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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. I suspect they still play in your house every Friday, Jeff. Never going to move on your position though are you, Jeff? As any more evidence comes into contradict your stance, you'll just make the requirements more and more specific, until you die. We'll have shit like "but I personally, the son of Merton Root didn't actually do the measurement, the negative cast, prescription form, plaster prep, vac form and grind of these devices used in the study that showed they didn't work, therefore your research doesn't prove that my fathers theories are invalid" Then, ultimately we'll end up with- "my late father didn't make these devices- so your research does not count"... and you wonder why I'm bored.
     
  2. Jeff Root

    Jeff Root Well-Known Member

    When you have a better patient evaluation and treatment system, with emphasis on system, that is evidence based, teachable and guarantees better patient outcomes then I will be happy to abandon my old ways and follow down your road of success. I'm waiting to receive my Sole Supports orthotics because Ed Glaser cast my feet and is sending me a complementary set of his devices. Who knows, in a few weeks I may become a proponent of MASS theory. Actually I have never considered your state of boredom. Fortunately I have a very full and rewarding life and never find myself bored.
     
  3. efuller

    efuller MVP

    You cannot generalize your comment about joints functioning at end of range of motion to all joints. The tarsal metatarsal joints and the calcaneo cuoboid and the Talo navicular joints should all be dorsiflexed to their end of range of motion, or at least to the point where the plantar ligaments resist some of the load caused by ground reaction force and body weight. (This is one interpretation of what Root called "locking" of the MTJ. The casting position he proposes is one where the midtarsal joint is maximally dorsiflexed, well at least the lateral column)

    A valgus wedge will not necessarily reduce tension in the peroneal muscles and compromise the tendon stretch reflex. The CNS determines the tension in the tendon. There can be active tension in the tendon when the STJ is maximally pronated and when the STJ is 4 degrees from maximally pronated. Sometimes the goal is to reduce tension in the peroneal tendons, for example peroneal tendonitis. The problem with peroneal tendonitis is that there is too much tension in the tendon because the tendon needs to apply forces to keep the foot plantigrade when ground reaction forces are causing the STJ to supinate because of a laterally deviated STJ axis. In this case, the hope is the valgus wedge reduces the tension in the peroneals to more normal levels.

    Another case is sinus tarsi syndrome. In this case, Talliard has shown that there is a decreased firing of the peroneal muscles when there is pain in the sinus tarsi. I believe later papers showed that with sinus tarsi syndrome there is an increased peroneal reaction time. (Increased peroneal reaction time is a cause of lateral ankle instability) This all makes sense if you see peroneal inhibition as a pain avoidance response. Talliard also showed that with local anesthetic in the sinus tarsi you saw a return to normal firing pattern of the peroneal muscles in those that had an abnormal firing pattern without local anesthetic. What I think Talliard got wrong is the notion that cause of the abnormal firing pattern was a impaired proprioception because of ligament injury. Proprioception is the sensory part of ankle control. The motor control is either a spinal reflex or a CNS command. I would agree that too large of a valgus wedge could create sinus tarsi syndrome (I've done this in my own foot) and this could lead to inhibition of the peroneal muscles to avoid increased pain in the sinus tarsi. This is why the maximum eversion height test is important. You don't want to force the STJ beyond its end of range of motion. You need to know how much eversion range of motion there is. (You can do this with all of Daryl's calculations and measurements of forefoot to rearfoot in various STJ positions, or you can just look at the foot when it is everted in stance.)

    So, if one were to do a study on ankle instability and use a 7 degree valgus wedge I would predict that valgus wedge would not work in those people who did not have that much eversion height and those poeple with average to medial STJ axes and already had sinus tarsi pain. The valgus wedge would work for those who had that much eversion available and laterally deviated STJ axes. This is the problem with doing the same intervention with all subjects, because feet are different (this is one of the more important things that I learned from Mert Root's writings).

