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. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. 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.

Forefoot Varus Predicts Subtalar Hyperpronation

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Dec 17, 2014.

  1. NewsBot

    NewsBot The Admin that posts the news.

    Articles:
    1

    Members do not see these Ads. Sign Up.
    Forefoot Varus Predicts Subtalar Hyperpronation in Young People.
    Rodrigo Scattone Silva, Ana Luisa G. Ferreira, Lívia M. Veronese, and Fábio V. Serrão
    Journal of the American Podiatric Medical Association: November 2014, Vol. 104, No. 6, pp. 594-600.
     
  2. Rob Kidd

    Rob Kidd Well-Known Member

    Re: Forefoot Varus Predicts Subtalar Hyperpronatio

    All other findings - fine
    Forefoot varus stuff - eyes roll.............................
     
  3. Griff

    Griff Moderator

    Re: Forefoot Varus Predicts Subtalar Hyperpronatio

    Not in agreement with all other findings being fine. Save some of that eye roll for "hyperpronation"...
     
  4. Craig Payne

    Craig Payne Moderator

    Articles:
    6
    My comments:
    1. Unfortunate choice of title re "hyperonation" as that is not what they showed! See the results above; the just compared forefoot angle to some measures of "pronation"
    2. Still have a question over reliability of measurements; but they did repeat them and got an OK response.
    3. The data does not support the conclusion, especially what it says in the title. They correlated the forefoot ankle to pronation parameters and concluded that the forefoot varus predicted "hyperpronation"; as this was a correlational study, it could also be concluded that the "hyperpronation" predicted (?caused) the forefoot varus!
    4. If we accept the construct of 'forefoot varus', then the authors did nothing to distinguish between forefoot varus and forefoot supinatus (see 3)
    5. I am somewhat concerned that ALL the subjects had a "forefoot varus" ... thats got to be a red flag as I would put the prevalence of forefoot varus in the population at around a few %
     
  5. Admin2

    Admin2 Administrator Staff Member

  6. drhunt1

    drhunt1 Well-Known Member

    Not really sure why the "eye roll" when the researchers above discussed hyperpronation. I have found that the forefoot greatly controls the rear foot in gait patterns and static measurements simply don't allow for enough level of predictability when the doc then analyzes the patients' gait. In other words, the amount of pronatory forces observed in gait analysis are typically greater than can be predicted by static measurements alone...and I believe that it is the forefoot that is the over-riding source of this discrepancy. Argue the findings of the study, disagree with the terminology...that's fair. But a forefoot varus deformity is real, (in spite of what some of the US Biomechanics gurus have suggested), and controls the rear foot, (STJ), to a degree that remains, IMHO, unappreciated in our circles. I have changed my perspective on this deformity by trial and error in order to prescribe orthotics that actually work to solve the patients' problems. I now extend the fore foot varus correction to the end of the toes in order to "bring the ground up to the hallux" so that propulsion and balance are improved with these patients. The results have been dramatic.
     
  7. Rob Kidd

    Rob Kidd Well-Known Member

    drhunt1

    You may want to read these, among the many others in the referreed press:

    – Kidd R.S. 1997. Forefoot Varus: real or false, fact or fantasy? The Australasian Journal of Podiatric Medicine 31: 81-86

    – Kidd R.S. 2000. Forefoot Supinatus: Another fictitious pathology, or have we missed the point? Australasian Journal of Podiatric Medicine. 34: 81-5.

    The basis for the so-called forefoot varus, as describe, among others by Root et al is laughable - it has no basis in biology. The supposed aetiology of a failed talar head torsion again has no basis and totally fails to recognise the genuine issue here of peramorphic heterachrony. To be fair to Root et all, they only suggested that it might be due to this, and when I chatted to Bill Orion about this once in The UK, he was quick to point this out. You may like to note how this "supposed" aeitology has been reinterpreted as fact by at least two authors, both from the US - but neither reference their "fact" to any study, of any kind.

    The following is an extract from the Forefoot varus paper (above):

    *************************************************************************

    However, perhaps more seriously, wholesale acceptance of this explanation for talar head torsion is to be found in the formally published works of Seibel (1988) and most recently by Valmassy (1996). Seibel (1988, p166) states

    “The most common aetiology of forefoot varus is failure (ie nonoccurrence or reduced occurrence) of the valgus torsion in the head and neck of the talus during gestation”

    and continues (p 167)

    “The normal valgus torsion of the talar head and neck is responsible for creating a frontal plane arch in the lesser tarsal bones with the concavity plantar...When this torsion fails to occur, the frontal plane arch does not appear either.....”

