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Biomechanical challenges - a new model (or just an old one revisited??)

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Paul B, Jan 23, 2007.

  1. Paul B

    Paul B Active Member


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    Have been interested in some of Craig’s and other members recent (and some more long standing) postings re biomechanical models of foot problems. Attending Craig's workshop in Brisbane late last year, I was really impressed by both his enthusiasm and body of knowledge. Really informative and well done!!

    Of more recent time (mid 2006) QUT podiatry clinic has acquired a high definition ultrasound machine, which is providing us with remarkably incite into foot pathology. This system, when used real-time, is providing so much more diagnostic value that ALL the foot biomechanics theories combined. The long known difficulty in establishing a cause-effect relationship (using most biomechanical models) may have, in my opinion, proved to have been more of a "distraction" to the profession than it has been "worthwhile".

    Just examining the forefoot alone (in 70 cases) we have identified 15 clear and unequivocal diagnosis of "disparate" foot pathology (hardly explained by singular biomechanical models - i.e. the oversimplified approach). The evidence is "black - (oedema) and white - (connective tissue).

    The use of (real-time) high definition (i.e. 14 MHz) ultrasound in podiatry settings has once again reminded me of the basics......you simply must know, and accurately identify, the anatomical structure which has been "stressed" in order to provide effective treatment.

    I believe this (now much more affordable diagnostic US) may be one of the most important adjuncts to clinical podiatry practice of biomechanics, than any other current "system", "theory" or "approach".

    I'd be interested to hear other podiatrists views on this topic?

    PB
     
  2. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    Paul

    Couldnt agree more.

    Unfortunately, the history of teaching "biomechanics" at undergraduate level has led to a couple of generations of podiatrists that "diagnose" biomechanical irregularities, rather than the true pathology on hand.

    The amount of times I have heard a student (or a registered podiatrist) establish a diagnosis as "forefoot varus" (or something similar), leaves me frustrated that they are continually confusing biomechanical theories and descriptions, with a clear-cut anatomical pathology diagnosis.

    Reasserting an emphasis toward teaching students to "make the diagnosis" through clinical examination and adjunctive investigations such as ultrasound - in 2nd/3rd year, then adding the biomechanical "theory" later (4th year?) to assist in explaining a mechanical pathology would seem obvious to me.

    As an eccentric DPM whom you know well would often say in class, "make the diagnosis, and treatment will take care of itself".

    LL
     
  3. Craig Payne

    Craig Payne Moderator

    Articles:
    6
    Paul will remember one of my monologues from the seminar I did when talking about the frustrations of being an educator:

    Me: What is your diagnosis?
    Student: They have 3 degrees of this and x degrees of ....
    Me: NO. What is actually wrong with this patient?
    Student: They have an abductory twist and a forefoot...
    Me: Fail
     
  4. Paul:

    I don't really understand your point. "This system, when used real-time, is providing so much more diagnostic value that ALL the foot biomechanics theories combined." Is it that since you can now "see" the structures with ultrasound that you now know how the foot works mechanically?? What do you think biomechanical models of the foot are for?? Are they there to better teach you anatomy of the foot? Or do they serve the purpose for allowing you to make an accurate diagnosis? Do biomechanical models of the foot teach you how to palpate, perform range of motions, perform valuable clinical tests, do visual gait evaluations or trim a painful callous?

    No! Biomechanical models of the foot are there to help you understand foot function, how the foot works, and how external and internal pathological forces interact on and within the foot to create tissue injury. Then, with our ability to make an accurate diagnosis with our hands, ears, eyes, X-rays , and yes, even a new little ultrasound unit, biomechanical models serve the important purpose of allowing us to understand how injury occurs either on the foot or inside the foot so that we may better design treatments for our patients.

    While diagnostic ultrasound is indeed something that may help in diagnosing which structure may be injured and how severe it may be injured, it still doesn't tell you a thing about why the injury occurred or how the foot is working abnormally during weightbearing acivities to cause the injury in the first place. This is the purpose of biomechanical models: to understand the biomechanics of the foot and lower extremity during weightbearing activities, not to make accurate diagnoses.

    Please don't confuse biomechanical models with the skills that every great clinician has: an excellent knowledge of foot and lower extremity anatomy, good history taking ability, ability to note and categorize anatomical and functional details and an excellent knowledge of clinical tests and procedures. Biomechanical models do not replace excellent clinical skills....they rather work hand in hand to allow the clinician to arrive at the best treatment method for their patients.
     
  5. Paul B

    Paul B Active Member

    Hi Kevin, Thanks for your response

    Paul:

    I don't really understand your point. "This system, when used real-time, is providing so much more diagnostic value that ALL the foot biomechanics theories combined." Is it that since you can now "see" the structures with ultrasound that you now know how the foot works mechanically?? What do you think biomechanical models of the foot are for?? Are they there to better teach you anatomy of the foot? Or do they serve the purpose for allowing you to make an accurate diagnosis? Do biomechanical models of the foot teach you how to palpate, perform range of motions, perform valuable clinical tests, do visual gait evaluations or trim a painful callous?

