Welcome to the Podiatry Arena forums

You are currently viewing our podiatry forum as a guest which gives you limited access to view all podiatry discussions and access our other features. By joining our free global community of Podiatrists and other interested foot health care professionals you will have access to post podiatry topics (answer and ask questions), communicate privately with other members, upload content, view attachments, receive a weekly email update of new discussions, access other special features. Registered users do not get displayed the advertisements in posted messages. Registration is fast, simple and absolutely free so please, join our global Podiatry community today!

  1. Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
Dismiss Notice
Have you considered the Clinical Biomechanics Boot Camp Online, for taking it to the next level? See here for more.
Dismiss Notice
Have you liked us on Facebook to get our updates? Please do. Click here for our Facebook page.
Dismiss Notice
Do you get the weekly newsletter that Podiatry Arena sends out to update everybody? If not, click here to organise this.

Prescribing Orthoses: Has Tissue Stress Theory Supplanted Root Theory?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Kevin Kirby, Apr 1, 2015.

Thread Status:
Not open for further replies.
  1. drhunt1

    drhunt1 Well-Known Member

    Daniel-answer is.......no. Instead of adding to the work that Root began, many are trying to reinvent the wheel. Expansion of the work that Root, et all., began is what we should be achieving, IMO, not trying to focus on "pathology specific" biomechanics solutions. Looking at the big picture is the direction I think we need to go, and focusing one's attention on specific problems misses that opportunity.
     
  2. efuller

    efuller MVP

    Jeff, you certainly showed that some thought went into the stress on anatomical structures when Root, Orien, and Weed wrote the book. The problem I have is the disconnection between the pathology and the prescription writing protocol. John Weed's lecture syllabus is the only place that I have seen a protocol for writing a prescription under the neutral position theory. Weed's protocol relied on heel bisections and forefoot to rearfoot relationships. There is very little connection between those measurements and pathology. For example, you could get the same measurement for someone who had no pathology, PT dysfunction, or Hallux valgus. Should those three things get the same orthotic? This is the area that I am referring to when I say that neutral position theory does not pay attention stress on anatomical structures. In addition to the fact that those measurements cannot be done reliably, there is the problem of connection of those measurements to pathology. Finally, why should treatment of those measurements (heel bisections and forefoot to rearfoot relationship) be helpful for various pathologies. Especially when you consider that the forefoot to rearfoot relationship is done in neutral position and that measurement changes when the STJ is more pronated and the vast majority of feet don't stand in neutral position on or off of the orthotic made from a neutral position cast.

    So, there are definitely, problems with the one "published" neutral position prescription writing protocol.

    Reading the above you can see how many students came away with the mantra pronation bad, supination good. When you look at STJ equilibrium, you can see that it is possible to have both over pronators and over supinators. It should be ok to try and pronated the over supinators. How do you fit that idea into neutral position theory? You have a foot that is pronated from neutral position and is laterally unstable with peroneal tendonitis. Do you want to move that foot toward neutral position or do you want to increase pronation moment acting on the foot. Jeff has said he has no problem making orthotics with lateral heel skive. So, how do you reconcile the belief that orthotics work by pushing the foot toward neutral positon with the use of a lateral heel skive. Intellectually, something has to give.

    So, if we want to improve upon what Root et al did, one choice is moving away from the idea that the foot will function better when we push it toward neutral position. Can abandoning neutral position be consistent with neutral position theory? Do we have to call it something else? Tissue stress?

    Eric
     
  3. Petcu Daniel

    Petcu Daniel Well-Known Member

    Raymond Anthony's book : "The Manufacture and use of the functional foot orthotics", Krager, 1991 is based on the same protocol

    Daniel
     
  4. Jeff Root

    Jeff Root Well-Known Member

    I could just as easily criticize Tissue Stress theory prescription protocol by saying that if you have an asymptomatic foot that is highly pronated or has HAV or some other positional or structural issue, you have no justification for treatment since you don't rely on measurements, position, structure, joint ROM, only symptoms and symptom location. Hence, in Tissue Stress Theory, there is no justification for treatment of the asymptomatic foot. The ideal use of biomechanics is prevention, not the treatment of symptoms or deformity once they occur.

    There is no question that how we describe symptoms and treat pathology has changed since the days of Root and Weed's teaching. We have been using alternative treatment theories and concepts for a long time in conjunction with many of the concepts that Root and Weed taught. For example, rather than correcting the heel to vertical, many of the orthoses that we manufacture at Root Lab are corrected with the heel in some degree of inversion. This became very popular starting back in the 1980's after the Blake orthosis was introduced. Many practitioners decided that they wanted to increase STJ supination moments with their orthoses but they didn't want to use a Blake type orthosis to do this. So they began inverting the heel anywhere from a few degrees to in excess of 10 degrees. This is not the original Root/Weed prescription protocol but it was being done long before McPoil popularized the term tissue stress. Why, because it was deemed to be a technique that reduced STJ pronation (moments).

    As I quoted from Normal and Abnormal Function of the Foot, Root et al recognized that the foot was a more stable structure when the STJ was in a neutral or slightly supinated position at the STJ and that the pronated foot was less stable. So, many of todays orthotic prescriptions are very consistent with this objective. Heel bisection and FF to RF measurements are just one aspect of the orthotic prescription protocol. Most orthotic labs use heel position and FF to RF correction angles when determining how to manufacture their orthoses. So I think the application of these speaks to their value in the treatment process.

