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Challenging the foundations of the clinical model of foot function

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Jan 31, 2017.

  1. Jeff Root

    Jeff Root Well-Known Member

    Kevin, other than you and Eric, what other U.S. Podiatrists are lecturing about Tissue Stress Theory in the states? Who are the leading U.S. podiatrists who are advocating Tissue Stress Theory and what articles or papers have they had written that would demonstrate their attempt to promote Tissue Stress Theory?
  2. Jeff Root

    Jeff Root Well-Known Member

    We have had the Root vs. Tissue Stress Theory debate many times before. The reason I originally responded to this tread was to contest the practicality of the conclusion of Nester et. al. which stated “We recommend that clinicians stop using sub-talar neutral position during clinical assessments and stop assessing the non-weight bearing range of ankle dorsiflexion, first ray position and forefoot alignments and movement as a means of defining the associated foot deformities”. It appears to me that the conclusion was developed prior to the study and the study was an effort to support the conclusion, which by the way relies on the measurements of one “experienced” practitioner. In our previous debates, as in this one, I think it is obvious that there are elements of Tissue Stress Theory in Root Theory, and Root Theory in Tissue Stress Theory. Basic terminology is obvious proof of this.

    In addition to terminology that is based on, and is better defined as a result of Root’s neutral position classification system, a large percentage of prescription foot orthoses have the all the elements of the Root Functional Orthotic. They are produced from a non-weightbearing cast of the foot from which a positive cast is created. The positive cast (or scan) is oriented in the frontal plane, has a medial and lateral expansion/fill, is manufactured using a thermoplastic shell, has an intrinsic or extrinsic forefoot post (ff correction) and an extrinsic rearfoot post. In many instances, these “different” theories result in the exact same orthotic prescription. The Tissue Stress approach is logical and augments what we have been doing for a long, long time.
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  3. mazzopod

    mazzopod Member

    I have been following this debate for the last few days and have come to the conclusion that we as Podiatrists worldwide we are now ready to accept change, but are still tied to our "biomechanical roots" as taught to us many years ago. Merton Root opened a new world of biomechanics for me in the early 80's when I was a student and then when I became a lecturer I conveyed the same principles to my students for many years. Thanks to people like Kevin Kirby, Eric Fuller, Craig Payne, Trevor Prior, Beno Nigg and many other experts, I changed my approach to clinical assessment and orthotic prescription due becoming aware of not just skeletal bone structure and fixed deformity buy also to rest of the foot and lower limb structure which included muscles, tendons., ligaments ...... In other words soft tissue structures which played an important role during the gait cycle and foot function. TST is of vital importance in assessing pathology in all foot types, especially in sports injuries, the diabetic foot, rheumatoid foot and many foot disorders associated with increased work load. I believe that there is no ONE theory that can dominate and resolve all foot pathologies, but a better understand as to why and how the lower limb and foot function normally is of utmost importance to all of us.
    We look forward to the new theories but think that letting go of our old ones is going to take some time. Strange how Root biomechanics earned me a living for a very long time .........
  4. Maurizio:

    Thanks for the great reply. In know you to be a man that has been around almost as long as I have. You have studied and attended lectures to stay current. You don't want to be just another podiatrist, but to be the best podiatrist you can for your patients. Unfortunately, there are plenty of others, especially here in the United States, who have been around a long time and want to only do things as they were taught back in podiatry school.

    Eric Fuller and I coauthored a book chapter on Tissue Stress Theory which we finished writing 12 years ago, in February 2005. Unfortunately, the book and our chapter was not published until 8 years later in 2013 (Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert SF, Curran SA (eds):
    Biomechanics of the Lower Extremity: Theory and Practice, Volume 1. Bipedmed, LLC, Denver, 2013, pp. 205-264).

    In this chapter, Eric and I wrote a whole section to the chapter on this same issue which I have attached below. Remember we wrote this chapter over 12 years ago. It is amazing to me that we are still having this same discussion with the same people now in 2017! How many times around the stump we must go, I don't know. I'm sure they will still be debating this issue long after I am no longer around.

    Like you said, we have people who have been around for many years such as Benno Nigg, Eric Fuller, Craig Payne, Trevor Prior and myself who are lecturing on Tissue Stress Theory and similar concepts. We also have younger individuals such as Simon Spooner, Ian Griffiths, Javier Pascual Huerta, and many others around the world who are currently lecturing on Tissue Stress Theory. There is no doubt in my mind that Tissue Stress Theory, in some way, shape or form will move many of the dogmatic teachings of Subtalar Joint Neutral Theory into the history books, and out of the clinics. But when that occurs is anybody's guess.

    All in all, it is an exciting time in foot and lower extremity biomechanics. However, sadly, in my own country, biomechanics takes second place to surgery in all the current seminars. This is the reason I enjoy lecturing internationally so much (Belgium in March, Toronto in May, and Manchester, UK, in June). Non-US podiatrists are very interested in biomechanics....US podiatrists...not so much.