    No! Biomechanical models of the foot are there to help you understand foot function, how the foot works, and how external and internal pathological forces interact on and within the foot to create tissue injury.

    Yes, I agree with some of the points above, except for the last 4 words "to create tissue injury". This gets back to the assumption of a cause - effect explanation, which very few models do, particularly if you were to assess them by traditional scientific approaches (ie tests of specificity/sensitivity/reliability/repeatability etc), then most models don't advance our understanding, as much as specific identification of damaged anatomy does.

    Then, with our ability to make an accurate diagnosis with our hands, ears, eyes, X-rays , and yes, even a new little ultrasound unit, biomechanical models serve the important purpose of allowing us to understand how injury occurs either on the foot or inside the foot so that we may better design treatments for our patients.

    I'd have to disagree with this. Most models are like "water down the drain", ie it all follows the same path (perhaps only in a different direction depending on your hemisphere). Ultrasound investigations, when used appropriately, are producing far more useful information for day to day podiatry practice, and particularly moreso than X-Rays.

    While diagnostic ultrasound is indeed something that may help in diagnosing which structure may be injured and how severe it may be injured, it still doesn't tell you a thing about why the injury occurred or how the foot is working abnormally during weightbearing acivities to cause the injury in the first place. This is the purpose of biomechanical models: to understand the biomechanics of the foot and lower extremity during weightbearing activities, not to make accurate diagnoses.

    Again I'd have to disagree. The "models", and here I'm talking about the 5 most common (although many more exist) are far less helpful in "explaining" direct linkage to pathology. Having said that, I tend to subscribe more to the work of McPoil etal, which basically calls it as it is. Ruptured plate - fix it, synovitis - fix it etc etc - all soft tissure, which is my perfered "model".


    Please don't confuse biomechanical models with the skills that every great clinician has: an excellent knowledge of foot and lower extremity anatomy, good history taking ability, ability to note and categorize anatomical and functional details and an excellent knowledge of clinical tests and procedures. Biomechanical models do not replace excellent clinical skills....they rather work hand in hand to allow the clinician to arrive at the best treatment method for their patients.

    To a point this might be true, but unfortunately most of the models just simply don't stand up to the true tests of scientific enquiry, so most need to be looked upon with extreme caution, and what we agree upon and you acknowledge above, quality clinical skills (particularly diagnostic) are really the essence of the matter.

    Regards

    Paul.
     
  6. CraigT

    CraigT Well-Known Member

    I think all posters have made very valid points-
    I feel the most important thing is that the practitioner has a clear aim in their treatment protocol, and this is made clear and communicated to the patient.
    While a clear diagnosis is important, it may not be the most important aspect of our assessment.
    For example-
    A patient presents with multiple pathologies of the lower limb- lets say (broadly) anterior knee pain, shin soreness and plantar heel pain- and, as an experienced clinician, you can see that they have all the signs of a 'classic over pronator'. Do you spend time specifically identifying each pathology? Or do you go ahead and try and address biomechanical issues...
    Now looking at this example in relation to what CP posted, the diagnosis could be made of multiple biomechanically related pathologies. Treatment would be to address these, probably on very many levels (training, footwear, postural control, orthoses). The diagnosis would not be 'pronation', or a phantom 'FF Varus'.
    I have had many a patient present for a second opinion, and recount how they have orthoses because they have 'flat feet' or they 'pronate'-
    With respect to Paul B's observations- With the wide number of pathologies noted in the forefoot, the questions arises- How did these occur?? Assuming no systemic problems, is it not reasonable to say that virtually all foot pathology is biomechanical in origin at some level. Lets face it- essentially all the external forces applied to the body as we move have to travel through the foot. It is how they travel though the foot and the influences they have which varies so much between people.
    Perhaps the wide range of pathologies observed by Paul B means that we need to more closely examine FF biomechanics, to be able to determine the cause for this effect.
     
  7. CraigT

    CraigT Well-Known Member

    Testament to my typing skills is that once I posted above, Paul has already replied to Kevin...

    I think I am understanding your point more clearly now...
    In identifying damaged anatomy I can see that we have more knowledge, but does it help us in undestanding how it occurred?
    Surely it is critical to find the causes of such pathology
    It is perhaps the biggest challenge for our profession is to stand up to rigorous scientific scrutiny- any experienced clinician would agree that there is a large component of art in what we do. I often explain to patients that while is in theory scientific, it is art in practise.
    Do you think it will ever be possible to find cause and effect relationships which stand up to traditional science when we are dealing with such a wide array of individual variability and environmental influences??
     