    Neither statement is referenced (actually, the whole book is un-referenced) so the source of such an apparently authoritative information is not obtainable. That was in 1988; it is disappointing to note, therefore, that the same may be found today (Valmassy, 1996 p63) in which he states

    “It [forefoot varus] is due to inadequate frontal plane torsion of the head and neck of the talus occurring during normal development of the foot".

    **************************************************************************

    This sort of scientific nonsense does podiatry no good, not to put too finer point on it.

    And, in (among several others)

    McPoil T, Cameron JA & Adrian MJ (1987) Anatomical Characteristics of the Talus in Relation to Forefoot Deformities Journal of the American Podiatry Association 77: 77-81

    Note essentially a zero correlation between talar head torsion angle and forefoot-hindfoot alignment - this was before - nearly a decade before, the Valmassy tome.


    I think the modern expression is "cherry picking"...............?

    Never mind the issues of how to measure and establish its existence - static measurements are notorious in their inaccuracy, frequently having errors as large the the object being measured.

    The bottom line is, that while many have problems stomaching it, a true bony forefoot varus is an anatomical rarity - but then, many do not agree with me.

    In my research life I have measured talar head torsion angle on perhaps 3000 human tali, of Southern Chinese, Zulu, Victorian British, Romano British, Pre-contact American Indians from South Dakota, Eskimos from Cagamill Island (Aleution chain) and indigenous Australian. Values are very variable and do not correlate at all with (admittedly coarse) judgements of pedal pathology.

    May I respectively suggest that the place to start is with the late Steve Gould's work on heterchronic modelling? and then apply it to the talus - it works just as well, but in the other direction, with talar neck angle.

    Rob


    Rob
     
  8. Rob Kidd

    Rob Kidd Well-Known Member

    drhunt1

    You may want to read these, among the many others in the referreed press:

    – Kidd R.S. 1997. Forefoot Varus: real or false, fact or fantasy? The Australasian Journal of Podiatric Medicine 31: 81-86

    – Kidd R.S. 2000. Forefoot Supinatus: Another fictitious pathology, or have we missed the point? Australasian Journal of Podiatric Medicine. 34: 81-5.

    The basis for the so-called forefoot varus, as describe, among others by Root et al is laughable - it has no basis in biology. The supposed aetiology of a failed talar head torsion again has no basis and totally fails to recognise the genuine issue here of peramorphic heterachrony. To be fair to Root et all, they only suggested that it might be due to this, and when I chatted to Bill Orion about this once in The UK, he was quick to point this out. You may like to note how this "supposed" aeitology has been reinterpreted as fact by at least two authors, both from the US - but neither reference their "fact" to any study, of any kind.

    The following is an extract from the Forefoot varus paper (above):

    *************************************************************************

    However, perhaps more seriously, wholesale acceptance of this explanation for talar head torsion is to be found in the formally published works of Seibel (1988) and most recently by Valmassy (1996). Seibel (1988, p166) states

    “The most common aetiology of forefoot varus is failure (ie nonoccurrence or reduced occurrence) of the valgus torsion in the head and neck of the talus during gestation”

    and continues (p 167)

    “The normal valgus torsion of the talar head and neck is responsible for creating a frontal plane arch in the lesser tarsal bones with the concavity plantar...When this torsion fails to occur, the frontal plane arch does not appear either.....”

    Neither statement is referenced (actually, the whole book is un-referenced) so the source of such an apparently authoritative information is not obtainable. That was in 1988; it is disappointing to note, therefore, that the same may be found today (Valmassy, 1996 p63) in which he states

    “It [forefoot varus] is due to inadequate frontal plane torsion of the head and neck of the talus occurring during normal development of the foot".

    **************************************************************************

    This sort of scientific nonsense does podiatry no good, not to put too finer point on it.

    And, in (among several others)

    McPoil T, Cameron JA & Adrian MJ (1987) Anatomical Characteristics of the Talus in Relation to Forefoot Deformities Journal of the American Podiatry Association 77: 77-81

    Note essentially a zero correlation between talar head torsion angle and forefoot-hindfoot alignment - this was before - nearly a decade before, the Valmassy tome.


    I think the modern expression is "cherry picking"...............?

    Never mind the issues of how to measure and establish its existence - static measurements are notorious in their inaccuracy, frequently having errors as large the the object being measured.

    The bottom line is, that while many have problems stomaching it, a true bony forefoot varus is an anatomical rarity - but then, many do not agree with me.

