The intent of this chapter is to highlight special topics as they pertain to the prescription of prosthetics and orthotics in the pediatric population; for an in depth review of these topics please also see Chapters 48 and 79. A detailed evaluation and history are important in developing a comprehensive management plan in the pediatric rehabilitation population. In addition to etiology and level of involvement, patient goals, level of development, family support, and compliance should be considered. Often children require the assistance of a parent or caregiver for donning and doffing a device as well as proper wear and care of the device. Unlike the adult patient, the child requires more frequent follow-up and adjustments as a result of growth and activity. This chapter discusses pediatric prosthetics and pediatric orthotics. Each section describes common etiologies and design considerations. Treatment decisions to manage both immediate and long-term conditions in the pediatric population should be made with input from the complete medical team, including but not limited to the patient, the patient’s family and/or caregivers, the physician, the prosthetist-orthotist, the physical therapist, the occupational therapist, the recreational therapist, the nurses, and the social worker.

Incidence and Etiology

The etiology of the amputation or limb deficiency is an important factor in prosthetic design, alignment, and component selection. The limb loss or deficiency can be congenital, caused by disease such as infection or tumor, or the result of trauma. Approximately 30% of patients have acquired amputations compared with 70% with congenital limb anomalies.¹ Congenital limb anomaly incidence is 5 to 10 per 10,000 live births,² with upper limb deficiencies being three times more common than lower limb deficiencies.³

Common Considerations

There are many factors to consider when deciding on prosthetic treatment for the pediatric candidate. Socket fit is fundamentally important in the overall fit and function of the prosthesis. If the socket is comfortable and well fitting, the patient should benefit from the functionality it is intended to provide. If it is uncomfortable, the child will reject prosthetic wear. The prosthetist’s expertise will ensure a properly fitted socket. Some common considerations specific to the pediatric population in the prosthetic treatment design discussed in this chapter include frequency of adjustments and replacements, family involvement, residual limb length, bony overgrowth, alignment, activity-specific prostheses, and component size.

Frequent Adjustments and Replacements

Due to growth and higher physical demands of pediatric patients, more frequent adjustments and replacements should be expected compared with adults. Typically, a pediatric prosthetic socket should last 1 year, but this can vary depending on growth spurts and activity level.⁴ An endoskeletal prosthesis is designed with some postfabrication adjustability to allow for adjustments of the prosthesis and replacement of components (e.g., foot, terminal device, or socket) as needed. Components can be changed to accommodate growth, activity levels, and functional demands of the pediatric patient. There are several ways to accommodate growth in the design of a prosthesis to delay the need for replacement, the most common of which are described in Table 68–1. Both longitudinal and circumferential growth should be considered in the design of the socket. As the pediatric patient grows, a single component can be replaced (e.g., foot, pylon, interface, socket), or the patient may be indicated for a whole new prosthesis.

Residual Limb Length

The length of the residual limb affects the control of the prosthesis and design selection. Typically, the longer the limb, the more control the patient has of the prosthesis due to the longer lever arm. A very long or very short limb results in limited component and design options. With disarticulation, the pediatric patient preserves growth plates, retains weight-bearing capability, and avoids bony overgrowth.^1,5,6 However, because the disarticulation is through the joint, aesthetics can be a challenge when trying to match the intact side. For example, a knee disarticulation prosthesis will have better control than a short transfemoral prosthesis, but the prosthetic knee center will be lower than the sound-side knee center.

Family Involvement

Family commitment begins with understanding and acceptance of the condition, prognosis, and treatment recommendations. When the patient is very young, the prosthetic treatment plan is decided by the family or caretakers. With age, the child should be more involved in decisions about prosthetic design and treatment. In addition, the very young child will require assistance with donning and doffing, which should progress to independent donning and doffing.

Bony Overgrowth

Bony overgrowth or periosteal overgrowth results from transdiaphyseal amputations³ and is most frequent at the humerus and then the fibula, tibia, and femur⁴ (Fig. 68–1). To avoid bony overgrowth, it is preferable to perform joint disarticulation. This also preserves the growth plate.⁵ When the soft tissue is unable to grow at the same rate as the underlying bone, the result is painful overgrowth at the distal end, and this frequently results in an inability to wear the prosthesis due to pain and discomfort. A bursa is a good indication of a bony overgrowth developing.³ Most often surgical intervention is indicated to reduce the pain associated with the overgrowth.⁵