  8. I think Paul and Kevin both make some good points and that the truth, as usual, lies somewhere in the middle.

    I share Craig P's frustration with the

    approach. To often I see clinicians over rely on their knowledge of Biomechanical "models" to save them the trouble of carrying out an actual diagnosis. The extreme form of this is of course certain unscrupulous companies who presume "Overpronation" (how i hate that word; over what? When during gait? why, how fast? Its not even a useful observation by it's self much less a diagnosis!) to be the root of all evil and train their salespeople to sell the "cure" without bothering to consider the problem or even learn any diagnosic skills at all!

    However

    The other extreme is equally useless. A diagnosis of a strained this or ruptured that is not actually useful unless we understand why it is strained or ruptured and how to manipulate the structure / function of the foot to allow it to heal and then prevent it re injuring. To do this we need to understand in as much detail as possible how the foot works and for that we need "biomechanical theorums"

    I would compare the two sides of this debate to a radiographer and a plaster technician. No point casting if the leg's not broken, no point knowing the leg is broken if you cannot plaster it!

    So far as the argument that
    goes, the fact that we may not yet understand the FULL picture (which in a biological system may not be even possible) should not discourage us from using what we do know. I'm no expert at texas hold 'em. I get obliterated by better players from time to time. However what i DO know lets me fleece noobs on party poker fairly regularly!

    Respectfully

    Robert
     
  9. Paul B

    Paul B Active Member

    Some fantastic observations made here by Craig T and Robert. I pose to you both the following question. If you had 15 minutes to decide “what the problem was” would you (a) spend time looking to explain to them (the patient) what the pathology was in terms of a “biomechanical explanation” or (b) satisfy yourself that you truly knew “what was broken?”. PB
     
  10. Illogical question. I could'nt explain "what the pathology was" in either sense until i knew "exactly what was broken." :confused: As a fan of the tissue stress model i would not consider any deviation (within reason) from "the norm" to be a pathology unless it is linked to damage in a tissue (the broken bit). Therefore i would need to be, in your words, satisfied that i knew what was broken to adequatly assess the biomechanics.

    For example many serious runners are massivly pronated during running. If they are are not in pain and are functioning well i would not consider that there was a biomechanical problem. Presented with the same foot with tibialis posterior insertional pain i would consider it to be a problem.

    Don't really understand where you are going with that question but keep going!

    Interesting thread BTW

    Robert
     
  11. CraigT

    CraigT Well-Known Member

    In this sort of situation I would be looking at what may be the cause of the pathology based on history and a brief examination of the mechanics of the invididual-
    If a mechanical cause was suspected (gradual onset, no obvious acute trauma, obvious clinical evidence of mechanical deficiency) I would also probably try some tape to unload the area with the possibility of additional padding.
    This will often change the symptoms immediately, and would confirm suspicion of mechanical involvement. If there is no change, or if the patterns are more unusual, then you would definately investigate the diagnosis further-
    I am not sure I agree here- I have also seen asymptomatic runners who have reported that they feel like they can run more easily and efficiently once they have had mechanical deficiencies addressed. Once again taping can be a useful indicator.
     
  12. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    Thought the following might be relevant to this discussion.

    Bagliavi's Cornerstone: "The foundations of medicine are reason and observation"

    Kline's Critical Keystone: "Reason and observation get much sharper when prodded by an unexpectedly abnormal lab test from the battery of random tests ordered."


    :D

    LL
     
  13. Paul B

    Paul B Active Member

    Thanks for your responses here,

    I think we are in agreement, with understanding the need to assess the "relative risk factors". We know from experience and could easily list (in order of relative risk) contributory factors to the scenarious you both provide above i.e,

    Increased level of physical activity, age related degeneration, weight gain, poor conditioning etc etc etc. Variations for a "biomechanical norm", as a relative risk, just don't feature consistently enough. Plently of research evidence to support this (ie in most instances the patients biomechanics haven't changed from before they become symptomatic, to when they become symptomatic ..(excluding things like tendon rupture/dysfunction etc etc.). Orthoses / strapping (as pointed out above) all do the same thing, control forces applied to the lower extremity, irrespective of the biomechanical "causal explanation" (that was my water down the drain metaphore above).

    So my argument is, based on applying the soft tissue model of pathology. It would appear we are better off spending the 15 minutes (challenge posed above) really understanding and diagnosing the anatomical pathology and getting that right....."Just examining the forefoot alone (in 70 cases) we have identified 15 clear and unequivocal diagnosis of "disparate" foot pathology the evidence is "black - (oedema) and white - (connective tissue)".

    Am interested in other readers thoughts on this question. Where should our (limited) energy & time be focused? Theorising about causation / accepting the fact biomechanical stress is only a single part of the problem or really satisfying ourselves we know exactly what the pathology is ????

    Your comments?