    Brian Stoodly, the owner of a Canadian orthotic lab did a presentation of data at the PAC/PFOLA conference of their labs two year study evaluating orthotic returns. Ninety six percent of the orthoses returned for adjustment were casted with impression foam and only four percent were casted using plaster suspension casting. STJ and FF to RF position can be controlled much more accurately using plaster suspension casting than they can with impression foam. What does this data tell us about preferred technique?

    I would simply call it foot orthotic intervention, which can be adapted and modified as needed as new information becomes available. I'm heading out in a few minutes for a day quad riding, so this is my last post for now. Have a good day!

    Jeff
     
  5. efuller

    efuller MVP

    Actually, in my last post I suggested STJ axis position as a possible measurement that could be used in the asymptomatic foot. If you have an extremely medially deviated STJ axis you would use a medial heel skive. If you have an extremely laterally devaited STJ axis you would use a lateral heel skive. I also mentioned looking at the sock liner of the shoe and if a deep impression was noted under the hallux (indicating limited 1st MPJ motion during gait). If you saw that impression, you could design an orthotic that would decrease stress on the first ray. So, there are measurements and observations, that can be theoretically linked to future pathology.



    I haven't been able to find my copy of Normal and Abnormal function of the foot. I recall somewhere a discussion of stability that looked at heel and leg bisections. I'm pretty sure this in either vol 1 or vol. 2. The theory went the foot and leg were looked at in the frontal plane and stability occurred when the heel bisection and the leg bisection were both vertical. Instability occurred when the heel bisection was either inverted or everted to the point where body weight and ground reactive force were not pointed directly at each other. When the heel was inverted there would be supination instability and with the heel everted there would be pronation instability. This was the rationale for the cause of joint instability related to heel bisection. Jeff, what you describe above makes logical sense when you just look at pronation instability and you make the assumption that the normal foot will have a vertical heel when the STJ is in neutral position. That logic falls apart when you actually look at real people in terms of where their heel bisection sits and where their STJ is within its range of motion when resting. There is also a flaw in that logic as it ignores the influence of the forefoot. (Yes, the forefoot is added in later, but not very well. This is where you get the confusion caused by the question: does the forefoot control the rearfoot or does the rearfoot control the forefoot.) Within neutral position theory there is some confusion between reality and what ideal should be and the concepts of neutral and vertical. If someone is going to respond to the above points, I would like them to also make the case for the importance of neutral position. What are the historical reasons for choosing neutral position for being so neutral? If neutral is supposed to be stable, why do so many people have markedly inverted heel bisections when standing in STJ neutral? Why do so many people have their medial forefoot off of the ground in STJ netural?

    So, the above flaw in logic can be solved with a better understanding of how ground reaction force causes motion about the STJ axis. Enter center of pressure and STJ axis location. The combined forces from the forefoot and rearfoot can be summed together and examined for their relationship to the axis to determine what the ground will attempt to do the foot. So, using center of pressure and STJ axis you can get away from the confusion caused by the concepts of neutral position and stability of the foot.

    For those that have been complaining that STJ axis rotational equilibrium (SALRE) is just reinventing the wheel. Tissue stress and SALRE are an obvious improvement to some of the confusion created by the earlier simplistic and confused explanations of what causes pronation.

    Eric
     
  6. Rob Kidd

    Rob Kidd Well-Known Member

    I gave my copy of Root 2 to the school of podiatry in Johannesburg - they could not afford one. Since I had essentially given up practice it seemed the right thing to do.
     
  7. Jeff,
    Asymptomatic HAV could and by me anyway be a reason to use foot orthotics if I detect that tension in the plantar soft tissue is adding to the deformity.

    Erics plantarfascia article explains the mechanics.

    but the asymptomatic symptomatic orthotics discussion is a mind field but to say using tissue stress you would not treat deformity such as HAV wear I sit is not correct, but I am much more careful in using a asymptomatic patient than I was when I first started practice using a bastardised version of Root.

    The issue of course is what the device is adding stress too when being warn, and therefore what potential injury may occur.

    ie medial knee OA
     
  8. Jeff Root

    Jeff Root Well-Known Member

    Eric,

    Take a close look at the drawings and related captions on pages 44, 45 and 78 of Normal and Abnormal Function of the Foot (see attached pdf). The authors discuss how the forefoot (MTJ) influences STJ pronation moments, center of pressure and the lever arm acting on the STJ. Notice how line AB in figure 2-8 looks like the drawing of a medially deviated STJ axis. The authors aren't saying that the foot is stable because the heel is vertical or because the STJ is in neutral, they are saying that rearfoot adduction (or forefoot abduction) make the foot less table because it increases STJ pronation moments. And please note the following sentence on page 78:
    Jeff
     

    Attached Files:

  9. I cringed when I read the first sentence from the first caption from the excerpt you provided from "Normal and Abnormal":

    Jeff, do you have a single reference that you know of that supports this statement from "Normal and Abnormal" other than the anecdotal observations and unsupported hypotheses of the authors?
     