Alignment

The prosthetist will properly align the prosthesis for maximum comfort and functional capabilities. Without proper alignment of the prosthesis, the child may experience limb or joint discomfort or exhibit gait deviations. Many congenital limb deficiencies have varying angular deformities that must be accommodated in prosthetic design, which can come at the expense of aesthetics.³ Alignment of the lower extremity prosthesis should match that of a normal child’s gait and weight-bearing alignment. For example, an infant typically walks with wide-based gait and flexed at the hips and knees, and therefore, the prosthesis should be aligned similarly.⁶

Activity-Specific Prostheses

While the standard prosthesis is typically used for everyday activities of daily living (ADLs), school activities, and around the home and community, activity-specific devices are designed for a single intended activity. Some examples include a running or swimming prosthesis, neither of which is able to be used for everyday walking. For the upper extremities, such prostheses can be designed with a variety of terminal devices for a gymnastics arm or a violin-playing arm, among many other options.

Component Sizes and Options

Fewer component options are available to the pediatric population than to the adult population. Goals and expectations should be discussed with the family and prosthetist to determine appropriate component selection for the child’s functional level, age, and physical presentation. As the child grows, more components will become available.

For the upper extremity pediatric prosthetic candidate, functional outcomes and success of the prosthesis should be based on each patient’s needs. Thorough discussions with the patient and his or her family about expectations and goals are paramount in prosthetic treatment decisions. Component selection and design can vary depending on whether the prosthetic goals are aesthetics, prehensile function, activity-specific function, or a combination of each. In addition, professional training with an experienced occupational therapist is essential for the prosthetic user.⁷

Fitting Timeline

For upper extremity limb deficiencies and amputations, prosthetic fitting should begin when the child can sit and reach across midline or around 6 months of age.⁷ The first prosthesis should be a passive prosthesis with a passive terminal device (TD) such as an open hand, crawling hand, or mitt, without articulation.⁷ Suspension should be self-suspending or sleeve suspension, with attempts to minimize harnessing.⁷ Prehensile TDs, such as hooks and hands, can begin to be introduced as the child shows the cognitive ability to control these devices. The transradial amputee can be fit with a single grasp and release TD when the child is around 1 year of age.⁴ Articulating the joints for the transhumeral amputee typically begins around 20 months of age with a passive friction elbow, with or without a locking feature to allow for prepositioning the limb for bimanual activities.⁷ The combined motion of glenohumeral extension, glenohumeral abduction, and shoulder depression required to activate the elbow lock is generally attained around age 5.⁸ For the shoulder disarticulation infant, a passive friction shoulder can be introduced when sitting balance is achieved.⁷

Passive Prostheses

For the very young child, a passive prosthesis can aid in achieving early milestones such as sitting by using the prosthesis as a prop for balance or crawling by using the prosthesis to help.⁷ As the child grows, a passive prostheses can continue to be used as a lightweight option for cosmetic reasons.

Suspension

Much like the adult counterpart, traditional harnessing, self-suspending socket designs, and gel sleeves provide good upper extremity suspension options. Self-suspension frequently eliminates the need for harnessing but may require the use of a pull sock.

Terminal Devices

TDs can be passive, electric, voluntary opening, or voluntary closing. Voluntary opening designs for the pediatric population include a hook, the CAPP TD, or mechanical hands. Although the glove that goes over the mechanical hand can improve aesthetics, it requires more force from the child to operate the device and adds to the overall weight.⁹ The CAPP TD by Fillauer, with a wide palmar space and spring-loaded prehension, is a good initial TD because it has the capability of cable activation later.⁷ The electric hand does not require the same force to operate but comes with added weight. Electronic pediatric hands are categorized in one of two grasp patterns through adolescence—palmar prehension (hands) and oppositional grasp (Electrohand by Ottobock)—but they are only available in palmar prehension into adulthood.⁷

Myoelectric

The externally powered prosthesis should begin with single-site activation and progress to dual-site activation as the child exhibits cognitive capabilities and site control. An example of single-site activation includes voluntary opening and automatic closing. The myoelectric components add weight and bulk due to a heavier electric hand and the addition of sensors and a battery to the design. However, the externally powered devices eliminate cabling and add aesthetic value. Electric elbows are available to the school age child, like the VASI 8-12 elbow by Liberating Technologies, which is an example of an electric elbow available to children and preteens.⁷ Consulting with the local prosthetist is important to understand what components are available and best suited to the patient.

For the pediatric lower limb prosthetic candidate, prosthetic treatment varies depending on etiology, age, level involved, activity level, and the space available between the distal end of the residual limb and the ground. As with upper extremity involvement, professional training with an experienced therapist is important for prosthetic success.