    History of Tissue Stress Approach In Medicine

    When confronted by a different method of treating
    patients with mechanically based pathologies of the foot and
    lower extremity, a health professional may immediately ask the
    question, "Why is a new approach to mechanical foot therapy
    needed since there has been a generally accepted approach that
    has worked quite well over the last forty years?" To obtain a
    broader view of why it is sometimes necessary to change our
    ideas regarding new information in any field of science or medicine,
    it is important to take a brief look at the history of scientific
    progress to see how and why change occurs.

    Science does not always progress continually and systematically
    forward. In his classic treatise on scientific progress,
    Kuhn has described a process in which a group of people will
    have a generally-agreed-upon set of ideas, described as a paradigm.
    1 A group of scientists can base its research questions on
    these generally accepted ideas. Like scientists, a group of medical
    practitioners can also have a generally-accepted model by which
    to treat patients. Over time, research in a paradigm progresses and
    there may be a number of observations that become inconsistent
    with the existing paradigm, which Kuhn terms as "anomalies." If
    the anomalies are only minor, then the paradigm will change to
    accommodate the anomalies and survive. However, if
    there are enough anomalies, then the original paradigm is discarded
    and a new paradigm will emerge to replace the old paradigm.
    Throughout history, this process of changing paradigms
    has occurred numerous times within both the fields of science and

    The history of podiatric biomechanics and mechanical
    foot therapy has also progressed in jumps from paradigm to paradigm.
    2 From 1845, when one of the earliest built-up in-shoe
    leather custom insoles was first described by British chiropodist
    Lewis Durlacher, to the foot orthoses developed by Whitman,
    Roberts, Schuster, and Levy in the century that followed, ideas
    have been continually changing regarding the principles and
    practice of mechanical foot therapy.3, 4 One of the largest paradigm
    shifts in mechanical foot therapy occurred in the late 1950s
    when Dr. Merton Root developed his Root Functional Orthosis,
    which remains the model for most modern foot orthoses that are
    in use today within the podiatric medical profession.5

    Root and his coworkers also published a foot classification
    system in 1971 that compared an individual foot with an idealized
    normal foot.6 However, over the last few decades, some of
    the ideas of the Root paradigm have come into question.2, 7, 8
    Other individuals have noted that new paradigms are being proposed
    to take the place of the Root paradigm.2, 9 Kuhn has noted
    that throughout the history of science, when there is discontent
    with an established paradigm, multiple paradigms are proposed to
    serve as replacements, and eventually one paradigm becomes the
    dominant paradigm for that period in time.1

    The application of the principles of Newtonian mechanics
    to the analysis of human locomotion has been occurring within
    the scientific community from as early as 1836.10 These early
    efforts at the mechanical analysis of gait were limited by their
    inability to accurately measure the forces and motions needed for
    their calculations.11 Cavanagh described how the work of Jules
    Marey and Edward Muybridge, two of the earliest pioneers in
    gait analysis, contributed improvements in the measurement of
    forces and motion that led to further advances in applying
    mechanical analysis to gait.11 Around the turn of the twentieth
    century, attempts to apply mechanical analysis to gait were limited
    by the fact that it took over 1000 hours to process the data generated
    from a single step.12

    In more modern times, improved measurement techniques
    have lead to the exploration of assessing clinical pathology
    with mechanical measures and opened the potential for actual
    measurement and prediction of pathology.13, 14, 15 The technique
    of modeling has been shown to have positive results in the prediction
    of the stresses that occur within the tissues of the body.16

    The idea that the pathological stresses on an injured tissue
    should be considered more than the apparent "deformities" of
    the foot and lower extremity in determining an appropriate
    mechanical foot therapy is not totally new. In 1992, Kirby noted
    that by using models of the foot and lower extremities, an intelligent
    prediction could be made as to whether one of the structural
    components of the foot is under tensile, compression, and/or torsional
    loading stresses during gait.17 He felt that the analysis of
    externally measurable deformities of the foot and lower extremity
    did not give nearly enough information so as to allow prediction
    of the mechanical behavior of the foot during gait; and was,
    therefore, an insufficient method by which to prescribe the best
    foot orthoses.

    In 1995, McPoil and Hunt promoted the idea that
    mechanical foot therapy should be directed toward resolving tissue
    stress in what they called "the tissue stress model." 8 They
    noted that the tissue stress model serves "as the basis for developing
    an examination and management paradigm for treating
    individuals with foot disorders." They also claimed that nonreliance
    on the use of "unreliable measurement techniques" currently
    in use to measure deformities within the podiatric profession
    was one of the benefits of the tissue stress model.