    So Doug, even though there is not research specifically showing what I say is true, indulge me my theorizing as I indulge you on your theorizing about putting the STJ in neutral is the best position for treating ankle sprains and that there is a damping mechanism related to STJ position. I would just like theories to be plausible and makes sense with the anatomy, physiology, and physics.
     
  4. Eric,
    I am not theorizing at all. I am simply summarizing what other researchers have reported in quality, peer reviewed studies. As echoed in many other posts on this thread, the term "neutral position" has been used frequently by other disciplines to describe a preferred position of function of the subtalar joint. Indeed, several of the studies I reviewed in my own paper used that terminology and strategy to implement foot orthotic treatment of chronic ankle instability. The role of the subtalar joint in providing an ankle strategy of postural control has also been well studied and my own description of the damping mechanism has been used by other investigators in this field. I continue to marvel at your persistence in taking an authoritative position on a subject which you appear to have very little expertise. You have speculated that a specific patient population is at risk for an ankle sprain without any studies or data to justify such a proclamation. You then make a specific treatment recommendation for this group of patients which has not ever been tested or verified for efficacy. Perhaps the tone of your authoritative stance could be re-set and you could clarify that your treatment recommendations are purely speculative?

    Doug
     
  5. efuller

    efuller MVP

    Which papers showed that neutral position was an ideal position for treating ankle instability. Which definition of neutral position was used? If that was different than Root neutral don't you think it would have been more precise to say that it was a different neutral from the one that we were discussing? By the way, how did the researchers in that study put the foot into neutral position to find out it was better than some other position?

    Doug, just because I disagree with you does not mean that I have very little expertise. Attack the argument not the person. I admit that what I say is theoretical. I went into detail about how my theorizing could still be true with regard with the literature that you have cited.


    I agree that relative external rotation of the tibia, relative to the talus, is what will rupture the anterior talo fibular ligament. What forces will adduct the talus relative to the tibia? The STJ has to be supinated enough for ground reaction force to be in a position to create the forces that will rupture the ligament. Do you believe that in a typical ankle sprain you can tear the ATF with the STJ in a pronated position? A paper may have said the primary motion is.... One needs expertise to critically analyze the literature.

    Doug, do feel that Mert Root should have had less of an authoritative tone and said that his treatment recommendations were purely speculative because they have not been vetted in peer reviewed literature?

    Eric
     
  6. Eric,
    I am not on trial here. Are you asking questions because you need to learn more ? If any of the readers who have reviewed your CV and publications believe that you have expertise in the treatment of chronic ankle instability, they can stayed tuned for the next edition of your unsubstantiated treatment recommendations. I have done my best to defend the true science of what we currently know about this condition but will not continue to debate your distorted descriptions of the etiology, pathophysiology and treatment of chronic ankle instability.
     
  7. scotfoot

    scotfoot Active Member

    Doug ,
    With regard to a STJ "damping mechanism" and chronic ankle instability the link below may be of interest to you . I can say that privately the theory outlined has been read and considered plausible by a number well respected authorities .
    Cheers
    Gerry
    Intrinsic foot muscles .The heart of balance ? - Biomch-L

    https://biomch-l.isbweb.org/threads/30914-Intrinsic-foot-muscles-The-heart-of-balance
    1. Cached
    17 Jan 2018 - 4 posts - ‎1 author
    So can the head of the tibia balance in this way on the talus/calcaneal unit ? I think the answer may be yes , at least for postural stability in the medio lateral direction . Previously , Luke Kelly (1) has shown that the intrinsic foot muscles can control foot posture including the condition of the medial longitudinal ...
     
  8. Trevor Prior

    Trevor Prior Active Member

    On the first point yep, that is the aim. Of course, what attempting to achieve plantargrade needs to consider is what is happening proximal to the foot and ankle. The reality will be that some structures will be relatively more stressed and others less stressed dynamically in this case, because the structure has been altered which is why structure cannot be ignored.

    On the second point, this would be a discussion I would love to have verbally as it is always difficult to articulate in the written word and points of clarification can get lost.