    PB
     
    Last edited: Jan 24, 2007
  14. CraigT

    CraigT Well-Known Member

    Some good discussion here!
    Is I am sure we all know, just because it hasn't been linked as a relative risk, doesn't mean that it isn't a relative risk. That is my what my previous question relates to... Do you think it will ever be possible to find cause and effect relationships which stand up to rigorous traditional science when we are dealing with such a wide array of individual variability and environmental influences??
    I don't think I agree with your point about mechanics changing- Pathology that may be related to low grade degenerative loading has to reach a point where it becomes symptomatic- the mechanics may not change, and there may not be any change in environment.
    If a high level distance runner developes a pathology after a careful, gradual increase in training load, do you say to them that they can't do that level of training. If you can find an apparent mechanical deficiency, you may be able to help them reach that next level.

    I think I understand your point here, but a finer understanding of mechanics will still allow us to to have a more directed and effective treatment approach- less trail and error.
     
  15. Paul B

    Paul B Active Member

    Hi Craig,

    Yes, a nice plast point. Understanding the mechanics of foot function is important for all of us, but the point in my own mind is, where should the emphasis be placed (chicken or the egg perhaps)?
     
  16. Paul

    Thats a VERY bold statement. I would argue it on several grounds (not least that it's great fun).

    1.
    I would suggest that four things stated above are all factors which will affect the tissue stress threshold. However i do not accept that they are an alternative to variations from the biomechanical norm. In many adult cases i see there is a specific variation AND a generalised reduction in the tissue stress threshold; in many there is a variation without any reduction in threshold and in an unfortunate few, the obese, tapdancing, rheumatoid geriatric patient group i sometimes see pathology without variation.
    2
    Can you point me at some of this research evidence please? And as Craig points out not being able to identify the causal factor does not mean it does not exist! Hence the work Idiopathic, from the greek "we can't find out what the problem is because we're idiots"

    I agree that orthotics all control forces . However i do not feel that this happens "irrespective of biomechanical causal explanation" Firstly the function of an orthotic will depend on the function of the foot. For example put the same orthotic in two patients, one with a medially deviated STJ and one with a laterally deviated STJ and they will behave differently. Secondly "controling forces" is a fairly generalised phrase for what can be a very targeted modality. What forces do you wish to change and how? Stick a medial heel wedge in a patient with a laterally deviated STJ axis and you will increase the supination moments, possibly beyond safe limits. Same wedge in somebody with excessive pronation moments (say because of obesity) but a normal stj axis it will increase supination moments and reduce the residual moment. Same wedge in a patient with a grossly medially deviated stj axis and it will do next to nothing! "controling forces" is, for me, more like steering than braking.

    Regards

    Robert
     
  17. CraigT

    CraigT Well-Known Member

    Nicely put Robert...
    And differentiating where and when you use different techniques should be what a skilled Podiatrist does better than any other health professional.
    As to the 'chicken and egg' question- the emphasis will be dependant on the individual patient, and where along the line of practitioners you see them. For instance- I have worked most of my professional career alongside accomplished Physios and Sports Physicians who may have already diagnosed and begun treatment, so often diagnosis is not needed from myself. It also means that often other causitive factors may have been addressed. This means that I may concentrate more on 'local foot mechanical issues'.
    With the specific diagnostic advances that you describe, I can see the value in being able to differentiate between similarly presenting pathologies. I am mostly interested in first finding the cause(s), so would interested in whether this technology would be able to give some insight here.
    To Paul specifically...
    The 70 subjects of which you speak- Any patterns with the demographic of the people who you are ultrasounding??? Are there more pathologies of certain types seen perhaps with increasing age ? Are there many (or any) U/S dignosed pathologies which are asymptomatic??
    Could be some interesting things there- I have access to the latest MRI, CT, U/s and digital Xray- am very much looking forward to seeing what can be found.
    Cheers!
     
  18. Robert:

    Why do you need to know anything about medially or laterally deviated STJ axes and their effects on the mechanics of the foot and lower extremity?? Don't you know that all you need to be a good clinician is a high definition (i.e. 14 MHz) ultrasound machine to diagnose up to 15 clear and unequivocal cases of disparate foot pathology and not all these useless biomechanical theories and models??!! :eek:
     
  19. Be nice :D . :p
     
  20. A couple of weeks ago in response to a post by Robert I wrote:
    Robert replied:
    A couple of weeks on and Robert writes:
    To which CraigT replied:
    Now THAT's what I call learning ;)
     
  21. I am but a twig of the branch sensai.
     
  22. Robert and Simon:

    This idea that the spatial location of the STJ axis could significantly affect the ability of an orthosis to either supinate the foot or pronate the foot is probably one of the most practical aspects of STJ axis location/rotational equilbrium (SALRE) theory. [And yes, Robert, I am also impressed, as Simon was, of your short learning curve in this regard. Excellent student!!]

    In this regard, I believe that one of the largest shortcomings of the STJ neutral theory is that Root and coworkers never seemed to realize how important the spatial location of the STJ axis is in allowing an orthosis to either pronate or supinate a foot. They did specifically mention its location within the sagittal plane as being either "high pitched" (causing more tibial rotation than calcaneal inversion/eversion) or "low pitched" (causing less tibial rotation than calcaneal inversion/eversion). However, this was pure kinematics, not kinetics. As for the STJ neutral theory, it was pretty much heel bisections, and balancing the heel to vertical. The assumption was that by balancing the heel vertical you somehow "prevented compensations" with the orthosis. It seems almost laughable now in hindsight.