  10. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    They were talking about the foot that demonstrates and increased range of transverse motion at the MTJ. There are inherent differences in the range and direction of motion at the MTJ between subjects and this increased transverse motion is clearly evident during an open chain examination of the MTJ. I demonstrated this in the recent video I posted on the PA. The question in my mind is, why is there so little attention focused on axial differences at the MTJ at a time there is so much focus on axial differences at the STJ?

    Jeff
     
  11. The reason that we don't focus on "axial differences in the midtarsal joint" is because there is no such thing as the oblique midtarsal joint axis and no such thing as the longitudinal midtarsal joint axis. Manipulating the foot with your hands to produce the motion you want to see does not necessarily mean anything scientifically or functionally.

    Now, back to my question: do you have a single reference that you know of that supports this statement from "Normal and Abnormal" other than the anecdotal observations and unsupported hypotheses of the authors? I think I know the answer.

    Unfortunately, "Normal and Abnormal" is full of such statements that are nothing other than anecdotal observations and hypotheses made by the authors that have not a shred of scientific evidence to back up their hypotheses. In addition, many of the biomechanical explanations made in "Normal and Abnormal" do not make sense in today's day and age of modern biomechanics theory, including the passages you just posted up here on Podiatry Arena.

    However, that being said, for a 38 year old book, it is still a good one with much valuable information, in my opinion.
     
  12. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    Merton Root never wrote about his midtarsal joint examination technique. He taught it and he lectured about it, but he never wrote about it to the best of my knowledge. Unfortunately it remains one of the best kept secrets of his work. If you haven't examined the MTJ like he did, and if you have you not felt what I'm talking about I think you are missing out on one of the best clinical examination techniques available. If produces tremendous insight about the function of the MTJ.

    Have you ever done an open chain examination on an ankle joint that demonstrated increased triplane motion? If so, doesn't this tell you something clinically significant about that individuals ankle joint "axis"? When we do an open chain examination of both the range and direction of motion of a joint, the clinician draws upon their experience in comparing the direction of motion, range of motion and quality of motion to that of other subjects they have examined. This clinical observation and feel provides feedback that can be used in helping to understand foot function and can be applied in the prescription writing process.

    I have a fairly rigid MTJ. I have often had practitioners examine a subjects MTJ and then had them examine my MTJ. They get it once I show them the basic technique and then have them practice it on different types of MTJ's. I realize there is no oblique and longitudinal MTJ axis. However, different patients demonstrate significant differences in their range and direction of motion at the MTJ. If the subject demonstrates relatively more ad/abducution at their MTJ, we know the axis of motion is more vertically oriented than the subject who doesn't demonstrate this same motion. Just like the video you posted of your daughter-in-law, not everyone demonstrates this motion. Is that clinically useful? I would say yes, extremely.

    Jeff
     
  13. Jeff:

    I learned the technique for examining the midtarsal joint from John Weed when I was a 2nd year podiatry student over 30 years ago and saw your father demonstrate it numerous times at his lectures. I even taught the technique to my podiatry students when I was a Biomechanics Fellow at CCPM. So, I am well aware of the technique you are talking about.

    That being said, since then I have learned more about biomechanics. What I learned it that forcing the forefoot to move relative to the rearfoot in a certain direction with an external force from your hands and what happens during gait with the axis of motion of the midtarsal joint are two totally different things (thank you Nester et al). The "axis of motion" Mert Root and John Weed thought he was finding and taught all of us to perform may or may not have anything to to with production of pathology as the authors of "Normal and Abnormal" suggest.

    Maybe you can list some research to support your conjecture that your father's MTJ examination technique is predictive of anything. If not, then I will assume it is another of their unsupported hypotheses that have no research evidence to back them up.
     
  14. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    Given that I have never seen anyone else other than Mert, John Weed and maybe a hand full of other practitioners use this technique properly (most don't isolate MTJ motion), how would anyone even begin to consider researching the benefit of it? The fact that there is no research doesn't mean that the technique isn't clinically useful. I previously went to the effort of videoing and posting this technique on the PA so that objective individuals on the PA can determine the benefit of this examination technique for themselves.

    Jeff
     
  15. Jeff:

    You are the one who said:

    As I stated previously, John Weed taught me personally how to perform the technique and I taught it over a 100 times during my Biomechanics Fellowship, so I know what you are talking about. If you don't have any research evidence for this technique's benefit, then please explain to me, and those others following along, how this "one of the best clinical examination technique available" will increase our ability to understand how the midtarsal joint functions during weightbearing activities. I gave up on doing the technique years ago since I didn't find it helped me understand the patient's pathology or foot function at all.

    For example, how does it account for the multiaxial moving MTJ axis that Nester et al has shown to be the case in his walking studies or for the multiaxial moving MTJ axis shown by Van Langelaan in his weightbearing cadaver study? How should the clinician change their orthosis prescription based on what is seen with your MTJ examination technique? How does the MTJ examination technique predict pathology or foot kinematics or foot kinetics during gait?

    I am truly interested in your opinion since I simply didn't find the technique to be that useful for me, or my patient.
     
