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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?
     
  17. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1
    If It Doesn't Work, Why Do We Still Do It? The Continuing Use of Subtalar Joint Neutral Theory in the Face of Overpowering Critical Research
    Paul Harradine, MSc, Lucy Gates, PhD, Catherine Bowen, PhD
    J Orthop Sports Phys Ther 2018;48(3):130–132. doi:10.2519/jospt.2018.0604
     
  18. Trevor Prior

    Trevor Prior Active Member

    Daryl

    Apologies, I was away when you posted this (in the US actually) and have been manic since my return. Yes I do take casts / scans of feet for orthoses. I do not vary these as much as some but essentially it depends on what I am trying to achieve and the mobility of the foot. So, if I have a more mobile foot type and I want to control the medial column (using my surgical principles here), then a corrected impression is taken to allow the device to work within the realms of the mobility of the foot - cast dressing is zero generally. If the arch profile is particulraly low or there is greater soft tissue so the resulting orthoses will be flater than ideal, then we will add in some midtarsal control which is generally applied in the TNJ region. If I have a higher arched or stiffer foot type, then, no correction as the aim is to spread the load across the foot. We know from Cavanaghs work on diabetic feet, to effectively offload a forefoot ulcer, the arch has to start taking load so in the stiifer foot we often want to spread the load. However, we will consider lateral psoting when appropriate or, these days with technology, making the lateral column stiff and the medial column flexible. Occasinally, I will take a pronated impression, when the foot is fixed in eversion / pronation. If we are honest, there is really no evidence that one way or the other is better / worse, correct / wrong, so I work with what seems sensible and, with that old chesnut, what has worked in my experience over the years.

    I recall from one of the first Biomechanics summer schools you describing a way to calculate the orientation of the STJ axis in three planes which always facsinated me but took too long for me to apply in clinic. You also discussed that bisections of the tibia were not demonstrating the tibial angle due to the soft tissue but may be more representative of the mass of the lower limb and thus the effect of force on the foot. These thoughts have stayed with me over the years and were way ahead of the game.

    So, I am going to stick my neck out here and put my spin on neutral position and its worth. When (notice the past tense) I used to take all of the Root et al measures (and I took many over many years), I used to calculate STJ neutral from the range of motion measures. I would use the 1/3 to 2/3 ratio, calculate the position and then recreate that weightbearing - in other words, if the heel was 2 degrees inverted, I would have the patient invert the foot until the heel was 2 degs inverted on the leg and then measure the leg and over rearfoot potion. Invariably, the medial forefoot was way off the ground to achieve this position. It was interesting when I saw patients back over time. I would repeate the measures without looking at my previuous values and the frequency of repeatability (i.e. the same +/- 1 degree) was high so my intra tester relaibility was good albeit the relevance questionable.

    My observations from this were, it was rare that the rearfoot was more than 1-2 degrees inverted on the leg and even rarer for it to be everted. When it was, I checked my measures and assessed for tarsal co-alition it was so rare. Importantly, it was often in line with the leg and, when non weightbearing, if the leg was rotated so that the malleli axis was in plane with the floor, the rearfoot as good as hung in neutral position. That is why I first stopped measuring because I fgured with all the inaccuracies, all I had to do was have the patient stand with the heel more or less in line with the leg and there you go. Thus, the angle of the lower leg is perhaps more important than the position of the rearfoot on the leg with the degree of motion available to compensate for the leg position more important (assuming nothing external to the foot or at the forefoot has an influence).

    I digress. Please, anyone reading this appreciate that all of these thoughts and observations occurred over many years and developed as the research and evidence developed, which has been a slow and tortuous process.

    So, my next thoughts were if equilibrium is the point at which there is no resultant force and thus no movement, when the foot is hanging in 'neurtral' there is no effective stretch or compression on the soft tissues / osseues structures. Thus, if a foot were able to function around this position, there would be reduced stress compared to a more inverted or everted position on weightbearing. I know that ground reaction etc would have a part to play, the ankle would be more dorsiflexed etc., but hopefully you get my drift.

    So, the further away the foot is from that position, the more certain structures will be stressed, thus our interventions that aim to alter the position towards this alignment were designed to reduce the stress etc.

