Orthotic Technology

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“Orthotics; Biomechanically, the Tools of Our Trade”

When it comes right down to it, if you take “accommodative or bulk” type orthotics out of the equation, there are really only two general categories of functional orthotic technologies.

First, there is the Root type or traditional functional orthotic which is manufactured based on the biomechanical model that we learned in school. They are based on the traditional “Root and Weed” theories.  The cast you send in to a typical lab then gets “cast corrected.”

Cast correction is a process where some plaster is added to the medial arch. This lowers it to allow the various segments of the foot to function as per the school biomechanical model.

We are not disputing it is in fact “functional.”  However, the resultant orthotic is much flatter or lower than your patient’s medial arch when you rest the foot (in a corrected position).

You may have noticed that when you position a patient’s foot on top of their orthotics, and the foot and ankle are in their most corrected or ideal positions, you can generally stick two or three fingers between the patient’s foot and the orthotic. This again is the intended result of cast correction as it is stated and incorporated into the manufacture of that type of orthotic.

Then there is a type of orthotic collectively known as the “total or full contact” orthotic. They are manufactured utilizing different principles and algorithms.  These most importantly neither include nor require any cast correction or manipulation. 

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The total contact concept, although getting some press in recent years, is not exactly a brand new concept. It has taken advantage of the relatively new plastics at hand today. These were not available fifty or so years ago when the UCBL, Shaffer plate, Whitman Plate etc. came on the scene. 

From an academic viewpoint as well as drawing from my own personal clinical experience, I would like to make a comment or two about each of these technologies as I have both fabricated and dispensed orthotics from each technology over the many years that I have been dealing exclusively with biomechanics and orthotics. 

The difference between the orthotics produced from these two very different technologies lies in the word “control”. Hands down, I am able to control and manipulate my patient’s gait much more efficiently and effectively with total contact orthotics when compared to what I was able to achieve using standard Root type devices.  

The main reason for this is the component of cast correction and manipulation that occurs during the fabrication process of the traditional root type orthotic as previously stated.

The total contact orthotics do not employ any cast corrections or manipulations.  As a result, you get a much more intimate fit up into the arch and along the entire plantar surface of the foot. This then provides a much greater degree of mechanical control. That is why I can say with no doubts or reservations that clinically I can control any given foot better with a full or total contact orthotic.

Mechanical control is important to manipulate the bones of the foot into a much more optimal and stable position -- so that they can do what they were naturally designed to do. This is the basic idea behind total contact orthotics. Let me expand on the theory of this.

Foot orthotics are not meant to replace the function of the foot, they are only meant to augment and enhance the foot’s ability to function.   

To that end, there is an inherent stability geometrically speaking with respect to the bony architecture of the foot when the articulating surfaces of the bones of the foot are in an optimal or near optimal alignment.

Just like a roman archway has a “key stone” in the center of its arch, so does the foot. In the foot the “key stone” is analogous to the navicular and or the medial cunieform.

If one knocked out the key stone in the center of the roman archway, the entire archway would collapse.  Likewise when the bones of the foot are out of their “optimal or maximally congruous” alignments there is a dramatic decrease in the geometric stability of the arch which allows the navicular to drop excessively.

This dropping action of the navicular is analogous to the key stone of the roman arch being knocked out of place and subsequently the bones of the foot collapse.  The geometric stability of the arch is only possible when the bones of the foot remain at or near their optimal or maximally congruous alignment. When that alignment is compromised or not maintained, so goes the stability and integrity of the foot’s arch and pathologic pronation begins to occur.

This is somewhat oversimplified. But it is quite accurate to say that the locking action of the bones of the foot is dependent on the articulating surfaces of all of the bones of the foot being maintained at or near their optimal or maximally congruous positions.

To further demonstrate this point, have you ever noticed that you can lean down with your hand on any given orthotic’s arch and cause it to “give” slightly with just a few pounds of pressure?  But if a 140 lb woman can compress the orthotics that a 240 lb man is wearing with lets say forty pounds of force, how then do those orthotics have any beneficial effect for the 240 lb man?

The very simple answer is if the orthotics can keep the bones of the foot at or near their optimal or maximally congruous positions long enough into the gait cycle (more specifically before the middle of midstance), then the bones of the foot will effectively lock, in essence turning all twenty six bones of the foot temporarily into one “functional bone” that allows the transfer of the patient’s body weight from heel to the toe without excessively lowering or “pronating” the medial arch of the foot.

When this happens, the foot’s need of “support” from the orthotic is in fact very minimal as the orthotic has done its job by maintaining the positional alignment of the bones of the foot just long enough for them to “take over” so to speak. However, if the orthotics allows the bones of the foot to collapse or “disarticulate” to any significant degree too early in stance phase, the bones of the arch loose their geometric stability as previously stated.

Then by the time the middle of mid stance occurs, the bones of the foot are collapsed and subsequently remain collapsed with no hope of “un-collapsing” or re-supinating because the man’s full weight is now over the collapsed foot, holding it fixedly in place. This is in fact when all the damage occurs as the patient ultimately pushes off of an unlocked and unstable foot. 

What is the point? The total contact orthotics, because of their intimate “total contact” fit secondary to having no cast corrections or arch fill added, passively maintains the bones of the foot at or near their optimal or maximally congruous positions.  This then allows the bones of the foot to lock and do what they were naturally intended to do; lock together to act as a stable base and to allow an even and non-pathologic transfer of weight along the entire foot during stance phase of gait without any significant support required from the orthotics. 

Now in this new light when you take a look at the cast corrected Root type orthotics, as they have much less intimate contact and fit with the arch of the foot, they allow more room or range for the bones of the foot to move and subsequently allows them to drop, collapse or pronate more extensively. This then allows the bones of the foot to be in less optimal or maximally congruous positions than they actually could or should be. A patient then has a greater tendency to continue to pathologically pronate through and over a traditional Root type device with corresponding results that can be far less impressive than you could have otherwise achieved with a more efficient device.

In summary, my clinical experience with both orthotic technologies has shown me conclusively that the full or total contact orthotics has a greater capacity to control the foot and subsequently the entire kinetic chain. This among other things allows me to dramatically increase my orthotic indications and allows my practice to cast a wider net for potential orthotic candidates. This in turn allows me to help more patients as well as provides an additional revenue source that if done in volume can be quite significant. Your orthotic success is not only based on volume, it is based on results. If you want a quick gauge of your overall orthotic efficacy, take a look at the statistics presented in the sales and statistics section of this web site.

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