We have reviewed the first three columns in the FootID Pro Configurator thus far, “Congruency”, “Frame”, “Frame Options”, and now we move on to the fourth column, “Posting”. A quick review of the steps needed to get this far in the FootID Pro application might be helpful at this stage. When you open the app, you will see an orange button labeled “Start building your orthotic”, when you click this, you are given the option of selecting a new patient or existing patient. After selecting this next option you will be given the further option of selecting what type of foot model you wish to choose, either existing or new. The next option will be “Select Orthotic”, where one can choose from the three Root Models or the various active, dress, pathology, therapeutic or UCBL models. You may also have stored templates of your favorite configurations here. The next step will now lead you to the configurator, where you can truly customize your orthotic devices to address your patient’s unique biomechanical needs.
For those of you not familiar with orthotic posting, they can be categorized as either rearfoot or forefoot, extrinsic or intrinsic, and varus or valgus. The types of posts can be mixed and matched, for example, you may choose an extrinsic varus rearfoot post, with an intrinsic valgus forefoot post. The amount of posting or degree of varus or valgus correction incorporated into the posts, should be derived from findings uncovered during your biomechanical assessment and gait analysis.
The first field in the “Posting” column is “Rearfoot Post”. Within this field you can choose between extrinsic and intrinsic posts, and between varus and valgus posts. For many models there is a pre-selected default denoted by an orange check mark in the upper right of the field. The default may be easily overwritten as needed. Clicking the chainlink icon in the middle upper part of the field will allow you to differentiate between left and right options versus bilateral. Please note that a zero degree post is neither varus or valgus so it doesn't matter if you use the varus or valgus option when selecting a zero degree post. Further descriptions of the rearfoot posts can be found on the KevinRoot Medical website.
Rearfoot Varus Extrinsic Rearfoot Valgus Extrinsic
Rearfoot Varus Intrinsic Rearfoot Valgus Intrinsic
The amount or degree of posting can vary from zero to six degrees, either in the varus direction or valgus direction. An extrinsic varus rearfoot post will be higher or thicker on the medial side and will assist in controlling the ability of the heel to evert, or the subtalar joint to pronate. Conversely, a valgus extrinsic post will be higher on the lateral side, to inhibit lateral instability as well as having other clinical indications. Extrinsic posts are usually rigid or semirigid EVA material, alternative materials for extrinsic posting may be available upon request. Intrinsic rearfoot posts are incorporated into the plantar surface of the heel cup of the frame and are most effective when limited space within the shoe is available.
Please note that the angle of the rearfoot post will be reflected in how the distal edge of the orthotic frame sits relative to the ground. A varus rearfoot post will elevate the medial distal edge of the orthotic when sitting on a flat surface, and valgus rearfoot post will elevate the lateral distal edge of the orthotic frame.
The next field is titled “Varus Motion Post”. A varus motion post is an angle in the frontal plane on the plantar surface of an extrinsic rearfoot post that enables the orthosis to invert and to evert back to its original position. The function of a varus rearfoot post is to enable the device to be inverted at heel strike and to evert after heel strike to enable subtalar joint pronation. The options here are, two, four and six degrees of motion of the rearfoot post. For example, if you order a zero degree rearfoot post with four degrees of motion, the outside or lateral aspect of the post will be ground to an angle of four degrees varus and will function at initial heel strike, the medial aspect of the rearfoot post will reflect the zero degree measurement. This will allow the heel to evert four degrees during the entire heel contact phase.
It is my opinion that the proper use of posting is a main differentiation between a true custom foot orthotic device and an off the shelf arch support. Another differentiation is the expertise of the biomechanics practitioner. Creating effective orthotic devices is both a science and an art. Oftentimes, follow up and evaluation of the devices, once dispensed, is critical to successful outcomes. Adjusting posts is a common and easy method to change the corrections built into the devices, should it be deemed necessary.