    In 1996, Fuller reviewed the concept of tissue stress
    along with the use of computerized gait evaluation techniques
    and modeling of the foot and lower extremity to help predict the
    stress in a specific anatomical structure.18 More recently, Fuller
    has promoted the idea of a tissue stress treatment model that
    explains how a clinician can use rearfoot and forefoot wedging to
    serve as a basis for mechanical foot therapy.19 Kirby has also
    recently reviewed the biomechanical nature of tissue stress and
    the clinical application of the tissue stress approach to mechanical
    foot therapy in which a stepwise approach to its use was introduced
    for the clinician.20

    Even though the medical literature had only discussed
    the importance of using the tissue stress approach a little over a
    decade ago, this approach of mechanical treatment of foot and
    lower extremity pathology has been used for many more years
    with gratifying results by the authors in their own clinical practices.
    The concepts of subtalar joint axis spatial location and rotational
    equilibrium help explain the production of abnormal internal
    stresses within the tissues of the foot and lower extremity.
    This emerging model of mechanical foot therapy may serve as a
    new paradigm of mechanical treatment of foot and lower extremity
    pathologies. It is highly possible that further refinements in
    this model of mechanical foot treatment will eventually add yet
    another paradigm to the treatment model alternatives for clinicians
    who specialize in treatment of mechanically.

    [From: Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert SF, Curran SA (eds): Biomechanics of the Lower Extremity: Theory and Practice, Volume 1. Bipedmed, LLC, Denver, 2013, pp. 205-264.]

  5. drhunt1

    drhunt1 Well-Known Member

    You nailed it Jeff Root. I don't expect Dr.s Kirby or Fuller to answer your question about how many Pods in the US are actually lecturing on TST. And as you've stated...multiple times on this blog, your fathers' work was not complete...it was a work in progress. It was up for the rest of us to "fill in the blanks" and take his epic work to another level. For instance...TST suggests that we abandon the "STJ neutral" idea. Really? It's staring all of us in the face when we examine patients with their feet suspended off the examination chair. That foot also realizes STJ neutral, (or very close to it), when they ambulate in swing phase of gait...or when they are getting a rebound in BB, or when they go up to slam a volleyball. It's right there...right in front of us. I dare the TST adherents to argue otherwise.

    They also state we should disregard NCSP or RCSP, when the evidence we see in our own practices dictates otherwise. Everyone can practice the way they want to, but I read Kirby and Fuller's chapter on TST, (quite the cure for insomnia, btw), and one cannot glean a miniscule amount of help in determining how to prescribe an orthotic based on that information.

    Podiatrists needed a starting point in order to collect their own ideas on how best to treat patients successfully...and your father gave us that. Was it complete? As you've stated...no. Was it a great work to direct us to order a better, more satisfying result? Unquestionably. As far as I can determine, TST is a lazy man's way of trying to drive square pegs into round holes. It doesn't solve any redundant problems. What are those, you might ask? Those are the problems we witness, time and again, that walk into our offices. Sure...their feet may differ, but the presentation of pain and the area of complaint is, perhaps, the same. Different feet + same approach...similar maladies + consistent treatments= success.

    Bottom line...after years of debate...nothing has really changed here at PA. We read the same responses, same back slapping antics for those that adhere to TST, while dismissing the excellent work-in-progress your father left with us. TST never has really solved any of the foot problems we treat daily...and I've asked politely, (and otherwise), for anyone to point out where I'm wrong. You could hear a pin drop. While very few of us have, or take the time to bisect a calcaneus, or even perform a cursory biomechanical examination...it doesn't mean we shouldn't. While money is drained out of the "system" for performing surgery...the one area that we SHOULD own, is foot biomechanics. Yet here we sit, almost 50 years after your father published his books, still arguing over the contents or trying to design a better mousetrap. One can easily surmise, then, that your fathers' work was spot on target. No wonder many other specialties in medicine still consider us a peripheral subspecialty, not to be taken as seriously as we should...and why chiropractors and physical therapists are making orthotics.
  6. All the science deniers in the house as usual then.... Y'all keep moving those goalposts, but never carry out any research of your own to validate your opinion pieces. Tell you what, why don't you design a study that would once and for all settle the arguments..... That way when the study was performed to your methodology, you'd have no more comeback and then we could move the profession forward rather than constantly being dragged backward by the anchors of your vested interests. Jeff Root, why don't you fund Chris Nester's next PhD student with some of the profit you make from selling your foot orthoses built on your father's ideas?

    Along with others, I have spent at least the last 20 years teaching on the flaws in Root's books (they weren't even peer reviewed papers!!!) and providing alternatives to the dogma. Will this paper put the 50 year old ideas to bed for good? No, not as long as those with vested financial interests in the Root ideas have breath in their bodies and the ability to type. But it is obvious that globally we are much closer to the finish now than we were to the start. It's all over, very few individuals outside of the USA believe in the Root ideas anymore, fact. Sleep tight now America, your government has it all figured out...

    To me many of Root's ideas seem naive and callow, as they should 50+ years since they were dreamed up. Yet for 20+ there seems to have been a body trying to close down any questioning, never providing any new evidence to support their ideas, but trying to pick apart the data which refutes their claims. These "shepherds" fight to maintain their status quo with all of the efforts, but do not invest in the researchers for fear they may refute their claims.