  16. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    Even if the midtarsal joint is a multiaxial joint, there are major differences between the range and direction of motion of one individual to another. Are you suggesting that since the MTJ is multiaxial, we should treat all MTJ the same? Since you find axial differences at the STJ so clinically significant, it surprises me that you don't have the same appreciation for axial differences at the MTJ.

    Some individuals have a highly mobile MTJ (almost ball-in-socket like) while others have a very constrained axis of motion. Functionally these two feet are very different. Some have a much narrower envelope of motion while others have a much broader envelope of motion. Those who have a much broader envelope of motion or are hypermobile, tend to pronate more than those who don't, and they tend to have more forefoot abduction during weightbearing activity than those with a smaller envelope of motion. In my case, I have a very rigid MTJ as compared to others. I think this, in conjunction with a plantarflexed 1st ray explains why I got such severe 1st MTPJ callouses and hematomas in my racquetball and tennis playing days. So yes, it helps explain pathology.

    If you examine a patient with adult acquired flatfoot using this technique, you will find that the MTJ has adapted an increased range and direction of motion as compared to the opposite foot (if unilateral) or as compared to the average subject. When I conduct this examination on subjects, I'm looking for relative differences between one individual and another, or between one foot and the other. The greater the envelope of motion, the more controlling I need to make the orthoses. And if there is a much more vertical axis (much more forefoot ad/abduction available), then I know this foot will require an orthosis designed to resist transverse motion (inverted cast, medial heel skive, lateral clip, deeper heel cup, no motion rearfoot post, lateral flange, etc.) One (I) can detect subtle differences between individuals and in some cases, this may be an early sign of pathology such as adult acquired flatfoot. For example in my wife's case, I noticed increasing motion at here MTJ over time. She is a runner who used to walk around the house barefoot. I advised her to wear her shoes and orthoses in the house because of increasing MTJ mobility and her decreasing arch height that has occurred over time.

    Let me ask you a question. If this technique was so well taught, why has no one done any research on it? I recently had two Australian podiatrists visit me at the lab. I asked them to show me how to examine the MTJ. Neither one of them used this technique. So I would contend that this technique is not being taught and is poorly or not understood. I have made this same observation time after time. We use open chain examination of the STJ, 1st MTPJ, ankle, knee and hip. So why not the MTJ?

    The hip and shoulder are very good examples of a multiaxial joints in from which clinicians derive important clinical information by examining range and direction of motion. So your logic, that because the MTJ is multiaxial this technique isn't useful, should also apply to the hip and shoulder, right? But since we do get valuable information from examining other multiaxial joint such as the hip and shoulder, then I contend we can get clinically significant information by examining the MTJ in the same way.

    Jeff
     
  17. Phil Wells

    Phil Wells Active Member

    Hi Jeff and Kevin

    I do use this technique to help me direct my assessment approach. For example if I am dealing with DMICS, this very subjective assessment starts to direct me towards the underlying pathological forces.
    Although I have no research to back it up, I do find it very useful, and when combined with a few other tests, Supination resistance, Stjt axis, ankle RoM and Qom etc..., it does work.
    Also it has become a good indicator of potential arch irritation - especially in runners - and can directly effect orthotic Rx.

    Cheers

    Phil
     
  18. Jeff Root

    Jeff Root Well-Known Member

    Thanks Phil. My only objective is to encourage others to take a look at the MTJ using this technique. It takes training and practice to acquire and refine this skill. The clinicians observational skills and sense of feel are very important clinical tools and it is part of the art of medicine that can have a basis in science. I'm glad to see that you have found this technique beneficial because I think it provides very meaningful information.

    Jeff
     
  19. Jeff:

    I would agree that this technique is not taught. I haven't taught it for over 25 years and I think I was the only one teaching it at CCPM in the mid-1980s. Since you think that this technique is so important, then you should do a instructional video on it and post it up on YouTube so others can learn why you think this technique is so important.

    As far as assessing the midtarsal joint and its function, there are other ways of assessing midtarsal joint function and assessing its stiffness, other than pushing on the forefoot in a way that attempts to get the forefoot to move on the rearfoot along an imaginary joint axis.

    That's all I have time for now.

    To paraphrase Nester, "The joint axis does not determine joint motion, rather, it is the joint motion that determines the joint axis." This is especially important when considering midtarsal joint kinematics and kinetics.
     
  20. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    I agree. That is why we use motion to evaluate the axis, not the axis to evaluate motion. When we examine the internal and external ROM of the hip, we are not looking at each and every axis of motion at the hip joint. We are intentionally looking at rotation about a vertically oriented axis because we want to evaluate transverse plane motion in the same way that I adduct and abduct the forefoot at the MTJ to evaluate the range of transverse plane motion at the MTJ. But unlike the hip, I also invert and evert and plantarflex and dorsiflex the forefoot on the rearfoot at the MTJ to determine the quantity (range) of motion in all three cardinal body planes.

    Jeff
     
  21. rdp1210

    rdp1210 Active Member


    Unfortunately, I have missed a lot of the bantering here due to being out of town and totally off the network for almost a week.

    Kevin, I think you're being a little bit contrary here, I don't know why, maybe it's just to stir the pot and get people boiling. Interesting that you make the statement, "Manipulating the foot with your hands to produce the motion you want to see does not necessarily mean anything ..." Maybe we could say that about any joint, that people are just manipulating the joint to see the motion they want to see. Let's forget about the midtarsal joint, and instead let's first look at the hip joint. The hip joint represents a true ball-in-socket joint. How many axes does it have, Kevin? Please defend mathematically your answer.

