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The Diagnostic Value of Pedobarography

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Dec 3, 2014.

  1. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
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    The Diagnostic Value of Pedobarography.
    Choi YR, Lee HS, Kim DE, Lee DH, Kim JM, Ahn JY.
    Orthopedics. 2014 Dec 1;37(12):e1063-e1067. doi: 10.3928/01477447-20141124-52.
     
  2. Dennis Kiper

    Dennis Kiper Well-Known Member

    There are two problems with this paper. First, the use of the pedobarograph should be used to identify the function of the planes of motion rather than a diagnosis. Quantifying pressure of the biomechanical ROM is not “abnormal” pressure but rather the result of “overpronation” which is perfectly normal.

    Second, current orthotic technology does not reveal an accurate modification of pronatory and weight bearing forces thru the gait cycle, because it is inaccurate and in many cases distorts the planes of motion thru the gait cycle.
     
  3. Griff

    Griff Moderator

    And how would one use pedobarography to "identify the function of planes of motion" Dennis?
     
  4. Dennis Kiper

    Dennis Kiper Well-Known Member

    By comparing a barefoot test with the same barefoot test with orthotic support. This of course is dependent on the use of an accurate orthotic technology.
     
  5. Dennis Kiper

    Dennis Kiper Well-Known Member

    Let me re-phrase my statement:

    with an accurate, quantifiable orthotic technology
     
  6. Griff

    Griff Moderator

    Still viewing the world through your kinematic tinted lenses then...

    How do you perform a barefoot test with orthoses??
     
  7. Dennis Kiper

    Dennis Kiper Well-Known Member

    Obviously, you have no experience using dynamic pedobarograhic systems. I've been utilizing them for over 20 years.

    Try reading my article inPodiatry Today. Then, instead of accusing me of seeing thru tinted lenses you might learn something.
     
  8. Griff

    Griff Moderator

    Do you have 20 years experience, or 1 years experience which you have repeated 20 times?

    I have learnt a lot from your posts on the arena Dennis.

    That's probably not to be taken a compliment though...
     
  9. Dennis Kiper

    Dennis Kiper Well-Known Member

    You haven't learned anything. If you'd read the article you would find your answers.

    I suppose you're too swamped in corns and calluses to understand the biomechanical function behind your palliative expertise.
     
  10. Griff

    Griff Moderator

    The best thing about rhetorical questions is that they seldom need answers Dennis.
     
  11. efuller

    efuller MVP

    Dennis, if you want us to understand your point of view you could cut and paste from your article to answer a question. Or, you could provide a link to your article. Of course, if you didn't think your test would stand up to scrutiny you could avoid questions and belittle the people who ask them.

    Eric
     
  12. Dennis Kiper

    Dennis Kiper Well-Known Member

    Because the technology I use is so different from what the rest of the profession is using, perhaps terms like “biomechanical stability” does need further clarification. Here is the link to my article:

    http://www.podiatrytoday.com/closer-look-principles-fluid-dynamics-they-relate-orthoses

    It will answer that question, as well as how to do a gait analysis scan barefoot with orthotic support, the technological defects of a traditional orthotic and why I referred to your predictability rates as 50/50.

    I'm aware that you personally have had experience with this technology and knew Marty Krinski as well. Unfortunately he presented this technology before he was able to explain it better. I hope I've done a better job.

    If you still have a question or want further clarification about anything, I'd be more than happy to discuss it with you Eric.
     
  13. efuller

    efuller MVP

    The only place in the article where I saw a definition of stability was what I quoted below. Is this your definition of biomechanical stability?

    Here on the arena we have been debunking the idea of a locked joint for many years. Dennis is your idea of stability the same as locking? If not what is it?



    site 3 was
    I don't think the paper you site supports your idea. Could you explain further? What is primary stability and secondary stability? What do you mean by loading of the Midtarsal joint?