    Sometimes I get so angry with the simple life they lead
    The shepherds smile seems to confirm my fears
    They've never questioned anything, They've never disagreed
    Sometimes I think they must have wool in their ears

    And when you see a cane I see a crook
    And when you see a crowd I see a flock
    It's sheep we're up against
    Sheep we're up against.

    Viva variation.
    Last edited: Feb 15, 2017
  7. Jeff Root

    Jeff Root Well-Known Member

    Let me state again, I’m not wanting to have a Tissue Stress vs. Root debate again. I have already stated that I believe that there are components of Tissue Stress Theory in Root Theory and Root Theory in Tissue Stress Theory. And I also stated that tissue stress has some logical, although I may have issues with how it is being implemented. I also have issue with how some people practice the “Root” approach” and I have acknowledged problems with Root theory. I’m not attempting to critique or criticize the protocol used by of Nester et. al. in their study. The only thing I’m challenging is their conclusion, which as I have stated numerous times in this thread, seems to me to be impractical, especially for DPM’s and others who utilize terminology and techniques that come from or are based on Root’s work.

    Kevin just acknowledged that podiatry here in the states is different than it is in many other countries, largely due to the fact that it is so surgically oriented. Biomechanics is applicable in both the surgical and non-surgical treatment of the foot and ankle. As a result, we need common terminology and techniques for both areas of practice. For example, the open chain ROM evaluation of certain joints is used during a biomechanical examination to make treatment decisions as to whether a surgical or non-surgical treatment approach is indicated. The conclusion of Nester et. al. is in direct conflict with this common clinical approach. As a result, I think their conclusion is ill-advised and impractical, and I know I am not alone in that opinion.
  8. As I've pointed out previously, your father didn't invent the terms forefoot varus and valgus, nor rearfoot varus and valgus; do you need me to pull those references which date back prior to your father even being a podiatrist again, Jeff? The games up, Jeff. Viva variation. Moreover, you haven't demonstrated that those measurements predict pathology yet... nor that they are key to successful orthotic management.

    You state: "seems to me to be impractical, especially for DPM’s and others who utilize terminology and techniques that come from or are based on Root’s work." I feel sorry for the American podiatrists you refer to, it must be hard if you have not stayed up to date. Yet they have had access to the same research that all other clinicans around the world have had access to. Burying your head in the sand is as useful as the Luddite solution... Is it "impractical" or impracticable, there is a difference here in the UK... yet apparently not in North America according to our respective dictionaries.
    Last edited: Feb 15, 2017
  9. Jeff Root

    Jeff Root Well-Known Member

    Simon, I did not, nor have I ever said that Root invented those terms. It appears that you did not read my previous posts on this thread:
    From post #28: "Here we are today, forty-six years later, still dealing with the same issues. One of the most critical issue is that we cannot have meaningful communication without clear and consistent terminology. My point is a simple one; the terminology described by Root et. al., which is based in part on the neutral position classification system, improves our ability to communicate within podiatry as well as with and within other disciplines."
    some cut, I posted a quote from Volume 1: "The terms, as defined by the authors in this manual, are in common orthopedic usage, but each term has been provided a strict scientific definition."

    You can plainly see, Root himself stated that those terms were in common orthopedic usage. As I have tried to explain time and time again, prior to Root there was no way to establish the presence of a forefoot varus or a forefoot valgus except, perhaps, when it existed in extremes, because no standard position of the STJ and the MTJ was used for determining and measuring ff varus or ff valgus. Root tried to improve our understanding of these terms by defining these conditions with the STJ in the neutral position and with the MTJ fully pronated. As I have stated many times before on the Podiatry Arena, this is no different than having the standard anatomical position of the body for the purpose of discussing anatomy. In the standard anatomical position, the body is erect and the palms are facing anteriorly. Having the joints of the body a standard anatomical position enables us to discuss anatomy in a more meaningful manner. Having the foot in a standard anatomical position also enable us to discuss foot anatomy in a more meaningful manner.
  10. Jeff Root

    Jeff Root Well-Known Member

    Thank you for your suggestion but Root Lab made a generous financial contribution to help fund the Motion Analysis Research Center at the California School of Podiatric Medicine in an effort to advance research. I will leave the research up to others although I am involved in an advisory capacity and my company may provide foot orthotics for a research project that is underway at the school.
  11. Jeff Root

    Jeff Root Well-Known Member

  12. NewsBot

    NewsBot The Admin that posts the news.

  13. drhunt1

    drhunt1 Well-Known Member

    Doug is on point in this article. I could add to the several questions he raised...but I believe his point was adequately made.
  14. Ben Lovett

    Ben Lovett Active Member

  15. Jeff Root

    Jeff Root Well-Known Member

    I was recently reminded of this article written by Dr. Root and I posted this elsewhere as a result. I would like to post it here because in 1982, these words were a relevant as they are today.

