Custom (prescription) Foot Orthotics are specially made devices designed to provide relief from painful foot and ankle conditions by changing the ground to foot relationship. Just as eyeglasses change the light that meets the retina, thereby “correcting” vision problems – orthotics change the way the ground meets the foot, and in so doing, change the way your foot functions. With eyeglasses, when you take your glasses off, you are back to seeing with impaired vision. Orthotics are similar – they don’t provide permanent “correction”, but when they are being worn, they accommodate the structural or functional problems that are causing painful symptoms. The one exception to this is with young children – orthotics can bring about permanent changes if they are worn before the growth plates of the bones have closed (between ages 4 and 14). But beyond the age of 14, orthotics will not bring about permanent changes.
Over-the-counter or off-the-shelf shoe inserts can add additional cushioning and support, but they’re not made to address your specific foot diagnosis. Only a custom made, prescription device can fully address your unique foot structure and function.
Some shoe store personnel or other physicians may tell you that you don’t need hard (rigid) orthotics — but the only way to adequately control the motion of your foot requires something that is strong enough to withstand ground reactive forces of weight-bearing. Much of the foot’s function is determined by the position of the rearfoot, and only a rigid orthotic provides enough support to hold the rearfoot (calcaneus or heel bone) in its proper vertical position and balance the forefoot to rearfoot alignment.
Rigid orthotics can be made from a variety of materials, and the physician chooses the best material based on the type and level of activity the patient engages in, workplace environment (ie: standing on cement floors all day or climbing up and down a ladder all day) and weight. There are also many different types of top covers and padding that can be used to add cushion and make forefoot accommodations.
How should the cast or measurements of your foot be obtained?
There are many ways to obtain the specific information about your foot that will be sent to the lab that will fabricate your custom orthotics. Some practitioners will have the patient stand in a box of “bio-foam” and get an impression of your foot. While this method might be ok for a non-functional insert, it is not recommended when fabricating custom, functional orthotics. The best method involves casting the foot to get a plaster impression (negative cast) of the foot while it is non-weight bearing and being held in a “sub-talar joint neutral” position. The sub-talar joint is a major joint in your rearfoot that allows your foot to move on multiple planes and adapt to uneven terrain. It is the joint that governs the overall function of your foot. By capturing your foot in this “sub-talar joint neutral” position and getting a non-weight bearing plaster impression, the lab is able to fabricate the orthotic with the appropriate degree of correction by working from a neutral cast.
The podiatrist should perform a range of motion exam that will reveal how much motion is present at each joint in your feet and ankles. Some feet have too much motion in certain joints, and some have inadequate motion. Muscle testing should be performed to find out if there are intrinsic weaknesses of any muscles, tendons or ligaments. This information could be critical in understanding the full reason behind the symptoms. Another very important part of our evaluation is a gait analysis. A well-trained biomechanist will pick up on subtle things that occur during a gait analysis that help him/her understand what is causing foot pathology. Some things are not so subtle – the orientation of the forefoot or rearfoot may be skewed or you may have instability of certain joints — but if your physician doesn’t watch you walk, chances are they could miss some important findings.
There are far too many structural or functional deformities to address, but suffice it to say that a complete and thorough examination needs to occur for the physician to be able to gather all pertinent information for the prescription writing process. That information gets translated into numbers on the prescription form and lines and special notations on the casts. The lab will then take that information and pour “positive” casts, make cast corrections based on the podiatrist’s prescription and vacuum mold the orthotics from the corrected casts.
At Central Carolina Foot & Ankle, we don’t cut corners with our prescription foot orthotics. We take the time to perform the examinations needed to gather all information, and we use one of the best labs in the country for orthotic fabrication. If you think you need prescription foot orthotics, we are just a phone call away.