So, What's Up With Those Orthotics, Eh?

If we think of the shoe and it's two primary components between your foot and the ground, namely, the insole and the outsole, as "translators" between your feet and the ground, then orthotics are the equivalent of a translator of a new language. This is because they alter the relationship between your feet and the ground in more significant ways than the flat surfaces of the insole and the outsole of the shoe. Where your feet apply too much pressure, orthotics redistribute that pressure, and the forces that cause the pressure, so that both your weight and the forces - shock, or impact; and torque, or rotation (with it's sidekick, shear forces) - are supported and modified toward a more efficient set of actions. One of the primary goals of functional foot orthotics is to reduce excessive pronation where that pronation is causing pathology, while another is to improve the posture of the foot during heel strike and through mid-stance phase of gait (when the foot is fully on the ground.)

But these are not the only aspects of a functional foot orthotic as they might be applied to someone with post-club feet. With PCF, it is seldom possible to approach the biomechanics of such feet the same way one approaches less pathomechanically defined feet. But the tools can still be used even if the outcome is often significantly different. The primary consideration should be around three factors: sufficiency of range of motion of the subtalar and midtarsal joints; degree of arthritic changes present; and degree and duration of inflammation or edema. Too little motion available reduces the functional effectiveness; significant amounts of arthritis suggest the need to reduce motion further, not enable more; inflammation especially long standing strongly influences the nature of the surface of any orthotic as to how the foot responds to pressure. A hard device will be less well tolerated than a softer one, or at minimum, a softer material on top of the more rigid material of the orthotic itself.

This brings us to the function of materials as they apply to both the devices and to the foot. You can easily suspect I will frame this in terms of a trade-off, and you would be correct. Materials have to be considered on the basis of their strength, their moldability, their longevity, and their memory. Lets talk about this last item first - memory.

In materials, memory speaks to how well a material will return to its original shape after each "deformation." Think of the pillow you sleep with - when your head lays on the pillow, it "deforms," that is, it conforms, or moves away from, the forces applied to it by your head - it's weight and its shape. When you take your head off the pillow, it returns (depending on the material used to fill that particular pillow) to its original shape. The speed of return, and the degree of return, are both components of the material's memory. If it did not return to that original (or closely) shape, it would rapidly become harder and less comfortable, and you would wish to replace it much sooner than you had been led to believe you would have to. Likewise, if it took several days to return to the original shape, the results would be nearly the same, as far as your comfort and your expectations. These issue apply as well to the materials used to cover and to form your orthotics. They must show a high degree of memory if they are to be worth using.

Longevity is a property of memory, as well, but it also is dependent on other aspects such as chemistry and heat. The environment inside our shoes is fairly tropical, and often quite acidic, as well. Our body generates heat, and the friction of our feet inside our shoes generates heat and moisture. A part of the moisture is sweat, and sweat has many chemical components, salt being one of the more corrosive. all the materials inside your shoes - whether shoe or orthotic - are subject to these chemicals and the moist heat. And one of the side effects is the intrusion of fungal infections, that also contribute to the in-shoe environmental impacts. The other two components affecting longevity of materials are one's weight, and one's biomechanics. So you can see that, tradeoffs are inevitable - there is no such thing as the perfect material, no matter what the advertising might say.

Moldability, or the tendency of a material that permits it to be molded into a new shape, through heat and pressure, and then to retain that new shape with little long-term deformation, is critical for most materials used to make orthotics. We can differentiate materials that can alter their shape through heat and pressure from materials that are shaped via mechanical means, such as graphite, which uses a chemical process, or milled plastics, which start as a block of raw material, and then are shaped by a milling process. Both of these last two approaches have gained in usage over the past decade, but heat molding is still used for many orthotics.

Strength, as you might imagine, is a product of all of the above. Strength refers to the original material's characteristics to resist change, and to how that resistance changes after the material is shaped into the final device, as well as the environment the material must deal with every day. It also refers to the material
s ability to resist tearing, or breaking under a load.

So consider how difficult it is to achieve the right set of trade-offs - there are anywhere from 3 to 4 different materials in use in any given pair of orthotic devices. There is the primary formable material - plastic (of many different types, depending on the approach desired by the doctor) or carbon graphite. Then there is the post, or heel stabilizer material, and the top cover material, and possibly additional material for the extension to allow for a plantarflexed metatarsal head, for example. Each material chosen for the given part of the overall device must be chosen based on how the various parts are supposed to act. The top-covering material must be the best at resisting moisture and acidic conditions, as well as being somewhat resistant to fungus. It must be able to conform to the curvature of the heel cup portion of the body of the orthotics, and it must have a decent longevity. It must offer some cushioning without taking up too much space in the shoe. And it must not contain chemicals that some may be allergic to, such as latex.


More Than The Sum of Its Parts

An orthotic device is more than its material composition - it must also be designed and formed properly, and it must fit within the shoe properly. If the device, once ensconced inside the shoe, makes the shoe too tight to allow the foot to fit inside with comfort, it won't do you much good, so the shoe and orthotic must be considered as a whole. And the type of shoe the device is worn in has a significant impact on the success of the orthotics, as well. if you want to wear 4 inch heels, well, good luck with that - they most likely won't fit in the shoes, your feet definitely won't fit in them, and the position of your feet will make the devices useless, which pretty much wastes everyone's time and effort in that particular project.

So picking the right shoes, if you don't require custom-made shoes, is a matter of several factors - extra depth for the inclusion of the orthotics; good toe room; a stable insole material that will support the orthotics and your feet without breaking down quickly; a well-balanced outer sole; and a good closure system - laces, or velcro, or straps - loafers and other types of slip-on shoes will have a less effective outcome because the foot will likely slip off of the orthotics inside the shoes. For some, who may require better ankle support and who need to control their subtalar motion better, a high-top shoe will be a better choice. Which brings up the perpetual issue of fashion.

Anyone with significant foot problems, CF or otherwise, would most like to be as much like everyone around them as anyone else does. Who wants to call extra attention to the source of one's pain? But there are realities that cannot be avoided - what makes some shoes fashionable is what makes them problematic for people with significant foot problems. Again, it's about tradeoffs, pure and simple. For me, it has always been about comfort over fashion. I tend to think people look best when they are happiest, not because they have the latest fashion trends writ large. A person wearing the latest fashion, yet walks in such shoes in great discomfort, tends to cause any beauty they possess to go missing. IMHO, that is.\

Hopefully, this brief overview of orthotics and the considerations that must go into their construction and their use has given you more tools when communicating with your doctor and/or orthotist. It helps to know what to ask, and how to explain where things could have gone better in your previous devices, so as to get improvement from one pair to the next. Us clubbies, unfortunately, should not expect a perfect pair the first, and likely as not, even on subsequent pairs of devices. We have a very difficult set of conditions compared to people with lesser foot problems, and therefore we are often more the expert on our own feet than most doctors are. That, as they say, is just the way it is.