    Next, does it make any sense to measure the range of motion of the hip joint in any direction? What useful information could be gained about the kinetics and kinematics of the hip joint by taking a set of measurements of the abduction/adduction, or the internal/external rotation, or the flexion/extension range of motion of any joint?

    How about the range of motion of the knee joint? Does it make any sense to take any goniometric measurements of the flexion/extension motion of the knee joint? How about the frontal plane motion in the knee joint?

    Finally, please discuss for me the usefulness of taking any goniometric measurements of the ankle joint. I find less reliability in trying to examine the ankle joint than any joint, including all foot joints.

    You seem to be saying that because you haven't seen any "scientific papers" about available ROM of the MTJ (not it's actual kinematics), that it must not be important to know. I find such thinking to be extremely narrow minded, and definitely not scientific at all. If you can justify measuring the ROM of any joint in the body, then you must allow that measuring the ROM of the MTJ is also important. Just because we don't have good instrumentation yet to take reliable clinical measurements does not mean it shouldn't be done. I am not saying that the Weed or the Root methodology of evaluation is the best, it's just that we haven't been able to do better yet. On the other hand I will only toss away the idea that I would want to even examine for available ROM of the MTJ only if you can justify that I don't need to measure the ROM of any joint in the body.

    Take care,
    Daryl

    BTW - I will stand by my statement I made in Vancouver

    1. There is no such thing as Root biomechanics
    2. There is no such thing as frontal plane biomechanics
    3. There is no such thing as sagittal plane biomechanics
    4. There is no such thing as tissue stress biomechanics
    5. There is no such thing as subtalar joint axis biomechanics
    There is ONLY biomechanics.

    I think it's time we all grew up and quit bickering so much. If half the time was spent by the profuse writers on this site in actually pursuing research as was spent in endless arguments, the world would have a lot greater knowledge, and the JAPMA and other peer reviewed journals would be overloaded with papers by these writers, actually giving us new knowledge.
     
  22. The problem is that when you move the foot you create axes, so one must be very careful that the movements we induce during examination are uniplanar. This is really just a clinical interpretation of the model of three references axes about the MTJ (Nester C.J., Findlow A: Clinical and experimental models of the Midtarsal Joint. J Am Podiatr Med Assoc 96(1):24-31, 2006). We can then look at dorsiflexion-plantarflexion, abduction-adduction, inversion-eversion as seperate assessments- this is what I do clinically. When I prescribe and manufacture orthoses, I try to consider how the design characteristics of the orthoses will alter the moments about each of these three reference axes at the MTJ.
     
  23. To this I would add, that without knowledge of the force being applied in goniometric measurement, goniometric measurement is pretty meaningless.
    I agree, no one book nor paper on foot and lower extremity biomechanics should be held up as being "the true word of the Lord". We need scientific critique, to draw in all of our scientific knowledge not just of mechanics and biomechanics, but all aspects of scientific understanding. We do not need dogmatic adherence; scientific critique is to be encouraged, not stamped out by those who hold a vested interest. We need to be cogniscient of the principles of mechanics as they are applied to the human body and flag up when anyone advocates something which flies in the face of such mechanical principles. For example, if we have someone advocating a treatment which will increase inversion moment about the ankle and subtalar joints as treatment for chronic lateral ankle instability, there has got to be something wrong here and such behaviour should be flagged as being erroneous with mechanical principles and our understadning of tissue injury physiology- do you agree Daryl?

    With all of this scientific endeavour in all fields in mind, I'd like to ask you a question Daryl that will only require a yes or no answer: given all the information which science has provided us, do you think Root's biophysical criteria for normalcy is a valid concept?
     
  24. Jeff Root

    Jeff Root Well-Known Member

    Simon,

    I agree! And this MTJ examination technique is just one element of a much more comprehensive biomechanical examination. We need to look at the entire puzzle and the MTJ is just one, but an important, piece of the puzzle. In some cases, it is just a pertinent negative. In other words, I have examined the MTJ and ruled out that it is a contributing factor to the patient's symptoms. In other cases, I may find that it is related to the pathology in question.

    Jeff
     
  25. Just spotted this and it is an important point I raise here. When we examine the motion of the forefoot relative to the rearfoot, we are not examining motion at the MTJ. The MTJ being usually defined as the calcaneo-cuboid (CCJ) and talo-navicular joints (TNJ). Our clinical examination in no way isolates these two joints from the other joints of the midfoot. This is very important to recognise. When we move the forefoot on the rearfoot we are moving all of the joints between our hands, not just the CCJ and TNJ. Very important to recognise this, N.B.
     
  26. efuller

    efuller MVP

    To add to what Kevin has said. When we are talking about different positions of the STJ axis we are comparing different feet. Yes, there are different axial positions across different feet for the STJ. For a single foot the axial position stays relatively constant because of the constraints to joint motion. However, for most feet, the midtarsal joint doesn't have motion constrained around one or two axes. So, it would be appropriate to pay less attention to the position of axes in joints where the motion is less constrained.

