Dear Dr. Glaser,

I enjoyed reading your paper to PRESENT for podiatric residents.  As a past instructor of Biomechanics at the Ohio College, I am happy to see that we are not dead. Just a few comments.

Root taught me that if you get the patient just a few degrees out of pronation, the improvement is exponential. No one could disagree with you that improving foot posture as you describe would be better, but you hit the nail on the head when you said that the MLA discomfort overrides the improved foot posture.

Do you feel that it is easier to treat a hyperpronation by treating the deformity that caused the hyperpronation, i.e., forefoot varus, equinus, etc. It just seems to me that mechanically it is easier than to stick something under the foot and raise the arch. I think that is why Root had such a low profile orthotic.

This is not to say that you have made some really excellent points. I am very interested in your MASS casting. I am going to guess that MASS doesn't stand for Massachusetts. Does this casting technique capture the forefoot to rearfoot relationship or neutral rearfoot position?

I look forward to your response.

—Michael Forman, DPM
Cleveland, Ohio

Dr. Forman,

Thanks for the comments and questions. 

Over-pronation is a progressive disorder, thanks to body weight, gravity and hard floors. The Second Law of Thermodynamics, also known as the concept of entropy, states that all complex systems tend to devolve over time to a less organized, more random or disordered state. Supination requires anti-gravity work to maintain whereas pronation is a result of mere structural relaxation and disorder; pronation = the entropic state of the foot. Or, to put it more simply, things fall down rather than up, following the path of least resistance. At some point the pronation devolves to a point where tissue stresses exceed healing rates and the patient exhibits a symptom. Dampening the last bit of pronation range is therefore all that is needed to mask symptoms without making a significant positive effect on foot function. That is why research comparisons of custom vs. prefab orthotics generally demonstrate no significant difference between the two types. Some, in fact, show that prefabs are better than customs.

Pronation	Supination

Before there can be any meaningful or useful debate about orthotic intervention strategies we need agreement that, whenever possible, restoring normal posture and function is better than merely masking symptoms. It may seem obvious that any conscientious doctor would agree that restoration of posture and function is preferable, but I have found, particularly among the many biomechanists that post on Podiatry Arena, that is not the case. Many of them argue that reduction of tissue stress without significant change in posture/function is sufficient, that mere symptom reduction is a satisfactory, even an ultimate, goal. They are apparently unconcerned or in denial that prefabs work as well as customs. As I have stated elsewhere in this series, the podiatry profession must do better than that to earn their title of primary foot specialist.

In every other sort of orthopedic practice it is well understood that normal joint alignment or posture is critical for establishing normal function; that dysfunction creates pathology. Somehow the rules got changed for the foot and many of those treating foot diagnoses have been schooled that posture and function are not important, or at least behave as if it is unimportant. As dedicated foot care specialists we should be determined to make care of the foot as function-oriented as any other joint complex in the body.

The entire subject of MLA discomfort has been misunderstood for some time. There is both an historical and a technological reason for the nearly universal assumption that high orthotic arches = pain. In the 1800s, foot doctors frequently diagnosed their over-pronating patients with “weak foot”. To overcome their patient’s weakness they purposely designed horrific, high-arched and completely rigid devices in order to make them use their pretibial muscles to actively lift their arches off the devices for some relief. Of course, most people not being masochists, they refused to wear the devices and this gave high-arched devices a bad name.

In more recent times, most attempts to give higher support to the arch have been painful. The more interesting question is why. Ever since Root, neutral position has defined the corrective paradigm of the foot as 50% pronated. It turns out that if you give a patient that full amount (50%) of available arch in an orthotic, it is just high enough to be painful. This is because discomfort usually occurs in the arch due to impact forces as the foot drops down from a fully supinated position and hits the orthotic. The foot has so much range to drop through that it develops momentum and therefore uncomfortable impact as it finally hits the support 50% down. Ironically, current mainstream orthotic technologies cause arch pain because they don’t make them high enough.

The main reason we fear to venture upwards of the 50% neutral ceiling is that we do not have an accepted new corrective paradigm that is able to predict the right extent of arch height (supination) for any particular foot. To address this I have proposed MASS position as this paradigm (and have utilized it now for over 12 years with many thousands of [comfortable] patients). A MASS position orthosis does not allow the foot to accelerate into the support. By matching the shape of the individual's foot, the orthosis is in full contact (much like full contact plaster casting in DM neurotrophic ulcers). Full contact disperses the corrective forces evenly across the entire foot such that the force per unit area is comfortable. Patients do experience pressure, but rarely discomfort….unless we mis-calibrate the product.

The other commonly perceived barrier to MASS position technology is the absence of forefoot to rearfoot pathology assessment: the too familiar concepts of forefoot varus/valgus, etc. –again from Root. The unquestioned assumption underlying these diagnostic concepts is that an observed mis-angulation of the forefoot to the rearfoot in the open chain “neutral” position is somehow a mechanical factor during stance phase. In order to actually create a mechanical issue on the ground, the foot would need to be rigidly fixed in the mis-angulation which would be extremely rare. Any foot that rigid would not be a candidate for orthotic intervention anyway. So these concepts, while observable and identifiable in Rootian methodology, have no important relevance to foot function on the ground. To clarify: There is little support for the interrater reliability of these static measurements; even if they could be measured reliably there exists significant doubt as to their relation to dynamic gait; and even if there was a relationship to dynamic gait, achieving the desired outcome with an intervention to address the perceived deformity has not been well demonstrated.

In fact, while there are many varieties of foot anatomy and points of relative flexibility or rigidity, all feet are:

I would venture that 99% or so of feet fall under the second category (see above) and define the daily patient population coming to us for help. The vast majority has some degree of over-pronation and therefore is functionally deficient in supination. So the real, common and pertinent deformity is the lack of sufficient supination from late midstance to forefoot loading. That is the deformity that MASS position theory addresses.

MASS stands for Maximal Arch Supination Stabilization. It is the most arch (supinated posture) that a person can tolerate comfortably at midstance with the heel and forefoot on the same plane….that of the floor. It is a posture that is far more supinated than neutral.  How much correction do you want any patient to have?  I would think as much as they can get without over correcting and causing new problems. 

Please answer me this:  If we know that the foot ideally heel strikes in supination, then why would we allow the foot to pronate all the way to “neutral” before even thinking about controlling its motion? Then most labs arch fill so that the foot does not hit the orthotic until much later.  What is the science behind arch fill? It was primarily used to decrease warrantees. Orthoses made in true neutral fall in the dysfunctional zone which is a high impact area. Lowering the arch to the pathologic zone where the ligaments are slowing down pronation and then allowing the  orthotic to simply, and mostly by virtue of the compression of soft tissues, cause further dampening of the impact of pronation itself, is enough to hide symptoms without changing the kinematics of gait.

Thanks for your interest. I love these types of discussions.  Please ask more questions….it is the basis of all research and knowledge.  I don’t have all the answers but we are doing research in several universities and learning more and more.

Sincerely,

—Edward S. Glaser, DPM
Sole Supports (www.solesupports.com)
[email protected]

GRAND SPONSOR

MAJOR SPONSORS