    The following was written by Dr. Root and clearly demonstrates his view on the future of foot orthotic therapy and was in response to an article published in Consumer Reports Magazine which was critical of foot orthotics (ref: Pacesetter Vol. 2, No. 1 March-April 1992):
    "A second major reason for the failure of podiatry to convince the public of the value of its orthoses is that the profession is using gimmicky terminology and attempting to foist it on the public. Terms like "biomechanical imbalances," "optimal functional position," and "rebalance the foot" were used by Consumer Reports as direct quotations from podiatrists. Not one of these terms makes scientific sense, and the public is knowledgeable enough to reject such nonsense.

    Biomechanics, which is a relatively new basic science of medicine, has particular value to podiatry because podiatrists primarily treat problems that are directly or indirectly caused by abnormal mechanics of the foot. Those podiatrists who have little or no knowledge of biomechanics but attempt to convince the public and the profession that they do, are distorting biomechanics, and will eventually destroy it as a valid scientific basis for understanding the foot. The science of biomechanics will continue to grow and flourish in other medical specialties but will die in confusion within the profession of podiatry.

    An orthosis that is prescribed to resist specific abnormal forces identified by examination and is designed to promote improved function of the foot is called a functional orthosis. A functional orthosis does not support the arch of the foot. A functional orthosis does not "balance" a foot. A functional orthosis does not hold a foot in any position. A functional orthosis does not accommodate lesions or painful areas of the foot. A functional orthosis only resists abnormal forces and promotes improved foot function".

    There you have it from Root's own words. A functional orthosis does not support the arch, balance the foot or hold the foot in any position! "A functional orthosis only resists abnormal forces and promotes improved function of the foot"! I wish certain people would frame that, put it on their wall and refer back to it every time they say that Root said an orthosis should support or hold the foot in the neutral position.
  16. efuller

    efuller MVP

    It's good to see we can quote this when we say that you don't need to use neutral position anymore. ;) Although it is somewhat confusing reading this and then reading Mert's description of how to make orthoses in the Clinics in Podiatry article. He describes how an intrinsic forefoot valgus is added to an orthotic. The rationale for adding that modification is.... there is a forefoot to reafoot deformity. The implied message is that the "deformity" is causing the abnormal forces. The neutral position paradigm is treating positional deformities in order to reduce abnormal forces. However, there is no evidence that these "deformities" produce abnormal forces. The point of the Jarvis paper was that the deformities were not consistent with what was seen in gait. I will agree, when looking at the extremes, there is probably some ability to predict where forces will be. The partially compensated varus foot is one where the foot is much more likely to have high lateral loads because of lack of range of motion to fully load the medial forefoot. This is a valid and important concept. However, the best way to figure out if someone has this foot is probably not to use neutral position based measurements. I feel it would be better to have the patient stand and try to put your fingers under the foot to see where the most load is. I learned this test from John Weed's lecture syllabus. Using neutral position as a reference point and dividing the "deformity" into rearfoot and forefoot just confuses the issue. If you want to treat forces, look at where the forces are. Don't look at neutral position forefoot to rearfoot measurement, especially when the foot in stance is not resting in neutral position. Look at where the forces are. Or look at the injured anatomical structure and figure out what you need to do to reduce forces on that structure.

    It is also interesting to look at Mert's quote and realize that he only said what an orthotic does NOT do. He did not talk about what it does. We've had this discussion before. I recall once we were discussing Mert's writings and I looked at a passage and I said "It's right there in black and white, Mert said that an orthosis puts the foot in neutral position." Jeff, you claimed that is not what he meant. But, an objective reading of the passage could lead to the impression that Mert thought that a neutral position orthotic put the foot into neutral position. Which leads to the question of how does a neutral position orthotic change the forces acting on the foot. We have the above how it does not work. We need to know how it does work. Does an orthotic made from a neutral position cast supinate the foot more than an orthotic taken from a semi weight bearing cast? Why? I actually believe that it is because the orthotic is an arch support. A neutral position cast will tend to have a higher arch than a semi weight bearing cast. What did Mert think about how an orthotic did work? He did write about how an orthotic did work better when the heel was balanced to vertical as opposed to NCSP. This was always a student question. If neutral is normal, why don't you balance the heel bisection to NCSP? The answer was that it doesn't work as well. It is good to know what works and what doesn't. It is also good to know how something works. It allows you to break the rules (balance to vertical) to make something work better. (Inverted orthotic, medial and lateral heel skives).

    The quote above was written in response to criticism of functional foot orthoses in consumer reports. We are going to still have the magical thinking criticism of orthotics as long as we continue to hold on to neutral position as normal. As Mert said in that quote orthotics treat abnormal forces. Holding on to neutral position is getting in the way of us looking at forces.

  17. Jeff Root

    Jeff Root Well-Known Member

    Eric, here is more from the article:
    "What is required to provide functional orthotic therapy for one's patients?
    The doctor must have a sufficient background in biomechanics to be able to identify the abnormal forces that cause a foot to malfunction.
    • The doctor must be able to prescribe the variations in functional orthoses that are necessary to manufacture an orthosis that will resist those abnormal forces.
    Some cut:
    Even the position in which the cast is poured can be critical to controlling function of a foot in certain cases. Most casts are poured with the calcaneus vertical, but in some cases it is necessary to prescribe an inverted pouring position, and in other cases an everted pouring position. The exact number of degrees for either an inverted or everted pouring position must also be prescribed".