    I agree with the envelope of motion comments. Determining a large envelope of motion versus a small envelope of motion is a different concept than examining where the axes of motion are or using textbook axes of motion to explain pathology.

    I can really get behind this. This is a great example of how an observation affects clinical decision making. If you have noticed that certain orthotic modifications make the orthotic work better only when you see certain observations in the foot then you have good criteria to modify a prescription. This applies to the discussion we were having on the other thread about the need for defining normal. We don't really need to decide that a particular value for envelope of motion is normal or abnormal. We just need to know when we need to alter are treatment to make it more effective.

    So, we need a research question based on the relative amount of motion in the envelope of motion of the midtarsal joint. I think you mentioned that when you saw a high amount of motion that you would see a more pronated foot. (correct me if I'm wrong). So, now we need measures. We would have to quantify the volume of space that bones distal to the midtarsal joint could occupy relative non moving proximal bones. Then we would have to find a measure for more pronated. ????;) Or we could try and correlate the volume of envelope of motion with pathology. We could just try all the pathology or we could try and find a theoretical link.

    Feet with more abduction of the forefoot on the rearfoot would tend to have a more medial position of their STJ axis. This is one way we could define "more pronated." Feet with medially deviated axes would be "more pronated" than feet with average STJ axes because they would tend to have a higher pronation moment from the ground. At that point we would be using high envelope of motion as a proxy for STJ axis position. We might as well just use STJ axis position.

    Any other theoretical connections between a high envelope of motion of the midtarsal joint and pathology?

    Eric
     
  27. Jeff Root

    Jeff Root Well-Known Member

    Please notice the difference between Kevin's technique and mine (i.e. Merton Root's original technique). Kevin grasps the foot at the 4th and 5th MPJ's and moves the entire forefoot in space. I grasp the foot on the cuboid and navicular to isolate MTJ motion. As a result, I am not applying force to create motion at the joints anterior to the MTJ. I am holding the calcaneus in one hand and I'm moving the cuboid and navicular with the other hand and I'm feeling and visualizing the relative motion at the MTJ. Yes, the other motions are also clinically significant but in this exam, I'm only attempting to evaluate the MTJ.

    Here is Kevin's technique:


    And here is my technique. Notice how I apply force in different directions to differentiate transverse, sagittal and frontal plane motion at the MTJ. This motion will be different depending on the subject in question. This individual has a highly mobile MTJ and much more transverse plane motion (ad/abduction) than most patients. Kevin's subject was also hypermobile. But if we compare this to other patients we will find significant differences in their motion and this can be seen functionally. I find that the relative difference in these planes of motion is helpful because it tells me what forces I might need to resist with my orthosis.

    Jeff



     
    Last edited by a moderator: Sep 22, 2016
  28. Jeff:

    The technique that I demonstrate in this YouTube video is not the technique that John Weed taught me. Rather I chose this technique specifically for this video to better demonstrate the envelope of motion of the midtarsal joint in this foot. Your technique is what John Weed taught me and is one I saw Dr. Root demonstrate many times in his seminar. I no longer use the Root/Weed MTJ examination technique since I found it to be not useful for my practice.
     
    Last edited by a moderator: Sep 22, 2016
  29. rdp1210

    rdp1210 Active Member

    Simon, I partially agree with you. We need to know as much as possible. We need a knowledge of the forces, we need to know the availability of motion that any joint has to work within, the "axes" around which the joint has to work. I have mentioned before that we really need to better talk about degrees of freedom of motion and the availability within each degree. We have made a little inroad to understanding the STJ in the last 30 years, but haven't begun to tackle the biggest hurdle, the MTJ. I believe I argued that Nester's work neither confirmed nor contradicted the Hicks model, as there is a mathematical explanation how both could could exist, especially if the axes are fixed with the calcaneus or cuboid (like the fixation of the STJ axis to the talus). If you talk to Erin Ward, he will confirm that over 20 years ago he and I started looking at the center of mass and the radius of gyration of each segment of the foot. Erin had some very excellent ideas of how to determine the radius of gyration around each axis. This is a work that needs to be completed.


    The question is not a valid question, because there are so many components of Root's criteria. ("No, Mr. Barrister, I'm not still beating my wife.") As I am sitting at home today, and do not have my Root textbook in front of me, and cannot quote the components verbatim, so I am not going to enumerate and discuss each one at this point in time, however I will say that I can make a mechanical argument for at least some of the biophysical criteria for normalcy, i.e. criteria for idealization. If you want to get into the definition of normal again, fine. We both agree that Root's criteria were ideal, not average. How far one can deviate from ideal has great variability, just like every other measure of human body function, which is why we talk about the "art of medicine," which may never be replaced by the "science of medicine". (BTW - maybe you could tell me what the normal blood sugar should be) So the little boxing matches we see carried out in this forum are a microcosm of the boxing matches seen in so many other fields of medicine. :boxing:

    You bring up the concept of vested interest. It is important that we identify all vested interests by all parties. What vested interests do you have? What product are you selling? What papers have you published that you don't want seen put down? As I have pointed out, tissue stress is not a theory, it is a group of principles that have to be included in all discussions of foot function. It is not the end-all, it is one little part of the whole. STJ axis principles are not an end-theory, but only one little part of the whole. Functional hallux limitus are principles that help solve certain problems, but it is not an end theory. Forefoot to rearfoot relationships are principles only and are part of the whole. And I think it is time that we quit saying that the 2 axis theory of the MTJ is a Root concept, it is a Hicks concept and Root had no other information to go on. So let's call it what it is, the Hicks MTJ model.