    Eric
     
  14. Dennis Kiper

    Dennis Kiper Well-Known Member

    The only place in the article where I saw a definition of stability was what I quoted below. Is this your definition of biomechanical stability?

    Biomechanical stability is functional and dynamic, it certainly is not “locking”: “At midstance, hydro-dynamic pressure loads and self-posts*the midfoot and forefoot*to an equilibrium state of*stability (7), concurrent with the STJ optimal position.”

    it means that the joint or joints need to function in their closest congruous state as possible so that wt bearing and pronatory forces are minimized to cause the least amount of destabilization and subluxation to the lower extremity (by subluxation, I'm referring to deviation of the joint axis and instability)

    I don't think the paper you site supports your idea. Could you explain further? What is primary stability and secondary stability? What do you mean by loading of the Midtarsal joint?

    Then do you think the ROM at the STJ is greater than the ROM of the TNJ? (I remember learning that the TNJ had the greatest ROM in the foot, back in '67) Prim stability and second stability refers to midfoot control, primarily over rear foot control, secondarily.


    If you control the rear foot first and if what I remember learning and the paper is correct that the ROM at the TNJ is greater, at midstance you would have a moment of instability at the TNJ, this would allow a transference of additional pronation to the STJ when it should be stable (“neutral” as it were for the sake of explanation ) then you have destabilization, because pronation movement has a retrograde effect that occurs in all 3 segments (forefoot-midfoot-rearfoot)--I didn't give credit to Dr Root for this statement, but it was he who stated it, it may even be listed in the “Compendium of Biomechanics”

    If you control the midfoot first, then the rear foot is as I stated “already limited”.


    What do you mean by loading of the Midtarsal joint?

    I thought my article was clear about the “loading” of the rearfoot, midfoot and forefoot, maybe my clarification of loading just the MTJ will be better.

    As fluid is being displaced further into the arch chamber and the dynamic motion of the biomechanical cycle is decelerating, the fluid is moving and filling up to meet the plantar surface of the MTJ. This is the “loading phase”, once, all the fluid has filled the arch chamber and the foot cannot pronate any further due to hydro-dynamic pressure, considering the fluid is locked in by the rearfoot, lateral column, forefoot and medial side of the polyurethane container (refer to Archimedes Principle and the hydrodynamic effect—if you have any questions about this, please consult a physicist, I'm only capable of applying the principles), it has reached an “equilibrium state” confirmed by
    Dr. William A. Taylor
    Emeritus Professor of Physics
    Department of Physics and Astronomy
    California State University, Los Angeles

    such that the forces within the arch chamber are equal and the structure of the foot is in a congruous or near conguous state as well (the degree of accuracy is dependent on the accuracy of the volume of fluid).
    Now, the MTJ is “loaded”

    I believe a good representation of this is demonstrated at: http://drkiper.com/animation.html

    Eric, what did you make of the pedobarographic reading presented in the article?

    This was from my first “Dynamic Pedobarograh” in 1991, the 2nd scan I referred you to was from a Tek Scan system, I don't recall the year.

    How do you define “loading of the MTJ? Can you help me envision what you see?


    Dennis
     
  15. efuller

    efuller MVP

    In your article you equated stability with locking. Now, you are saying that it is not locking. I don't see the connection you seem to be making between stability and hydro dynamic loads.

    On the other thread you defined biomechanical stability something like there was even pressure under all locations of the foot. Stability seems to be the wrong term for that concept. I would agree that the ideal load on all metatarsal heads should be close equal. However, this is just one anatomical structure. Having the load on all metatarsal heads being equal does not mean some other anatomical structure is not excessive. For example, a foot with a laterally positioned STJ axis may tend to roll into supination and more load would be placed on the lateral metatarsals. The peroneous brevis muscle would have to constantly contract to get closer to even force on all metatarsal heads. A silcon orthotic could deflate laterally and inflate medial pushing the foot further into supination. It that situation the peroneal muscles would have to work even harder.