    However, in the example you give, I would suggest that tissue stress is about reducing the stress to tissues by incorporating some form of process. Root theory attempted to achieve this based on STJ neutral and realigning the foot which does not happen. However, in a number of instances (in many indeed) it achieved it by the nature of the posting altering the forces rather than the position, sufficiently. In the tissue stress approach you are referring to, this employs the SALRE theory utilising the position of the force application in relation to the axis to alter moments. There is a logic to this process and the laws of physics can be used to the explain the theory. Thus it is not tissue stress per se that is the theory, it is the method of altering tissue stress. After all, I could give a patient a rehab programme that reduces the relative stress to the tissue.

    I think we should also acknowledge that, whilst we have sufficent evidence to dispute the STJ neutral concept, we have yet to have any good studies to support the newer concepts.

    Trevor
     
  9. rdp1210

    rdp1210 Active Member

    So Trevor - Do you ever take a mold of the foot? I'm still confused whether TST takes molds of the foot?
    I will be happy to discuss with you at I-FAB why basic Root principles are even more important WITH TST. I will discuss with you how, while Dr. Root never stated so, that his concepts mesh great with material stress theory to optimize getting the forces right. Unfortunately, everyone always talked about the Root rigid orthotic. That device never has existed, all of those acrylic devices he made (we continue to make) are anything but rigid. However by taking the mold with the STJ neutral, we optimize the device so that it starts deforming and putting force against the foot the moment the foot starts deforming from neutral. The device continues to deform with the foot deforming until equilibrium is reached. Each material has a different stress strain curve, and that stress-strain curve varies according to general bending and polar moment of inertia as well as curvature variances. What really is interesting was Dr. Root becoming a great advocate for the Blake device very early in its development. How do the critics of Root explain such?

    What I've been telling people all along is this -- for some strange reason, I had the basic concepts of tissue stress already engrained in me long before any of the current proponents arrived on the scene, so it must have been taught somewhere by the Root disciples. Second is that TST is much more effective when combined with Root concepts (there is no such thing as a single Root theory). It can all fit together as a nice jig-saw puzzle. You will notice that in 1985 I published my first paper on taking more measurements on the STJ than Root proposed (though in talking with him I knew he was contemplating such), and in 1992 I was the first independent person to confirm that Kirby concept was also correct and give more quantification of such as well as discuss the concept of the moving STJ axis. So anyone that somehow pigeon holes me as some sort of antiquated stick-in-the-mud nonprogressive couldn't be further from the truth. I really never consider the name on any concept when using it the clinic. Sometimes I use David Winter's concepts (something I never hear from the TST people) or any number of other people's concepts who have contributed to our understanding. I believe that this whole argument about TST replacing Root is as useless as the blind men each trying to explain the elephant. Each has a part of the truth, but no one is getting the full picture. If we want to discuss any one concept that Root believed or taught, then we can do so.
     
  10. Maybe time to ask my earlier question.

    Anyone have a study saying Roots STJ neutral is in fact STJ neutral?
     
  11. rdp1210

    rdp1210 Active Member

    Interesting question. Reminds me of a discussion I viewed by the great mathematicians and philosophers on what "nothing" is.

    So we first have to know what you mean by the term "neutral joint position" for any joint. What is the neutral position for the hip joint? Why would we choose that point as being neutral? How would we go about proving where the STJ neutral position is?

    If you want to see some interesting data, look at the table of values I posted in my 1983 paper, I listed the STJ neutral position for every subject in the study. What do you make of that data?

    Daryl
     
  12. 1st we would need to take a step back indeed. What is neutral. Neither pronated or supinated was basically the Root definition.

    But at what joint position is that? As in if X-rayed what would be see? And then according to what Kevin wrote on his face book page he was taught 6 different techniques to find neutral what techniques are able to find STJ neutral if at all.

    My major point being if neutral is when the STJ is neither pronated or supinated we have not any proof that a technique is even able to find that.

    If Eric and Kevin's chapter on TST is not peer reviewed and therefore just ideas surely the same standards should be used on Normal and abnormal biomechanics.