    I'm not really sure what you are referring to as someone advocating a theory which increases the supination moment around the STJ axis as a treatment for lateral ankle stability. However in regards to flags going up, a flag also needs to go up whenever someone's theory of foot function doesn't include all the joints of the forefoot.

    One question I would like you to comment on, Simon, which multisegment model of the foot do you prefer and why?

    So next Monday, I'll be back to continuing work on my current research project as well as treating all those diabetic ulcers, which will include all the principles you see discussed here, as well as many others people rarely discuss. Maybe you could tell me what the ideal peak pressure should be under the first metatarsal head in a diabetic neuropathic patient. Should I be doing dorsiflexing osteotomies on all first metatarsals that have chronic ulceration under the first metatarsal head? Why or why not?

    Have a good weekend
    Daryl
     
  30. efuller

    efuller MVP

    Nigg had a paper on modeling. He found that your research question determined how detailed your model has to be. He looked at predicting Achilles tendon tension and found that a simple model could be very close to more complicated models in predicting Achilles tension. So, if a simple model is predictive, then we don't need to use more complicated ones. So, we need the studies to find out if STJ axis position can be predictive of pathology. One measure might be enough for some pathologies.

    Eric
     
  31. Since Daryl evaded answering your question, Simon, let me answer it for you.

    Root et al's Eight Biophysical Criteria for Normalcy was not based on a single piece of scientific research evidence that supported any of the eight criteria listed. Not only are heel bisections and subtalar joint neutral determinations subjected to so much inter-examiner errors to make these determinations nearly useless for comparing feet and lower extremities between one examiner and another, but each of the eight criteria have not, in my 30 years of examining tens of thousands of individuals, been able determine which individuals will function normally or not.

    Therefore, is Root et al's Eight Biophysical Criteria for Normalcy a valid concept? No.

    In fact, I think that the proposing a single set of ideal structural/functional parameters that was not based on research evidence, but rather based on pure conjecture, has actually done more harm than good for the field of podiatric biomechanics over the past 44 years since these Eight Biophysical Criteria for Normalcy were first published. We, as a profession, will now need to spend the next four decades unteaching these erroneous concepts to enable podiatrists around the world to have a more realistic view of foot and lower extremity biomechanics and the natural variation that exists within the human foot and lower extremity.
     
  32. rdp1210

    rdp1210 Active Member


    I reviewed your video, Kevin. I agree that there are 2 axes of motion that you demonstrate, i.e. a vertical axis and a transverse axis, and lots of combinations of motions around those two axes. The one axis you don't demonstrate is a longitudinal axis that allows inversion/eversion motion. Now there are several questions I would like to know about this patient:
    1) what is the quantitative ROM around each of the 3 axes of motion.
    2) does the quantitation ROM around each of the 3 axes of motion change with various STJ positions, and by how much.
    3) why are you not interested in knowing the quantitation.

    As I have related, 30 years ago I described to Mert that I believed there were 3 axes of motion of the MTJ, and I would not bring this up if Mert hadn't publically stated to everyone at his conference that I believed such. I don't remember if you were at that conference. Maybe you could call Bill Orien and ask him about the MTJ concept at the time they wrote the Normal and Abnormal Book.

    What I find interesting is that some people truly have 3 orthogonal axes of motion but some do not. Some have 3 axes of motion but they are not orthogonal. In these individuals you see available motion around a vertical axis, and also a longitudinal axis, but there is no transverse axis that produces pure sagittal plane motion. Instead the 3rd axis is a Hicks-like oblique axis, where the only way you can get plantarflexion is with a linked adduction motion. Guess I'll have to get my video camera out and take my own video of this phenomenon. Can't say I understand it, but I'm definitely interested in knowing more, and I am looking for quantitative instrumentation. As I mentioned before, it's time for all us to talk less and do more to understand the motions of the midfoot.

    Take care,
    Daryl
     
  33. rdp1210

    rdp1210 Active Member


    Thank you Kevin for posting each of these criteria. I did not have them at my fingertips when I replied, so please forgive me for appearing to obfuscate. You certainly seem to avoid answering questions that I put forth.

    As I noted, we have to look at each of these as singularities, not as a single whole. The next question is not whether they do exist, but whether they should exist for ideal function. Now what kind of experiment would you expect anyone to do to prove an ideal? You can produce experiments to show average, but you need to do engineering analysis to show ideal. I will ask you, what scientific proof have you produced to show where the ideal STJ axis should lie? You have written lots of theory papers, but you really haven't produced much scientific data on what the ideal is.

    If you want to discuss each of the Root criteria one at a time, let's start with #1. Should the lower 1/3 of the leg be vertical to the ground in static stance? Why or why not.

    Daryl
     
  34. I'll let others answer for now. We're off the morning for a four-day motorhome trip to Yosemite Valley-my favorite place in California.
     