    Joint congruity is just something someone just made up without actually measuring if it was important or even a useful concept in all situations. Why can't a joint function, without damage, or excessive stress, when the joints are not in maximum contact?

    Anyway there is no connection between what you are calling stability and joint congruity.




    Dennis, this is a problem I have with a lot of your writing. You use undefined terms. Then you string together a bunch of undefined terms that give it a sense of truthiness when in fact there is no meaning.

    The first paragraph directly above you define stability in terms of control. Neither of those terms is defined.

    The paper that we were discussing: Lundgren P, Nester C, Liu A, Arndt A, Jones R, Stacoff A, Wolf P, Lundberg A. Invasive in vivo measurement of rear-, mid- and forefoot motion during walking. Gait Posture. 2008; 28(1):93-100. I don't recall that paper mentioning anything about limitation of motion. It did discuss axes of motion. The other stuff you say, directly above, seems more out of Root Orien and Weed and that is not supported by that paper. Root et al. also use the term stability without really defining it. Well they sort of define it as a normal joint does not move when it supposed to not move. The problem is the definition of normal. They chose an arbitrary normal. Why should we accept their definition.



    You talked about loading the plantar surface of the MTJ. A silcon orthotic is not really going to load the plantar surface of the MTJ because there is a lot of soft tissue between the skin and the bones that make up the midtarsal joint.

    You describe how pronation is prevented by the rearfoot, forefoot and lateral column and the bag "locking" and the pressure in the bag prevents further pronation. It is certainly possible for the arch lowering of pronation to be forceful enough to lift the lateral column.

    Looking at the "barefoot test". You did use a mat and not an in shoe sensor right? Of course you are not going to see pressure between the rigid orthotic and foot when you use a mat. What are you concluding from that roll over process? You cannot be concluding that there is more pressure applied by the arch of the orthotic to the foot. You could say that there is more force applied to the ground by the silicon orthotic under the arch of the foot, but that is not anything that is important.

    More on MTJ loads later

    Eric
     
  16. Dennis Kiper

    Dennis Kiper Well-Known Member

    In your article you equated stability with locking. Now, you are saying that it is not locking.


    Eric, the term “locking” is how you and I learned it in school. I stated I'm interchanging the term locking for stability in the event there are others out there that either still use the term “locking” for the purposes of stability or require it to understand the concept of stability.

    I don't see the connection you seem to be making between stability and hydro dynamic loads.

    A hydro-dynamic load is incompressable, therefore wt bearing and pronatory forces would be stable throughout the biomechanical cycle as compared to a static load/fixed position.

    “**Now, the transference of the forward momentum and sagittal force on the foot coupled with the weightbearing and pronatory forces of the midtarsal joint complex against the position and surface of the orthosis (referring to a traditional orthosis) at the end of midstance, disengages the metatarsophalangeal joint (MPJ) complex, just enough to allow for forefoot pronation, through the casted orthotic position. -

    I am talking about the moment (around midstance) where the leg is just pre-vertical to post-vertical. The plantar surface of the foot during this time with a trad orth has stopped, the intrinsic momentum of the foot is what is unstable (**This last phase of intrinsic pronation at the forefoot continues through the moment of heel-off under the weightbearing and pronatory forces of the midtarsal joint complex and destabilizes to increase the flexibility of the foot’s structure. Considering that pronation movement has a retrograde effect that occurs in all three segments (forefoot/midfoot/rearfoot), if any segment even partially unlocks or destabilizes”) -
    With the hydro dynamic platform, the fluid is in constant motion (throughout the biomechanical cycle) loading the intrinsic structure. The plantar surface of the foot does not stop during this same time secondary to the hydro dynamic motion.


    On the other thread you defined biomechanical stability something like there was even pressure under all locations of the foot.

    I'm not saying there is “equal pressure under all locations of the foot”--I stated that the pressure within the containment is equal throughout. That's is what I referred to as an “equilibrium state”, confirmed by my patient and physicist Dr Taylor.