    It is clear that Dr. Root's goal was to reduce or eliminate pathological forces to the greatest extent possible. He developed a system and outlined the ways he felt that this objective could best be achieved. Millions of people throughout the world have benefited from Dr. Root's pioneering work. So to answer your question, Mert believed that a functional orthosis worked by altering forces and that it was necessary for the practitioner to have a sufficient background in order to identify pathological forces and to have the knowledge to alter those forces to reduce or eliminate pathology.
  18. efuller

    efuller MVP

    It may be clear that reducing pathological forces was his intent, but it does not appear he had a coherent explanation for how to reduce those pathological forces. From an earlier quote we know that he did not think that an orthotic put the foot in neutral position, it did not support a deformity, nor is it an arch support. It appears the treatment protocol is take a neutral suspension cast in neutral position and then rarely alter the heel bisection on a piece of plaster and then press an orthotic on it. Where is the explanation of how that reduces pathologic forces? Magical thinking?

    I am still perplexed by Mert's quote about not an arch support, doesn't support deformity, doesn't put the foot in neutral position. Those are things that Eric Lee discussed as explanations of how a neutral position cast worked. I need to pull out the Clinics in Podiatry and see which sites Eric Lee attributed those ideas to.

    Eric F
  19. drhunt1

    drhunt1 Well-Known Member

    And you have a coherent explanation for how to reduce those pathological forces? LOL! I've read your chapter, co-authored with Kevin Kirby....yaaaaaaawn. I've read both of you discussing your "theories" on PA. As far as I'm concerned, you're blowing smoke...as most, if not all, of the TST guys are still doing to this day. I've asked this question more than once here...but I'll ask it again: What pathologies have you EVER solved using TST as the framework?
  20. efuller

    efuller MVP

    We have answered your question before. In the chapter we explained Hallux abdcuto valgus, hallux limitus and plantar fasciitis, lateral ankle instability, peroneal tendonitis, posterior tibial tendon dysfunction and sinus tarsi syndrome. Do you have any questions on, or critique of, the explanations in the chapter?
    Last edited: May 16, 2017
  21. Jeff Root

    Jeff Root Well-Known Member

    I’m perplexed as to why Jarvis et al would spend their time, research funds and effort testing Root’s theories when they could have been testing Kevin and your theories or other tissue stress theories, assuming such theories are developed enough to be testable. Makes one wonder.
  22. Jeff Root

    Jeff Root Well-Known Member

    Eric, in your chapter you and Kevin wrote: “Foot type has also been postulated as a cause of lateral ankle instability. Foot types such as a rearfoot varus or a forefoot valgus specifically have been indicated in lateral instability. The lateral ankle instability related to both of these foot types can be explained by STJ axis spatial location. Lateral ankle instability related to rearfoot varus is caused by the increased STJ supination moment that results from the plantar aspect of the calcaneus being more medially located relative to the STJ axis than would be present if the calcaneus were not inverted”.

    Pardon my confusion, but here you seem to be validating Root’s structural classification system with the use of terminology and also seem to be supporting his theory of how certain foot types react (ie. tend to compensate) to GRF. I agree that your explanation of STJ axis location adds to our understanding of foot function, but there seems to be a major conflict here with Jarvis et al, their study and conclusions.
  23. raun

    raun Active Member

    Isn’t it vaguely concluded :rolleyes:
  24. This whole debate is a complete mess as I have said before there is What Root et al said and then there are interpretations and then because of that the discussion never gets anywhere.

    The latest quote from Jeff is interesting as it seems to me that his thoughts on how and why bent pieces of plastic work, and what the intent of them will be, a changing in the thought process from the dogma of Normal and Abnormal Biomechancis

    Which is what many of us have gone through.... So maybe Eric that is why there is the hole in thought processes ?

    So where does it leave us as Podiatrists ? We can keep going around and around making interpretations of what Root et al meant or didn´t ? Or can we use the international bio-mechanics language to communicate with each other? of do Podiatrists keep working with there own interpretations of what Root et al said? Is there a better way to treat patients? I certainly think so, but Podiatry discussions won´t get anywhere like this.
  25. Trevor Prior

    Trevor Prior Active Member

    I agree Mike. Structural alignment of the foot will affect how it responds to ground reaction force but, this in turn will be affected by the degree of mobility of the foot (which varies with everyone) and what is being driven proximally. Thus, people with to familiar alignments can function in different ways and react to GRF differently.

    Thus research into the relationship to function will show little correlation as has been shown.
    Whichever approach one takes, we are trying to relieve symptoms and thus we all apply a tissue stress approach, just in different ways / different theories, often with the same results. To say tissue stress does not work is incorrect. In my opinion, TSR is erroneously linked directly to SALRE, all approaches relate to TSR, SALRE is simply a logical method, based on the principles of physics to explain how the foot responds to GRF and how it can be modified – further research is required for validation.