    In my research life I have measured talar head torsion angle on perhaps 3000 human tali, of Southern Chinese, Zulu, Victorian British, Romano British, Pre-contact American Indians from South Dakota, Eskimos from Cagamill Island (Aleution chain) and indigenous Australian. Values are very variable and do not correlate at all with (admittedly coarse) judgements of pedal pathology.

    May I respectively suggest that the place to start is with the late Steve Gould's work on heterchronic modelling? and then apply it to the talus - it works just as well, but in the other direction, with talar neck angle.

    Rob


    Rob
     
  9. drhunt1

    drhunt1 Well-Known Member

    Rob Kidd-One of the promptings that I have learned in my career is that physicians tend to make our "science" much more complicated than it really is. Both my father and grandfather were accomplished MD's that truly thought things through on their own, using their own experiences to lead them through the clinical machinations that patients can present in clinical settings and using their education, yes, but also their gut instincts to successfully treat. That being written, we don't function in a vacuum, instead, we utilize other research to fine tune our own instincts based on our own experiences. Podiatry doesn't lend itself to evidence based medicine as easily as other medical disciplines. As an example, where have we witnessed a serial radiographic study of the same patient through childhood into an adult? Some of the pathologies we treat take decades to form, yet we view these problems as a snapshot and few Podiatrists practice our profession much more then 30 years.

    When I refer to a forefoot varus deformity, I have now determined that it is much more reasonable and worthwhile information to avoid concern about talar torsion and focus on the relationship of the forefoot to the ground. We can all accept that the hallux is critical in propulsion and balance, so we can all accept that the foot will react to GRF in order to bring the hallux in contact with the supporting surface. If the forefoot is sufficiently inverted to the supporting surface, then the oblique and long axis of the MTJ, and then eversion of the STJ will function to bring the hallux into contact with the ground. Does it make sense to have an orthotic end behind the first MPJ if the hallux doesn't gain purchase? Calculating a forefoot to rear foot relationship, IMHO, is perhaps not as important as determining what the GRF does to the foot, (or how the foot responds to GRF). By strict definition then, I have expanded the definition of forefoot varus to include the relationship of the ground to the forefoot. While it may not be "kosher" in the academic community to do this, it makes sense to those in private practice that have difficulty determining why the orthotic is not achieving the desired results.
     
  10. Rob Kidd

    Rob Kidd Well-Known Member

    Interesting thoughts; at least we have something in common - my father and grandfather were also accomplished physicians - indeed my Grandfathers cousin was Tom McMurray - as in McMurrray's osteotomy of the hip - but then - the past is the past and the present is the present. Actually, three of my four Grandparents were medically qualified; my grandmother was famous in her day for taking apart a pair of Siamese twins in utero with a giggly saw under ether anaesthetic - but that is another story altogether.


    I do not except that podiatry is any different from any other therapeutic discipline in its need to apply scientific method to its practice - this is, after all, the basis for evidenced based medicine. I do not have an opinion about orthoses and their design - I leave that to those who currently practice. While head of school in Sydney, about 15 years ago, one of my staff did his PhD on orthosis design and a randomised trial with concern to heel pain; I would always defer such conversations to him and others like him.
     
    Last edited: Dec 22, 2014
  11. drhunt1

    drhunt1 Well-Known Member

    Rob Kidd-thanks for the reply. Indeed, we have some things in common. Your experience with doctors as you grew up as a child might be similar to mine, and you might agree, then, that physicians tend to complicate medicine when in discussions with each other, and oversimplify these same concepts when in discussion with our patients. The medical literature is replete with the research, all well intended, on biomechanics of the foot. Many of those articles, IMHO, leave the practitioner scratching his head wondering how that relates to improving his/her own performance in orthotic prescriptions. Instead of making the concept of orthotic control so unwieldy, perhaps we should attempt to simplify the information so that even cavemen, like myself, can understand it. It has been my experience that Podiatrists here in the US, to a great degree, have "given up" on biomechanics and we have seen Physical Therapy and even Chiropractic Medicine intervene. Let's examine what Evidence Based Medicine entails:


    "Evidence based medicine is the conscientious, explicit, and
    judicious use of current best evidence in making decisions
    about the care of individual patients. The practice of evidence
    based medicine means integrating individual clinical expertise
    with the best available external clinical evidence from systematic
    research. By individual clinical expertise we mean the
    proficiency and judgment that individual clinicians acquire
    through clinical experience and clinical practice."