    Now, at best, research has shown us that we can alter the rearfoot position by around 2 degrees which in no way accomodates the positions I used to measure. However, we now appreicate that we can alter the force acting on structures without changing position or a combinatioin of both. Furthermore, as I alluded to previously, in the more mobile foot type, controlling the medial column can be an important factor which in turn, can have a knock on effect to tibial rotation, which in turn will alter stress.

    So, if we consider the neutral position to potentially be the position wherein the tissues have minimal stress (rather than fixated on STJ neutral particularly as clinically we cannot discern between the STJ and ankle), that this will be one factor that will help us discern how much the underlying structure is contributing to abnormal load, that research has shown us that the foot never functions around this position through stance and that our interventions only have a very small influence on alignment, we have a basis for discussion.

    Using structural alignment as part of the prescripton process can be useful (Eric discussed the partially compensated rearfoot varus for instance) particularly if the structural alignment marries the likely increased force for a particular condition (i.e. a flatter foot with tpd) but the control (I cannot make up my mind what the best term to describe what we are attempting to achieve with orthoses should be) etc. that we provide will achieve this in a variety of ways - some alteration in position, alteration in internal moments, sensory feedback etc.

    There are still many unanswered questions which is where we should be focussing our energy rather than the repeated arguments on many forums around STJ netural, tissue stress etc.

    In my opinion, we really have to forge a balanced current thinking that incoporates all of the reasonable (to the best of our knowledge at the moment) concepts, acknowledges what we know from the research and allows us to develop that knowledge to prove or disprove those concepts. Only then will we really move forward because we can educate the younger members and graudates of the profession to then take us forward.

    Trevor
     
  19. Trevor Prior

    Trevor Prior Active Member

    Yes but no but.

    I entirely agree that transverse plane motion is a very significant component in foot an dleg motion and pathology but medial knee OA is a classic scenario of how the research and concepts can mislead.

    to my knowledge, the meta analysis show that the external medial knee adduction motion is increased in medial knee oa, that lateral wedges can reduce this moment but only 67% of patients respond to this intervention. Do I think tibial rotation can be a compnent - absolutely as I have measured it and treated it. However, it is not instead of frontal considerations it is ina ddition to or as an alternative.

    Have a look at thes epaper son athletic groin pain.

    http://bjsm.bmj.com/content/early/2015/11/30/bjsports-2015-094912
    http://bjsm.bmj.com/content/early/2016/10/06/bjsports-2016-096050

    If we exclude training factors / extrinsic factors etc., this clearly demonstrates how there can be more than one pattern of dysfunction that may be associated with a given condition. In my opinion, it has been an error over the years to consider that there is only one pattern of dysfunction for any one condition and this has been our professions problem with the focus on pronation etc. It makes infinite sense that, if we function in three dimensions, there could be at least three patterns for any one condition. Thus for medial knee oa, some may be frontal based, some transverse and what about sagittal? I suspect the latter are those that cannot flex the knee of function in fixed flexion.

    Some research shows that tibial rotation couples with rearfoot motion, others (i.e. Nesters group) that it couples with arch height. Well logically, it probably is individual specific. That is why an appreciation of how the foot functions in the frontal plane (i.e. range of rearfoot motion), transverse plane (change in midfoot width or navicular drift) and sagital plane (navicular drop or change in arch height) allows an assessment of the potential for compensation / motion.

    We need to move away from one pattern per condition.
     
  20. efuller

    efuller MVP

    I really have a problem with title. It works some of the time. The explanation of why it works just doesn't make any sense.
     
  21. efuller

    efuller MVP

    Good point.

    This is one of the few answers I have seen to why a certain position should be chosen for neutral. The problem with this answer is the assumption that stresses are lowest in this position. If you were to tilt the leg there would be a different position at which the foot would just hang. Also the difference in stress from this position and 3 degrees of STJ motion on either side of this position is practically zero. What structures are stressed more with a few more degrees of motion? Tendons and muscles can move and the muscle can rest at a different length. The ligaments are not under stress until the "end of range of motion" is reached.

    The biggest problem here is thinking that the position that stresses are least non weight bearing will be the position that stresses are least when weight bearing. We should not be using the idealized non weight bearing position of joints to determine what treatment should be done in the weight bearing foot.