    Having the load on all metatarsal heads being equal does not mean some other anatomical structure is not excessive----


    I don't understand your thinking here. First—why do you say that the load somewhere else is “excessive”--it may be different, that doesn't make it excessive (although this point could be argued, that all forces are excessive—which is true to a point). Part of the hydro dynamic effect does equalize pressure at times in one area in order to reduce higher (excessive) pressures from other areas. That's the beauty of this science.

    A silcon orthotic could deflate laterally and inflate medial pushing the foot further into supination

    This is incorrect.

    “**Computerized gait tests with the silicone dynamic orthotic show that the forces under the MTJ complex measured by the ground reaction forces are less than the combined ground reaction force of the heel, lateral column and forefoot together. Increasing or decreasing the load under the tarsus has a direct correlation with the biomechanical loading measured in ground reaction force. As a result, this forces the fluid under the entire tarsus and forefoot (proximal to contact), and the fluid is not displaced laterally under weightbearing and pronatory forces.”

    Besides, IF the silicone were to “deflate” laterally, it wouldn't inflate medially, it would raise the lateral column, BUT it doesn't work that way.

    Joint congruity is just something someone just made up without actually measuring if it was important or even a useful concept in all situations. there is no connection between what you are calling stability and joint congruity.

    Geometrical congruity is the epitome of efficiency. As a scientist, you have to be able to extrapolate that kind of information. I don't feel you can properly evaluate the pedobarographic and tek scans. I've had the opportunity to read a couple thousand of them at least with barefoot and orthotic assisted (traditional orth and fluid) readings. The technology is there. It's accurate.
    It can help us visualize the biomechanical function of the stance phase of the gait cycle.
    Even a barefoot scan reveals a pronator/supinator, hypermobility and rigidity.


    You can try and make the argument of mat scan and in shoe measurements, but I would argue that Newton's 3rd law of physics and the fluid medium represents an accurate picture of biomechanical function. And because of that we can see the function of the STJ, MTJ and forefoot. If there was a gap in GRF under the tarsus, that would indicate to me a need for a Rx/volume adjustment. You said it's not important to see that, I would say the same thing if I was defending traditional technology. You just haven't seen enough scans. Even if you did, you can't make the adjustments that would quantify the results I can.

    If you're going to be the biomechanical expert of the foot, you need to see the entire structure and functioning of all its segments. With a traditional orthotic, heel impact probably isn't important to be able to see either, but with fluid technology, I can see the dampening effect of heel contact compared to the barefoot scan and I can see and measure the deceleration of pronation at heel contact which allows me to assess STJ loading. I suppose you're going to say, because you can't do that with a trad orth, that's not important either????

    Why can't a joint function, without damage, or excessive stress, when the joints are not in maximum contact?

    Wear and tear is a fact of life, especially in human tissue. Even congrous joint function results in damage (over time). You may not agree, but as I stated in another thread, all forces are pathologic over time. You can't eliminate them, only minimize and reduce them. The more accurate the congruity the greater the efficiency of joint function. This trickles down to greater biomechanical efficiency and performance with less tissue stress.

    It is certainly possible for the arch lowering of pronation to be forceful enough to lift the lateral column.

    What experiences have you had, that you are so certain of this? Perhaps, you had instability with a pair you tried on an uneven surface, but on a level surface, walking, running straight ahead, with a correct or underloaded Rx, this is incorrect.
    Only if the fluid volume is overcorrected (too much) but, one would either recognize that clinically/and what you'd expect biomechanically by the patient's comments or you'd see that distortion if looking at a pressure scan.--Otherwise, no. Pronatory forces are not powerful enough to overcome a proper fluid load.


    You talked about loading the plantar surface of the MTJ. A silcon orthotic is not really going to load the plantar surface of the MTJ because there is a lot of soft tissue between the skin and the bones that make up the midtarsal joint.


    This would be like my saying, when you step on a traditional orthotic only the skin bends????