    One cannot understand these concepts without also getting a grasp on moments and rotational equilibrium, which I was never taught at CCPM as a student or Biomechanics Fellow. However, these concepts are basic language for the engineering undergraduate...they just never were introduced into "podiatric biomechanics" until 20 years ago.

    The progress we have made in understanding how foot orthoses work is HUGE. This increase in knowledge is due to us using kinetics-based biomechanical models that have helped us to better appreciate the locations and magnitudes of the internal forces and moments that cause the injuries we treat with foot orthoses and why some patients need more "pronation control features" from an orthosis, for example, in order to see kinematic changes during gait.

    I know that a few of you who have been around for awhile, like Eric Fuller, Simon Spooner and Craig Payne, appreciate these changes that we have been able to make over the past two decades. However, many of you simply haven't been around long enough to appreciate the great strides in biomechanics knowledge that has occurred during this time. It is very significant and our patients have benefited as a result.
     
    Last edited: Jan 28, 2007
  23. markjohconley

    markjohconley Well-Known Member

    god bless the english ............ even if they can't play cricket .. rugby .. football ......
     
  24. Paul B

    Paul B Active Member

    Hi All,

    Just a few quick points.

    Kevin, I’m not sure I appreciate the patronizing tone of your e-mail to Robert which was in fact directed specifically at me. My understanding of these forums is that we promote discussion, debate and dialogue which promote the better care of human foot pathology, so please consider your comments accordingly. The latter comments re importance of understanding for example, axis location, are well understood by most practitioners and probably don’t need to be over-emphasised. Moreover, these observations should not be confused with “causation”. My understanding is there are a subtle, but real distinction between and “associated” finding, and a “causal” finding. Unfortunately, this thread is becoming a little too generalised at the expense of being helpful.

    Robert, your comments of the multi-factorial nature of causation is one I who heartily agree with i.e.;

    I would suggest that four things stated above are all factors which will affect the tissue stress threshold. However I do not accept that they are an alternative to variations from the biomechanical norm. In many adult cases I see there is a specific variation AND a generalised reduction in the tissue stress threshold; in many there is a variation without any reduction in threshold and in an unfortunate few, the obese, tap-dancing, rheumatoid geriatric patient group I sometimes see pathology without variation.

    I am not dismissive of the role the foot mechanics plays, only the “relative importance” it’s given, in the absence of data. Your explanation and understanding of STJ and other axis influence on kinetics etc is the same as mine (and no doubt Kevin’s). The point I’ve posed all along is one of “relative importance”.

    Re Craig’s comment

    I am mostly interested in first finding the cause(s), so would interested in whether this technology would be able to give some insight here.

    I think there’s an old proverb that goes something like this “If a tree falls in a forest, and we don’t see or hear it, dose it make a sound?”. The answer being – probably yes. I’m not sure you necessarily (and I emphasis the word “necessarily”) need to identify a causative factor (proverb above), other than knowing a specific force has been applied to a specific structure resulting in a specific tissue failure. The role of relevant “biomechanical factors” should be accorded appropriately.

    The 70 subjects of which you speak- Any patterns with the demographic of the people who you are ultrasounding??? Are there more pathologies of certain types seen perhaps with increasing age ? Are there many (or any) U/S dignosed pathologies which are asymptomatic??

    The answer is absolutely yes. The patterns of presentation, (age, gender, activity etc etc) are providing a great deal of useful information in the understanding of causality, which is being confirmed by accurate in room real-time ultrasound diagnosis.

    Regards

    Paul.
     
  25. Paul:

    Here is the way you started this thread:
    Patronizing?...I guess that is your opinion....I thought it was appropriate, with my tongue in cheek, considering your statement above. For someone like me that has spent the last 20 years developing new biomechanics theories and, more recently, codeveloping a tissue stress treatment model, your suggestion that a high definition ultrasound machine somehow replaces or improves on biomechanics theories just seems odd and a little funny to me. Maybe you can further explain yourself a little better how a ultrasound machine and biomechanics theories have anything to do with each other. Does the ultrasound machine you use tell you anything about what the magnitudes or types of pathological stresses that are occurring in the foot to cause tissue injury? Does the ultrasound machine tell you anything about the best way to treat the injury that has occurred? Does the ultrasound machine show fracture of bone, or the overall alignment of the foot skeleton?

    Am I not promoting dialogue and debate by contributing to this thread? The comments on these forums may not appeal to everyone, but certainly they will appeal to some. Anyway, Paul, sorry you find my comments patronizing....I have been called much worse and certainly you have the right to your opinion.

    Eagerly awaiting the answers to my questions.
     