    To my mind, we are all clear that we have to modify the force, the research clearly indicates that reliance on STJ neutral is now history yet we can use positional alignments as part of our assessment process. After all, joint moments are the resultant of the alignment, direction and size of the force across a joint.

    I am in full agreement with your sentiment that we should look to how we can develop common terminology for all (Kevin is utilising the principles of physics and associated terminology to try and achieve this), look towards the commonality of what we are trying to achieve and then develop studies that evaluate how we make our diagnosis and develop treatment guidelines.

    At present, we are going around in circles.
  26. drhunt1

    drhunt1 Well-Known Member

    I read your chapter, Eric...and you two never really answered anything. You discussed aforementioned pathologies by utilizing your own theory, but never solve anything. I asked you above and previously what you've ever SOLVED...not what new mousetrap have you created. I believe you should examine the words of Dr. Richie and take that message to heart. In his article, he more than adequately supports the Root Theory...as do I. When you have truly solved a pathology utilizing TST...let me know...until then...POOF! I'm out.
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  28. efuller

    efuller MVP

    There are observations and then there are explanations. The observation is that an inverted heel is often laterally unstable. The Root & Weed explanation is that this is because the heel is not in line with the leg. The tissue stress approach, using rotational equilibrium looks at center of pressure and the center of pressure of ground reaction force on the entire foot to determine the moment about the STJ from ground reaction force. So when you do see an inverted heel in a foot that is not laterally unstable, you can explain that by saying that the inverted heel is not far enough medial to the STJ axis to cause a supination moment. This is a perfect example where the classic Root measurements will not explain why some inverted heels will tend to invert, and others will not. Another problem with neutral position biomechanics is the separation of the forefoot and the rearfoot. What if you have a rearfoot that will tend to cause inversion of the STJ and a forefoot that will tend to cause eversion of the STJ. If you look at the center of pressure under the whole foot, you can figure out what the ground will be trying to do to the foot.

    So, what I said is not really a validation of Root Mechanics. It is offering a different explanation of observations that were seen. Any theory on foot function has to explain physical observations.
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  30. In rereading this article that I wrote a few months ago, I think the thing that strikes me as most unusual is the fact that so many podiatrists may have not, as of yet, realized that some of the teachings of Drs. Root and colleagues have many problems associated with them. I've been lecturing on this for three decades!!

  31. efuller

    efuller MVP

    This reminds me of many of the comments I would overhear at graduations. They would often go something like this. I'm really beginning to understand surgery, but the more I look at biomechanics the less I think I understand. or another: I got A's in biomechanics, but I don't feet that I understand it. Those kinds of comments can be explained easily by the lack of coherence in Root theory. As Jeff pointed out Mert has said that orthotics don't work by supporting the arch, or supporting a deformity, or putting the foot into neutral position. What he did not say is how orthotics do work. When you look at Eric Lee's history of the development of the functional foot orthotic there are many statements that were essentially a certain thing worked. There is a disconnect between the prescription writing protocol that works and the measurements that are performed. What is truly amazing is how many instructors still just don't see that lack of connection. Those instructors are continually asked by students about that connection. The students who answered the test questions correctly still don't understand the subject. Is the problem with the students or is it with the instructors who continually ignore troubling literature that does not agree with their world view?

  32. Jeff Root

    Jeff Root Well-Known Member

    Here is the full section of this quote from Mert which I originally quoted in reply #55 above: "An orthosis that is prescribed to resist specific abnormal forces identified by examination and is designed to promote improved function of the foot is called a functional orthosis. A functional orthosis does not support the arch of the foot. A functional orthosis does not "balance" a foot. A functional orthosis does not hold a foot in any position. A functional orthosis does not accommodate lesions or painful areas of the foot. A functional orthosis only resists abnormal forces and promotes improved foot function".

    The last sentence says that a functional orthosis resists abnormal forces and promotes improved function. So he did say how he believed orthotics worked. By resisting or altering forces to improve function. I think that we can find common ground in his statement that abnormal (i.e. pathological) forces should be identified in the patient examination process. Unfortunately I think you will find many clinicians who treat with orthoses without identifying and in some cases, without even attempting to identify the source of the pathological forces. For those of us who do care about identifying the source of pathological forces, the debate stems around the best techniques and methods for doing that and, around the theories that best support our preferred approach.
  33. Bored now. "identifying the source of pathological forces"... really? Force= mass multiplied by acceleration. "pathological" you say...? Bored now...
  34. Jeff Root