    Of course you are not going to see pressure between the rigid orthotic and foot when you use a mat. ---but that is not anything that is important.


    But, you can see the biomechanical function of the forefoot loading before and after midstance, and that's a lot of information. I don't know why you think that's “not important”--it can show hypermobility of a segment. I think in some cases that can be important.


    The real bottom line is this technology works. It's evidenced by gait analysis systems. It's quantifiable, and makes it a true Rx. Right now, shoe salesmen and their mothers can make traditional orthotics.
    They can't make what I make.

    The hydrodynamic platform effects all three planes of motion “simultaneously” each and every time you adjust the fluid volume. You're adjustments are in degrees, my adjustments are capable of hundredths of a degree.--Furthermore, static adjustments of posts can distort the planes of motion and congruity.
     
  17. efuller

    efuller MVP

    Dennis, you are really hard to pin down. You use the word stability a lot. What do you think the word means. How do you measure stability?



    Dennis, in your article you described how when you walk the heel hits the ground and this compresses the fluid under the heel toward the forefoot. Then after heel off the fluid is compressed to move it back under the heel for the next step. Now your are saying that the fluid is not compressable. Care to explain.





    Why do you think my statement is incorrect. John Weed used to teach the exam technique where you would try and place your fingers under various parts of the foot. There are some feet with very little force under the lateral forefoot. You can easily lift them with your fingers. Fluid in a sack can easily lift the lateral forefoot in this feet. Pressure under the medial arch will increase with pronation and this will inflate the bag under the lateral column.


    As a scientist you should verify your assumptions. You are assuming that joint congruity is better without any confirmation.

    Regardless, You are still not making any connection between joint congruity and pressure readings from a techscan mat. What do you think is the connection?

    Dennis, why do you think I can't properly evaluate a tek scan roll over process?

    Dennis, I don't think you can properly evaluate a pressure distribution map because of what you said in your article. See below.

    Dennis, you cannot measure the speed of pronation with a force platform. There is the concept of touchdown angle. People will change the angle of their foot to the ground at heel contact (both sagittal and frontal planes) in response to varying conditions. The only way you could measure pronation velocity with a force platform is compare the time of lateral forefoot contact to time of medial forefoot contact. Angular velocity is the number of degrees moved in a certain time period. You cannot calculate the velocity if you do not know the number of degrees of motion. This is why you cannot calculate velocity. This is one reason that I believe you do not understand what you are seeing when you evaluate a pressure distribution during gait.

    Dennis, you appear to have an over reliance on pressure analysis. Yes, there is some good information there. However, motion analysis and a force platform and inverse dynamics you can get a much better picture of what's going on when compared to a force platform alone. It all depends on what your research question is.



    Dennis, my point was that you could have a joint that is not congruous a still not get pathology. Yes, there will be more stress if there is less contact. However, is that stress high enough to cause pathology. To function we need to move our joints away from the position where there is the most contact. That's ok if that movement does not lead to excessive stress.

    You also seem to be conflating joint congruency with function of the entire foot. If one joint surface is not congruent, that may not have any relation to stress on structures that are not part of that joint.




    Neither a traditional orthotic or a silicon orthotic contact the bones of the midtarsal joint because there is soft tissue between the orthotics and the bones. Orthotics that try to move the bones of the MTJ by pressing up in the arch can be quite painful.


    The entire quote was
    Dennis, you missed my point entirely. Have you ever used an inshoe sensor? One of the big reasons that I don't think you understand rollover procecess analysis is the picture you showed in your article of the difference between a pressure mat analysis of the silicon orthosis and a posted rigid orthosis. Do you realize that pressure sensors on top of the orthoses would have given an entirely different analysis? Do you realize that the forces applied to the foot by the orthosis are more important than forces applied to the ground by the orthosis? If you did understand these differences, the picture in your article is incredibily missleading. I'm just hoping that you just don't understand rather than you are intentionally trying to mislead people.

    Eric
     
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