  26. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    Gentlemen

    Perhaps allow me to attempt to mediate this discussion with a small interjection of 'perspective'.

    In Australasia, successive government legislation has prevented podiatrists from referring patients for radiological investigations other than plain x-rays, to the extent that a patient may receive a Medicare rebate. It is my opinion that this has contributed to successive generations relying on heavily on clinical skills and biomechanical theory alone to make a diagnosis - particularly for soft tissue injuries affecting ligament, nerve, tendon or muscle. I suspect this is similarly the case in the UK from my observations. This is, I believe, the paradigm that most of the podiatrists outside of the USA work under.

    By contrast, in the USA where Dr Kirby works, podiatrists enjoy the (relative) luxury of being able to order a battery of diagnostic tests to establish a diagnosis. One might say there might be less of a need to rely heavily on clinical testing and biomechanical theory to diagnose many podiatric pathologies (the same could be said for many branches of the medical profession worldwide - who understand no biomechanical theory - yet can 'diagnose' podiatric conditions with high accuracy since "the system" supports them).

    Where does this leave us? Treatment follows diagnosis. Yet understanding the pathophysiology of a condition is what enables targeted therapy (ie a well designed, customised foot orthosis), rather than symptomatic management (rest, behaviour modification and NSAIDs).

    What the rest of the podiatric world outside of the USA needs is better access to radiology and pathology within health care systems, so that the diagnostic process can be confirmed and understood, in tandem with more progress into understanding the pathophysiology/biomechanical theory/causation.

    N'est pas?

    LL
     
  27. Paul B

    Paul B Active Member

    Hi Lucky & Kevin,

    Thanks for both these comments.

    I think Luckys observations are spot on, and probably summarise the situation fairly accurately. Kevins contributions to understanding foot function are well known and appreciated, and as an academic, I teach undergraduate podiatry students about your concepts, along with other explanations of pathomechanics. The point I think you might have missed is and possibly taken out of context, was the diagnostic value of ultrasound which I find is prooving more helpful.............than attributing a foot problem to foot biomechanics theories.

    To expand on this, I would now be undertaking 20 ultrasound investigations (which are yielding far more useful diagnostic information) to every 1 x-ray I order. Another specific example is of the plantar fascia, which we can identify either acute rupture, attinuation, fibrosis, nodule formation etc etc. This is because most pathology we see is foot pain associated with musculoskeletal stress, and the US is simply identifying much more accurately the tissue of interest, and what happening to it. My original question was "where should our emphasis be placed"? Remember, you only have 15 minutes.

    Final question to the forum. Am I the only podiatry practitioner routinely using diagnostic ultrasound in clinical practice?

    Paul.

    PS the comments from:markjohconley re "god bless the english ............ even if they can't play cricket .. rugby .. football ......".. I paid good money to see the poms get slaughtered by the aussies at the one day match at the gabba 2 weeks ago. Oh what a waste of money!!!
     
  28. LuckyLisfranc

    LuckyLisfranc Well-Known Member

    Paul

    I think there is a small smattering of podiatrists and physio's across Australia in private practice who have a decent quality US machine. I have heard one tell me that there are some very cheap and reliable machines now being imported from China that almost make it within the grasp of most practitioners, not just the well-heeled and tertiary institutions.

    The problem boils back to rebates...if there could be a mechanism for billing the service and allowing the patient to claim a reasonable portion, I'm sure there would be a rush from all and sundry to own one. ;)

    LL
     
  29. That is of course your perogative. Personally i had no problem with that Message. I felt it had more to do with definition one than three.

    pa·tron·ize (ptr-nz, ptr-)
    tr.v. pa·tron·ized, pa·tron·iz·ing, pa·tron·iz·es
    1. To act as a patron to; support or sponsor.
    2. To go to as a customer, especially on a regular basis.
    3. To treat in a condescending manner.

    How interesting that the word has three such disparate meanings. I wonder if number three strems from the assumtion that you are in a position to do number one. Personnally i have no problem being informed or corrected by brains of the caliber that this forum attracts although Kevin will confirm that i have dared disagree with him from time to time ;) .I am even willing to undergo a certain amount of condescention and gentle mockery for the priviledge of chewing the fat with such people. (pause for gasps of surprise that people like Dr Spooner would ever mock somebody :eek: :eek: ) For the most part however i notice that things only get nasty when somebody claims that theirs is the ONLY way eg

    To return to the rather stimulating debate,

    I think i see where you are going with this now. If i only get one piece of information then precise diagnosis of injury might well be it. However I don't only have one piece of information nor only 15 mins to assess so in the real world i don't have to choose.

    If your point is that the pendulum has swung too far in favour of the "theoretical" approach and that diagnostics deserves more emphasis i would wholeheartedly agree.
    If your contention is that both approachs are essential to treat effectivly but that the diagnostics have the edge i would agree if you are looking at an exogenic injury and disagree if you are looking at a chronic injury caused by abnormal function.
    The tone (if not the precise wording) of some of your posts suggest that you contention may be that the "theoretical approach" is unimportant and that i would obviously take issue with (as would others)


    ooo Kevin you tease! When might we see this model and who are you developing it with.