    Jeff Root Well-Known Member

    And your point is?
  35. And your point is? Bring it: because I'm just in the mood for you, Mr Fireman... a) attach your labs "prescription form" b) explain how one should fill it in.... I give you ownership of that.. explain the prescription variables, and how that relates to the clinical exam I should perform to arrive at the numbers required for your form, if you would/ could/ should.... I look forward to seeing your labs form... post it up so that we might critique it.. if I want to use your lab, what clinical tests do I need to perform to prescribe an orthosis? Go on the Jeff, lets see whaT YOU'VE GOT... something ridiculous.. it's just intermission.... I've got a patient with peroneal tendonitis- what test should I perform, which boxes do I need to tick on your labs form? Show us the form, show us a ticked example, if you would.. obvs not. And you wonder why I'm bored...?
    Last edited: Jun 1, 2017
  36. Jeff Root

    Jeff Root Well-Known Member

    My point is that certain conditions increase pathological forces so the goal of treatment is to attempt to alter or reduce the forces that are contributing to the pathology being treated. Take PTTD for example. In some cases there may be early signs and symptoms of PTTD. We can often reduce or eliminate those symptoms with a relatively conventional type functional orthosis. The device will act to resist some STJ pronation moments and will support the medial arch of the foot, thereby reducing strain on the plantar ligaments and the PT tendon.

    However, in a more advanced case of PTTD that has resulted in some degree of adult acquired flatfoot, we will need to alter our treatment approach and prescribe an orthoses or an AFO that specifically addresses the increased pronation, the increased internal rotation of the tibia, the increased talar adduction and plantarflexion, the abduction of the forefoot relative to the rearfoot, and the reduction in the height of the medial arch. So we might alter our orthotic Rx and invert the heel (heel bisection), use a medial heel skive, a higher medial arch, a wide arch profile and possible accommodate any bony prominence in the talonavicular region, that might otherwise be irritated by a device that more aggressively resists STJ pronation, internal tibial rotation and forefoot abduction (i.e. excessive MTJ pronation). Adult acquired flatfoot develops as a result of decreased supination moments or increased pronation moments. Our treatment is designed to address this.
  37. Yeah lovely, but as you are not licensed as a practitioner in your country all of that is frankly hat-stand: so if you would be so kind as to answer my post... please provide a copy of your labs prescription form, give details of the tests required to complete it and provide an example of how your prescription form should look for a patient with peroneus longus tendonitis, if you would please... Jeff said: "certain conditions increase pathological forces"- nope- there you go putting the cart before the horse, again. Is this not obvious, and you wonder why I'm bored of this....? Frankly, your argument is just not good enough. Nor has it ever been for the last 20 years. Bored now.
  38. Jeff Root

    Jeff Root Well-Known Member

    The prescription is determined by a licensed doctor of podiatric medicine, not the lab. Our Rx is available online if you want to see it. The doctor uses his/her education, training and experience to develop the Rx. We serve DPM's with different philosophies and treatment approaches so the Rx is dependent on their professional judgement.
  39. efuller

    efuller MVP

    This is straight tissue stress.

    The more advanced foot that you describe will tend to look more like the reafoot valgus foot. So, if you took the prescription protocol that John Weed taught... say you see an everted NCSP you would make an orthotic with an everted heel cup, in a patient with PT dysfunction. I think we can agree that this is wrong as an everted heel cup would tend increase pronation moment from the ground.

    This is the problem that I have with the Root protocol. The prescription writing criteria are based on the inherently unreliable heel bisection. The decisions on where to put the heel bisection of the positive cast were based on what worked and not on any theoretical considerations. Rich Blake found that inverting the heel produced good results. He got a lot of grief for that branching away from Root doctrine. I don't recall what theoretical reasoning he used when he decided to invert positive casts. There may have been more theory to what Blake did than to what Root did. Remember the old student question of...."If neutral is normal, and NCSP is 5 degrees inverted how come you want me to balance this cast to vertical?" Instructor: "Don't think about that. Just balance it to vertical because that is what works". This is the disconnect between theory and practice that continues to confuse students and practitioners.

    Tissue stress is much simpler. A patient has PT dysfunction. You want to reduce load on the PT tendon. You do that by shifting the center of pressure more medially with a heel cup with a varus wedge effect (medial heel skive or inverted cast bisection) . The medial shift in center of pressure will decrease the pronation moment from the ground.

  40. Jeff Root

    Jeff Root Well-Known Member

    Rich originally developed the Blake orthosis to address the varum angle of the lower leg when treating runners. If a patient had 5 degrees of heel eversion ROM available and had a five degree varus position of the lower leg at heel strike, Rich believed that the foot would try to pronate beyond its ROM. He theorized that by inverting the cast, the inverted heel cup would act to resist pronation better than a vertical heel cup. Rich received tremendous support from Dr. Root and Root Lab in helping him develop and refine the technique. The device was found to have significant benefit in treating highly pronated feet in non-runners and children.

    Root did not believe that a functional orthosis would support a rearfoot varus foot type in an inverted position, so he opted for a vertical heel position. That was when heel cups were typically 10 to 12 millimeters. With the advent of much higher heel cups, it became common practice to make orthoses inverted when indicated. The Blake Functional Orthosis, with its deep heel cup, influence others to use higher heel cups on non-Blake devices. As a result, we make many orthoses with inverted heel bisection positions today.

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