  35. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    Don't you think you are doing the exact same thing with STJ axis location? The definition of deviated is:
    So by saying that the STJ axis is medially or laterally deviated, you have established a norm from which it must vary. It seems hypocritical to accuse Root, Weed and Orien of proposing norms that are not based on "research evidence", and then propose your own norm for the location of the STJ that is not based on research evidence. Like Root et. al., you offered a theory that needs to be tested at some point in the future after you disseminated it. That is a common practice with theories, since they are not facts and should not be accepted as fact.

    Jeff
     
  36. rdp1210

    rdp1210 Active Member


    Have a great trip -- we always loved visiting Yosemite when we lived in California. It's a great place to contemplate.

    Daryl
     
  37. rdp1210

    rdp1210 Active Member


    Actually Jeff, I did accept the Kirby STJ axis norm only after doing my own research on STJ axis location and publishing my results along with theoretical values of the pronation-supination torques based only on values that Russell Jones proposed as the normal FF and RF forces. Again it was theoretical and it required a tension in the Achilles tendon that was reasonable.

    Again, clinical measures of average do not establish any type of ideal, but it may give us a range around which we can expect few problems. Since mathematics is the only pure science, to establish an ideal, we have to perform what in physics is called "the thought experiment." I don't believe that is ever possible to use a study of clinical subjects to establish an ideal. Longitudinal studies are the best hope of coming close, and there are few of these in the study of lower extremity mechanics. As a comparison, I think we need to look at the millions of dollars that have been spent on trying to established norms for blood pressure and blood sugar, yet these "norms" are constantly shifting. That's why we use science as a background and then still have to practice the "art of medicine." I can live with so called dichotomy, that an ideal is set, but we find no one that really matches that ideal, but we get a better clinical result when we move toward that ideal. Just because McPoil or anyone else finds people that match an ideal doesn't mean that we can't still have that ideal.

    Like I said, I will be looking forward to Kevin discussing Root criteria #1. Again, this should be a great theoretical discussion, based on sound mechanics. I also welcome other people contributing to this mechanical theory discussion. Simon should jump on this with his understanding of finite element modeling. This is not a discussion of what people are measuring, only what is ideal.

    Have a good weekend,
    Daryl
     
  38. efuller

    efuller MVP

    Daryl, I'm not sure what you mean by look at these as singularities. Both you and Jeff have been talking about how we have to combine many things together to understand foot function. (Actually I may be confusing posters, correct me If I'm wrong.) Is your use of the term singularity meaning that we should not combine the effect of different measurements Treating each of the biophysical criteria of normalcy as q separate, disjointed entitie might be creating a huge internal inconsistency in Root et al theory.


    One could model various anatomical structures to determine if certain measurements, like lower 1/3rd of the leg would have an effect on the internal forces on those anatomical structures.

    Looking at Kevin's frontal plane model of the STJ we can make some predictions. When the axis is more medial we are more likely to get problems related to high pronation moments. When the axis is more lateral we are more likely to get problems from high supination moments. So, the ideal should be somewhere in the middle.

    As you read the excerpts from Normal and Abnormal that Jeff posted, you see a high similarity to my last sentence in the above paragraph. One difference was that Kevin's model is looking at whole foot influence (center of pressure) as opposed to separating forefoot influence and rearfoot influence.

    Actually, the ideal may not be exactly in the middle of no moment from ground reaction force. There is much more likely to be catastrophic failure (sprained ankle) with an axis that is too far lateral as opposed to long term "overuse" in structures that resist pronation moment from the ground, when the axis is too far medial. If our ability to produce offspring was related to how well our feet worked, I would predict that evolution would tend toward the best trade off between too much pronation and too much supination. So, perhaps the average STJ axis in the population should be considered the norm.



    We should decide on what areas we should evaluate each of the criteria of normalcy. I would like to suggest the following question. Feel free to add other questions.

    Is it likely that a value found with this measurement will be predictive of a particular pathology?

    For knee pathology, the lower 1/3 of the leg would be a weak predictor of frontal plane moments acting on the tibia. A better measure would be center of pressure in the knee joint and center of pressure under the foot.

    For STJ pathology: The more inverted the lower 1/3 of the leg, the more likely there will not be enough eversion range of motion to bear significant amount of weight on the medial forefoot. This will tend to create high pronation moments at the STJ and increased likelihood of sinus tarsi pain.

    However, if there a large amount of forefoot valgus, there could be significant medial forefoot weight bearing in the presence of a high degree of tibial varum. So, a better predictor of whether there is too little eversion range of motion is the maximum eversion height test.

    Anybody want to add anything else to the lower 1/3 of the leg criteria for normalcy.

    Eric
     
  39. In my humble opinion

    the discussion of normal makes me cringe

    Normal call only be N = 1

    Another point A major problem with Root discussion are there is

    1. Roots 2 texts
    2 The bastardised version taught at schools
    3 individual interpretation of Root
    4 What people such as Jeff Daryl Kevin say Root et al say Root et al said after the text was produced

    With Tissue stress we are bound by the laws of Physics , axis, motion, moments etc

    The understanding and practical application are always up for discussion and development as are Roots but the ground point of tissue stress is again IMHO much more solid and easier to cross transfer between professions.
     
Loading...
Thread Status:
Not open for further replies.

Share This Page