    Respectfully

    Robert
     
  30. here's my view for what is its worth, I use lots of biomechanical theories and lots of diagnostic tests/ imaging modalities in an attempt to provide the best possible care (often limited by the financial constraints the patient is under) I can for my patients. To date I have found no biomechanical theory nor any diagnostic tool without fault or limitation.

    Paul as someone with a vested interest in the use of diagnostic ultrasound, I would ask you to try this little exercise: you've told us the good points, now tell us the bad; critically evaluate it's application. What are it's limitations? Moreover, explain how your work improves understanding of "causality"? What methodology are you employing to determine whether something is a "cause" of pathology?

    You call us "poms", only yesterday I heard Australians being described as the "egocentric descendents of criminals". Patronizing or good humour? Depends on your xenophobic point of view... Personally, I try to avoid this kind of descriptor which could be taken out of context.

    I have no idea what you are talking about ;) :p
     
    Last edited: Jan 29, 2007
  31. markjohconley

    markjohconley Well-Known Member

    na simon can't see "edocs" catching on, 2 syllables for one thing, just doesn't flow off the tongue ............. a touch sensitive young simon?
     
  32. Paul B

    Paul B Active Member

    Hi Robert & Simon,

    Thank you for your comments. Thought provoking.

    Re Simons comment : Paul as someone with a vested interest in the use of diagnostic ultrasound, I would ask you to try this little exercise: you've told us the good points, now tell us the bad; critically evaluate it's application. What are it's limitations? Moreover, explain how your work improves understanding of "causality"? What methodology are you employing to determine whether something is a "cause" of pathology?

    I personally have no vested interest in US and like Robert alludes, I also use a balanced approach to investigating and treating common foot pathology, however I have historically adopted the “biomechanical theories” approach up until about 7-8 years ago. My background is in Public Health, Epidemiology & Statistics and my PhD is in developing measurement techniques has moved me beyond this approach now. Pragmatism is the order of the day.

    Moreover, explain how your work improves understanding of "causality"?

    Good question. This is where a soft tissue model of understanding, when combined with the natural history of disease can be well applied, and I give you a very specific example.

    Two 42 year old females present with pain and discomfort in the vicinity of the 2nd met head, duration is approximately 3 months (on and off with a gradual increase in symptoms). There is no known or reported causal mechanism identified by the patient. There is NO obvious oedema on clinical examination, ROM and palpation of the 2nd produces pain and discomfort. Etc etc etc. you know the drill. Now unless we’ve, in the first instance, made a clear differential/diagnosis, it is in my view, it’s less appropriate to commence/justify explanation of this patients pathology by “any” model you chose. Causation cannot be established until we at least know the effect, which can be many and varied. I remind myself we are attempting to establish a relationship, and that takes two.

    These same two patients have undergone real-time US in our clinic and one is identified as having a small tear/rupture of the planter plate, which “opens up” on ROM, and is “seen” on 14 MHz US. You can actually “palpate”, with a small cotton bud applicator, through the plate, onto the inferior aspect of the 2nd met head. Absolutely amazing.

    The other patient, with identical symptoms (pain with weight bearing and activity), when tested with the same ultrasound, demonstrates a completely in tact plantar plate, but diffuse translocation of the collagen fibre matrix (indicating shear forces) with diffuse oedematous plantar fat pad directly beneath the 2nd met head. There are two different soft tissues stressed, to different extents in this example. Two different causal mechanisms (both stress related) both require completely different treatment (repair vs pressure off loading).

    It really is as simple as black (for area of oedema) and white (soft-tissue matrix) as that. One ultrasound test sufficed when X-ray investigation would have produced another NAD.

    Paul.

    PS Simon re "poms" vs "aussies". Can you bat? If so, please buy a plane ticket now. Cheers.
     
  33. Paul:

    I appreciate your comments more now as you explain yourself better. I have no problem with using any diagnostic test that is necessary to give me a better diagnosis for my patient. Diagnostic ultrasound has been used here in the States for over ten years by podiatry and is very popular with some podiatrists that purchase them for their offices. I have used a diagnostic ultrasound unit very little. They seem like they have great potential for better diagnosing many conditions. In addition to taking a history, examining the patient and doing a gait examination, I diagnose my patients by ordering blood and urine tests, x-rays, technetium bone scans, white blood cell scans, CT and MRI scans. I guess diagnostic ultrasound would also be helpful if I didn't have access to an MRI of the patient or if I wanted more immediate diagnosis of certain pathologies.

    However, biomechanics theories and diagnostic ultrasound are really not competing with each other as you suggest. Biomechanics theories tells you how and why the foot works the way it does and how the foot may respond to treatment. The ultrasound machine tells you what anatomical structure may or may not be injured so a diagnosis may arrived at sooner or more accurately. However, I would tend to doubt that a diagnostic ultrasound unit, in my practice, would actually result in my patients receiving better treatment or faster relief of their symptoms, even though it may possibly be useful in a few patients a week to help confirm my suspicion of soft-tissue injury.
     
