, advantageous, and cost-effective? More studies are needed to answer all of these questions. The developmental approach to upper-limb prosthetic training is discussed in detail (see Chapter 34D). As children grow and develop, especially in their early years, their motor skill capabilities change rapidly. Prosthetic components and training must change along with them.
The two primary considerations to be addressed in the area of lower-limb deficiencies are the unique nature of some of the reconstructive surgical procedures for congenital deformities and the fact that prosthetic design must take into consideration the factors of growth and durability (Chapter 34A and Chapter 34B).
To conclude the discussion of the child amputee with a chapter entitled Special Considerations is most appropriate (Chapter 36). The needs of the limb-deficient child are indeed special as this introductory chapter has sought to point out. The sections on the multiple amputee, tumor salvage procedures, and recreational concerns address the new frontiers being developed in the field of juvenile amputee management.
- Aitken GT: Osseous overgrowth in amputations in children, in Swinyard CW (ed): Limb Development and Deformity; Problems of Evaluation and Rehabilitation. Springfield, Ill, Charles C Thomas Publishers, 1969.
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- Kruger L: Unpublished data.
- Kubler-Ross E: On Death and Dying. New York, Mac-millan Publishing Co Inc, 1969.
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- Meyer LC, Sauer BW: The use of porous, high-density polyethylene caps in the prevention of appositional bone growth in the juvenile amputee: A preliminary report. Inter-Clin Info Bull 1975; 14:9-10.
- Patterson DB, et al: Acceptance rate of myoelectric prosthesis. J Assoc Child Prosthet Orthot Clin 1990; 25:73-76.
- Swanson AB: Bony overgrowth in the juvenile amputee and its control by the use of silicone rubber implants. Inter-Clin Info Bull 1969; 8:9-18.
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- Weaver SA, et al: Comparison of myoelectric and conventional prostheses for adolescent amputees. Am J Oc-cup Ther 1988; 42:78-91.
- Wilke H: Presidential Guest Speech. 1989 Annual meeting of the Association of Children's Prosthetic/Orthotic Clinics.
Chapter 31 - Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation Principles