    The difference between a partially compensated varus and a fully compensated varus is where ground reaction force is. The alignment isn't the problem it is the high lateral forces in the partially compensated varus that are the problem. The partially compensated varus will cause high lateral foot loads with a more lateral position of the center of pressure. This will create high pronation moments with very little stress on the medial column. The goal of treatment is not move the foot to a more normal or ideal position, but to equal out the load across the entire foot.

    The problem is that you can't simultaneously look at forces in a non weight bearing neutral position and treat that as an ideal while examining forces that exist in a weight bearing foot. Trevor, this goes back to your comment "I cannot make up my mind what the best term to describe what we are attempting to achieve with orthoses) If we use tissue stress, we can say exactly what we are trying to do with an orthotic. The neutral position people cannot say what they are trying to do with an orthotic. (Well they can, but the research has shown they can't do what they say they are trying to do.) This is why this debate continues.
    We cannot forge a balanced current thinking because parts of the competing ideas are mutually incompatible. If we are to choose use a neutral position, we should have a better reason than it's the position of least stress when non weight bearing.
     
  22. Trevor Prior

    Trevor Prior Active Member

    Eric, I do not disagree with anything you say above, I was discussing a thought process that I had been through and acknowledged that one had to consider how things changed loading.

    I realised I diod not make my comment on orthses clear (I cannot make up my mind what the best term to describe what we are attempting to achieve with orthoses should be) - what I was referring to here was when we apply a medial or lateral wedge for instance, I cannot make up my mind how to refer to wwhat we are trying to achieve - is this control / wedging / other - we used to say correcting but we know that is not correct?
     
  23. Jeff Root

    Jeff Root Well-Known Member

    In reality we are bracing the foot.

    or·tho·sis
    ôrˈTHōsəs
    noun
    MEDICINE
    1. the correction of disorders of the limbs or spine by use of braces and other devices to correct alignment or provide support.
      • a brace or other such device; orthotic.
    or·thot·ic
    ôrˈTHädik
    adjective
    1. 1.
      relating to orthotics.
    noun
    1. 1.
      an artificial support or brace for the limbs or spine.

    brace
    NOUN

    • 1A device fitted to something, in particular a weak or injured part of the body, to give support.
      ‘a neck brace’
     
  24. Trevor Prior

    Trevor Prior Active Member

    I am specifically referring to the terminology that we could use to describe how waht we are doing to the orthosis (however we do it) could be referred to instaed of correction / control etc.
     
  25. Jeff Root

    Jeff Root Well-Known Member

    We are altering forces with a force altering device (an orthosis).
     
  26. Jeff Root

    Jeff Root Well-Known Member

    Although I sometimes still use the term cast correction, the term cast modification is actually a more appropriate term for what we do to a positive cast or positive digital model of the foot when we manufacture orthoses. An orthosis modifies the interface between the foot and the weight bearing surface of the foot, thereby altering the forces acting on the foot.
     
  27. Griff

    Griff Moderator

    No. That’s not the reality at all in the opinion of body of literature.
     
  28. efuller

    efuller MVP

    How about altering forces and moments. For example, in that partially compensated varus foot we are using a forefoot varus wedge to decrease the force on the fifth met head by increasing the force on the more medial metatarsal heads. This will also shift the center of pressure more medial to decrease the pronation moment from the ground. We are not treating the varus deformity, we are treating high loads on the fifth metatarsal head or we are treating sinus tarsi pain caused by a high pronation moment.

    In the case of pain sub 2nd metatarsal head we are treating high loads there by increasing the loads on metatarsals 1,345 with cork extensions. The point of this example is that we are not always using wedging.
     
  29. Jeff Root

    Jeff Root Well-Known Member

  30. efuller

    efuller MVP

    I agree completely. Where we differ is on the decision making process of the design of the orthosis. I believe it is possible to focus the design of the orthosis on specific anatomical structures. I don't think that an orthosis supports "deformities" found on a non weight bearing exam.
     
  31. efuller

    efuller MVP

  32. Jeff Root

    Jeff Root Well-Known Member

    I don't understand your question.
     
  33. Here is the definition that I gave for foot orthoses over 20 years ago:

    Definition of a Foot Orthosis
    A foot orthosis is a custom fitted, in-shoe medical device which is designed to alter the magnitudes and temporal patterns of the reaction forces acting on the plantar aspect of the foot in order to allow more normal foot and lower extremity function and to decrease pathologic loading forces on the structural components of the foot and lower extremity during weightbearing activities.
    Kevin A. Kirby, 1/7/98

    A foot orthosis is not a "brace". PFOLA's definition of a foot orthosis was already outdated when it was first written and published.
     
