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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.
  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


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