  34. Dr. Bennett:

    Thanks for providing these case examples. However, realistically, are you going to be suggesting a plantar plate repair surgery for a patient that just has pain, but has no edema or deformity of the 2nd digit but has a small tear in their plantar plate? I sure wouldn't. I would basically treat these two patients initially the same regardless of what the ultrasound (US) showed. However, I will give you that the US has definitely given you a better idea of prognosis and how long to immobilize the plantar plate of the patient with the plantar plate tear versus the patient with no plantar plate tear.

    To me, you do seem to be making quite a leap by stating that the two patients have two different mechanism of injury to their plantar 2nd metatarsal head area simply from the results of their US test. Have you possibly considered that the exact same pathological stress (i.e. excessive compression stress from GRF on the plantar plate and excessive tensile stress on the plantar plate from loading of the plantar fascia) were the cause of both the injuries but that one of your patients simply had a plantar plate that was more resistant to tearing than the other patient's plantar plate??? In other words, how do you know that the patient with "diffuse translocation of the collagen fibre matrix with diffuse oedematous plantar fat pad directly beneath the 2nd met head" was due to shearing stress and not compression and tensile stresses combined??
     
  35. Eric Fuller and I finished writing a chapter for a book nearly two years ago and are still waiting for the book to be published.

    Fuller EA, Kirby KA: Subtalar joint equilibrium and tissue stress approach to biomechanical therapy of the foot and lower extremity. In Albert, S. (ed), Lower Extremity Biomechanics: Theory and Practice, pending publication, 2007?.

    You may see excerpts and preorder the book at:http://www.bipedmed.com/
     
  36. Not really Mark. I just don't think that comments which some people consider as racist are appropriate here. Paul repeating this, doesn't make it better. Perhaps you should both review:
    http://en.wikipedia.org/wiki/Talk:Alternative_words_for_British#Pom_as_offensive
     
  37. Paul B

    Paul B Active Member

    My apologies to Simon. Let me re-phrase my comment;

    "I paid good money to see the English get slaughtered by the aussies at the one day match at the gabba 2 weeks ago. Oh what a waste of money!!!"

    Cheers, Paul.
     
  38. Paul B

    Paul B Active Member

    Hi Kevin,

    I agree with the notion of understanding both the (biomech) and (Dx) aspects of the patients condition and that these are not incompatible (note I use the term not incompatible as opposed to competing), but my sense here in Australia is where the emphasis has been placed.

    This is where we may fundementally differ (which is OK). Its a matter of individual comfort & knowledge/experience. I'm just finding access to this equipment on a daily basis has elevated both my interest & understanding of foot pathology in a way I've not encountered for a number of years. Its reminding me how diverse is the pathology we see, an that there is rarely no one simple answer to the subtle differences we see. Its a bit like surgery, there's little substitution for seeing and fixing frank pathology.

    regards

    paul.
     
  39. Paul B

    Paul B Active Member

    Hi Kevin,

    re the above quote. In the example above the patient was offered conservative orthoses Rx, while they waited for the ultimate surgery they went on to have. The patients outcome was resovled successfully. The odema, and tear, while undersernable on physical examination were in fact present (only on US) and clinically significant.


    Here I'm referring to the tissue stress model, as it applies to two different structures. Anatomically, the dense plantar plate is fundementally different from the plantar fat pad, in both function and design. My understanding is Vertical Ground Reaction Forces (VGRF) will have elements of both compresion and shear, and the individuals (in the above cases) are reacting differently to these forces. So I'm suggesting that unless I was able to make this distinction in the first instance, I'd probably treat them the same way (immobilize) in the first instance.

    Thats where I see the beauty of in office Dx and the soft tissue model being applied concurrently.

    Your thoughts?

    Paul.
     
  40. CraigT

    CraigT Well-Known Member

    I think we are all pretty much on the same page now...
    Going back a step- Paul, do you see any eveidence of flexor plate damage or rupture in asymptomatic subjects??
    I saw a presentation by an ultrasonographer in Melbourne (I think her name is Julie Gregg, but I may be corrected) who had a particular interest in FF ultrasound- she also found that there was a wide range of pathology seen in the forefoot and often in asymptomatic subjects, including multiple flexor plate ruptures. I believe she may have been in the process of writing these findings up.
    My thoughts were that this may be evidence across a whole population of excessive tissue stress...?related to environment, biomechanics... there are many possibilities.
    Perhaps examining under ultrasound a large number of subjects of various age groups may show a pattern in soft tissue degeneration over time. I would suggest this would give some credence to the philosophy of trying to minimise such stresses at an early stage... which would of course be better directed with better biomechanical knowledge!
    Thoughts anyone???
     
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