    That aside knowing when the STJ was neither pronated or supinated and the position of the STJ axis might be of interest need to mull that over.

    But before moving on Roots neutral needs to be proven to be when the STJ is neither pronated or supinated
     
  13. Jeff Root

    Jeff Root Well-Known Member

    Four weeks ago my wife fell while trail running and dislocated here right shoulder. We just got back from her four week follow-up appointment today. On the wall in the orthopedists office was a poster of shoulder anatomy showing the shoulder in different positions, including neutral. Having done a little google research on shoulder dislocations I see that orthopedists regularly use the terms hypermobility and neutral position in their discussions of shoulder anatomy, function, evaluation and treatment. I don't understand why some podiatrists have such a difficult time with these terms that are in common orthopedic usage throughout the body. Yes, I believe it would be better to have better techniques or to have better standardization of techniques for determining the neutal position of the STJ. However, just as the orthopedist treating my wife, the majority of podiatrists (Simon excluded) need practical techniques and terminology to treat patients today. I suspect the overwhelming majority of DPM's in the world are comfortable with the lack of a more scientific understanding of the neutral position of the STJ because of all of the practical benefits of having it. And I also suspect that they will continue to use the term hypermobility for the same reason.
     
  14. rdp1210

    rdp1210 Active Member

    Please read Lovett and Cotton's paper from 1898 and then let's talk some more. Also let's think in terms of how a neutral position of any joint would correspond to a tissue stress concept. Let's not make this about Dr. Root, but let's think in terms of what any neutral position should be. A basic philosophical difference I have with Eric and Simon is that I believe we really need to have a neutral position. I'm not sure that Kevin has committed himself to either a need or no-need. I realize that it seems like a circular argument, but on the other hand, how does one define Zero except to say that it is a number that is neither positive nor negative. This one question has really perplexed the greatest mathematicians, so who says that we shouldn't feel some degree of anxiety on trying to deal with a definition of neutral. If you want to stretch your mind a little more:

    NOTHING: The Science of Emptiness


    Daryl
     
  15. drhunt1

    drhunt1 Well-Known Member

    Bingo! FINALLY! Doug nails this one. Yes...it's the transverse plane that should be looked at as the major deforming force. For instance, in medial knee arthrosis, the major force is in the transverse plane. While frontal, (coronal), plane contributions can add to the problem, it is the transverse plane at the level of the knee that is the main contributor. Many Podiatric "gurus" have plain missed this, as did the Orthos that forwarded this idea...thus the lateral wedge. While I can fathom why this might work in some patients, the Orthos have pretty much abandoned the idea. Thank you, Doug, for shedding some light on this topic. Here's an animated video I had produced that should be helpful to many here, and my patients really enjoy it:

     
  16. efuller

    efuller MVP

    Daryl, tissue stress uses the concept of partially compensated varus. We do use some root principles. However, by definition, we don't compare a particular foot to an idealized normal. We model the injured part and design a treatment to reduce stress on the injured structure. Therefore, we don't need to use neutral position. You can figure out if someone has a partially compensated varus without doing neutral position measurements.

    Wedging or intrinsic posts are an important and used in tissue stress.

    Daryl what other Root concepts should one use to make tissue stress more effective.


    Daryl, I frequently refer to Winter's ideas on joint power and balance and center of pressure. He wrote a paper with Scott that is essentially the tissue stress approach. In the paper they looked at trying to predict stresses in anatomical structures from external measurements. (Nigg also had a paper on the subject) My thinking on tissue stress came more from these papers than the McPoil paper. Stress in the McPoil paper was essentially plantar pressures. Both Winter and Nigg were looking at stress on specific anatomical structures. Daryl, you may not have heard us say anything about David Winter, but we do talk about his work.

    Daryl, I've been trying to get you to talk about one specific concept that Root has talked about. Is there a problem with precision in neutral position theory that Root and Weed gave three different ways to find neutral position. Why are three different ways needed? Which one definition would you choose if you wanted to do research based on STJ neutral and why would you choose that one?
     
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