Fabricating Pediatric Orthoses: More than just Smaller Orthoses

I'm not a people person. I've always preferred the quiet companionship of a room full of tools, but children are another story. During my brief stint as a clinician, I enjoyed the diagnostics, the design, and even the interaction with other medical professionals, but not so much the patient interaction—except for the children. They never complained, they always tore up everything we made, and they were, for the most part, unstoppable! I loved their willingness to overcome any obstacle just to do the simple things in life like run, catch a ball, or just walk next to their parents and hold hands. Because of this, I've always tried hard to make sure that we do everything we can to meet the challenges presented by pediatric patients.

Pediatric orthoses are not just smaller versions of adult orthoses. The diagnoses are different, the patients' activity levels are different, and there is a much greater need for adjustability. Children may have everything from mild muscle abnormalities to profound neurological and musculoskeletal deformities. These factors present challenges in adult-sized devices but are even more complicated when the devices we make are as small as pediatric orthoses frequently are—but it's always worth it.

Managing the orthosis with a child's growing anatomy can be difficult. With most adults we see the volume fluctuations as more of a global change. In children, however, the growth pattern is rarely uniform across the entire device. Most often, a child's feet experience linear growth at a much faster rate than they do medial-laterally, so we generally plan accordingly. Of course, depending on the diagnosis, this is not always the case. Sometimes the child's feet will actually expand in circumference at a greater rate than they grow linearly. It is difficult to strike a balance between providing growth adjustability and maintaining the proper function of the device because too often, when we seek to do the former, the results are detrimental to the latter. If the device doesn't function, fit is irrelevant. Things like multiple layers of removable liners, or segmented plastic sections that allow for linear elongation, can allow for extended use as the child grows; however, these solutions may add bulk and weight that make the device unusable from the beginning.

The best way to avoid this is to make an orthosis that fits well but will need to be modified frequently to maintain that fit. Thermoplastics that can be adjusted for increasing circumference and joint attachment methods that can allow for linear adjustments are usually best. Instead of using full liners, which add bulk, use spot pads to pad only the bony prominences. This will make it easier to heat and change plastic parts without sacrificing comfort.

If you attach any joints that are necessary for the design to the exterior of the device with screws, you will be able to adjust for linear growth much more effectively than if you use internal joints or attach joints with rivets. But even with these precautions, you should be prepared to change out the sidebars when they exceed safe dimensions. These few changes will yield an orthosis that will fit longer and still be strong enough to take the abuse most kids will dish out.

No one word exemplifies the primary goal of the pediatric orthosis like the word "tough." The abuse it will have to withstand is incredible, and the engineering can be hard to do. Olefin plastics are known for their toughness and, as such, they are a good match, but this type of plastic may not provide the desired rigidity. In these cases, composites are a good option, but pairing advanced fibers with a thermoplastic resin is paramount. You will, of course, lose some of the adjustability when using composites. If you keep the high-strength fibers to a minimum by using a combination of narrow gauge, fiber braids like Ultra-G®, and a more flexible material like perlon for the bulk of the orthosis, you can retain a lot of the adjustability while still providing the strength required.

Components will also experience heavy wear so you will need to be able to change them easily. Modular bars are helpful, and monolithic thermo-insertion joints; for example, Tamarack Flexure Joints, are great because you can easily replace them as they wear out. For sidebars on a pediatric orthosis, we usually think of aluminum because of the weight, but in reality a thin, stainless steel bar will frequently weigh about the same and be significantly tougher. If the device is going to be exposed to repeated bending forces, as is common with genu varum or genu valgum, the stainless steel sidebars will handle this stress much better.

Strapping will also need to be evaluated. Dacron® or leather-backed straps will add a substantial level of toughness with a minimum of bulk. You may even consider using smaller plastic buckles, which can be tougher and also resist a child's urges to remove the orthosis.

As rewarding as pediatric orthotics is on a personal level, it has frequently been the least professionally viable. At first glance this always seemed unjust, but inadvertently it lead us to examine our treatment protocols and develop more cost-effective techniques and novel approaches to help some of our most deserving customers.

Tony Wickman, CTPO, is the CEO of Freedom Fabrication, Havana, Florida. He can be reached at