  34. I don't really think the title matches the content of the article either. In the article the authors claim "However, despite the issues noted above, the outcome of the use of foot orthoses based broadly on this theory appears positive." Therefore, at least in my eyes, the title should be changed to "It Does Work, That is Why We Do It. Why Subtalar Joint Neutral is Still Used Even Though It is Unreliable, Invalid and Non-Scientific." Now, THAT would have been a much better title and made for a better article.
     
  35. We are not using a brace
    This is what we are doing
     
  36. Griff

    Griff Moderator

    A definition written well over a decade ago... which as Kevin has said, was probably even out of date when it was written.
     
  37. rdp1210

    rdp1210 Active Member

    Eric:

    Maybe you would like to have an up close picture that I took many years ago, before digital cameras, that shows a foot orthosis supporting a very high forefoot valgus. Yes the 5th metatarsal head is not touching the ground. Would that convince you that an orthosis supports a deformity?

    So the argument continues (kind of like the arguments of multiverse vs. universe continue) is there an EROM of the MTJ around the x=0 axis? (refer to my 1992 paper for a definition of the coordinate axis system of the foot). Can the MTJ be stabilized (i.e. in a static stance) with the MTJ in the middle of its frontal plane ROM?

    You have always side-stepped this question as not necessary to know, yet I believe it is critical to know as it is one of the 8 criteria of Root's normalcy. If you can show me it can be done, then I'm willing to cross one of those criteria off my list.

    Daryl
     
  38. Petcu Daniel

    Petcu Daniel Active Member

    Next to the very practical and precise definitions of Anthony and Kirby it can be added some other helpful referenced definitions:

    "Orthoses or orthotic devices are externally applied devices used to modify the structural and functional characteristics of the neuromuscular and skeletal systems".
    ISO 8549-1:1989(en) Prosthetics and orthotics — Vocabulary — Part 1: General terms for external limb prostheses and external orthoses, https://www.iso.org/obp/ui/#iso:std:iso:8549:-1:ed-1:v1:en

    "Lower limb orthoses - Orthoses designed to modify the structural and functional characteristics of the neuromusculoskeletal systems of the lower limb: the devices may be custom fabricated or prefabricated; the prefabricated devices may be adjustable or ready to use"
    "Foot orthoses - Orthoses that encompass the whole or part of the foot. Included are,e.g orthopaedic shoes, insoles, shoe inserts, pads, arch supports, heel cushions, heel cups, orthopaedic inlays""
    ISO 9999:2011(en) Assistive products for persons with disability — Classification and terminology,

    The question is how is acting to modify "the structural and functional characteristics of the neuromuscular and skeletal systems?" And I think an answer comes from Kirby's definition even in my opinion a limitation of this definition is the identifying of the foot orthosis only to the "in-shoe" devices. Medical footwear is a foot orhoses (as above mentioned definitions is suggesting)!

    Daniel
     
  39. Petcu Daniel

    Petcu Daniel Active Member

    And another very recent definition from FINAL DMEPOS Quality Standards Effective: January 9, 2018

    "Orthotic Devices: Rigid and semi-rigid devices used for the purpose of supporting a weak or deformed body member or restricting or eliminating motion in a diseased or injured part of the body."

    https://www.cms.gov/Research-Statis...l-DMEPOS-Quality-Standards-Eff-01-09-2018.pdf

    Maybe this is too general definition!
    Daniel
    :confused::confused::confused:
     
  40. Jeff Root

    Jeff Root Well-Known Member

    A foot orthosis does not need to be custom fitted. So this aspect of the definition is wrong and demonstrates bias. Secondly, while your intent may be to alter magnitudes and temporal patterns, these are not being measured so the definition suggests you are doing something clinically that you can't prove. Thirdly, how can an foot orthosis alter magnitudes and temporal patterns without supporting or bracing the foot or a part of the foot?

    Kevin is describing what a foot orthosis does, not what it is. This is an important distinction. The definition does not need to be complex. It should simply describe WHAT the device is. The PFOLA definition does this.
     
    Last edited: Mar 2, 2018
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