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2349778/pdf/bmj00524-0009.pdf

    Three years ago I began to create a program that addresses growing pains in children and have made the biomechanic/anatomic link to restless leg syndrome in adults. My hypothesis is that the two are a continuum of the same problem. I hired an animator, (two actually), a videographer, and an illustrator. The text was 10K words long and 42 pages in length and the patient interview/animation portion was almost an hour in length. The animation is cutting edge, IMO, and needs to be expanded upon in order to teach students and practitioners of our science an easier way to learn how to control foot function. I had planned on submitting the program for CME units, but was met with incredible road blocks from our own community. I reduced the program to 3K words without the videos, illustrations and jpegs for quick submission/publication in a non PubMed Journal. More on this later. I'm a minimalist, I suppose...but came to the conclusion that doctors cannot, as a whole, visualize in 3D. Animation bridges that gap.

    Happy Holidays and Merry Christmas...
     
  12. Jeff Root

    Jeff Root Well-Known Member

    I don't understand why the concept of forefoot varus or valgus is so difficult to appreciate. In the traditional (plaster-of-Paris) construction of a functional foot orthotic, we convert a negative cast into a positive cast by filling the negative cast with plaster. When we set the positive cast on the counter, one of three things will happen. The cast will rest with the heel inverted, vertical or everted. The heel moves in the opposite direction as the plane of the forefoot since the forefoot will rest parallel to the supporting surface. Hence, a cast of a foot with a forefoot varus will rest with the heel everted and a cast of a foot with a forefoot valgus will rest with the heel inverted. And a cast with no forefoot varus or valgus will rest with the heel vertical.

    By definition, forefoot varus and forefoot valgus are assessed with the stj in the neutral position and the mtj fully pronated. While one can debate the accuracy of heel bisections, inverted and everted forefoot conditions become readily apparent when dealing with negative and positive casts of feet and are easier to appreciate (visualize) when they are more extreme.

    Variability in the positioning of the stj and the mtj by practitioners can influence the apparent amount of (degree of) forefoot varus or valgus in a cast. If the forefoot is not fully pronated (especially fully everted) during casting, then this will result in a less everted or a more inverted ff to rf angle. If the stj is pronated during casting, the mtj will develop and increased rom in the direction of pronation (eversion) and this will result in an increased degree of forefoot valgus or a decreased degree of forefoot varus in the resulting cast. If the stj is supinated during casting, the range of pronation at the mtj is decreased which will result in a decreased degree of forefoot valgus or an increased degree of forefoot varus in the resulting cast.

    In the practical application of biomechanics, an orthotic laboratory cannot simply dismiss the structural and positional factors that influence the three dimensional contour of the model that we use to fabricate a functional foot orthotic. In fact, we must incorporate these contours in the shape of the orthotic shell or we must alter the positive cast in order to intentionally alter these 3D contours and thereby alter the resulting shape of the orthotic shell. In spite of margin of error factors and practitioner variability during casting, we are far better served using terminology which describes the forefoot to rearfoot relationship seen and measured in a cast of the foot than we are ignoring it since it is a physical reality demonstrated in the 3D contour of the cast.

    Jeff
     
  13. Doogle

    Doogle Active Member

    With respect Dr Root, the forefoot to rearfoot relationship is not so much a difficult concept to grasp, but rather an outdated and irrelevant one as it can`t determine cause of pathology.
     
  14. drhunt1

    drhunt1 Well-Known Member

    Doogle-I don't agree. Evaluation of the forefoot to rearfoot and comparison of the bisected posterior calcaneus in static stance vs. neutral position is an important tool for determining the Rx when ordering orthotics. It is also a good learning tool for young practitioners early in their careers to grasp biomechanic measurements until a "well trained eye" can be justifiably trusted. When an orthotic is ordered, and is not satisfactory in resolving the patient's complaints, and therefore has to be re-ordered...who pays the second set...the patient...the lab? No...it's the doctor who ordered it and made some mistakes on the Rx because he/she didn't take the time to figure it out originally. In California...Blue Cross PPO pays $175 for a pair. If the lab fee is $65-80/pair, one can see where this would lead, even if the patient is billed for the remainder of the bill from the doc. Accuracy is VERY important...if for no other reason than the financial consideration.
     
  15. Doogle

    Doogle Active Member

    Thanks for replying. Yes i am a young practitioner and am very grateful for your advice. I still do not see measuring a static foot in will help in orthotic prescription. We are taught to reduce the load of what is hurting when the person walks, not work for financial consideration. Maybe it`s different in the UK welfare state, I just want to make the patient better.
     
  16. Jeff Root

    Jeff Root Well-Known Member

    What has financial consideration got to do with anything that has been said?
     
  17. Jeff Root

    Jeff Root Well-Known Member

    Doogle,

    The Sharp Shape CAD/CAM orthotic manufacturing system is the most common commercially available system on the market. One must determine the inverted, vertical or everted angle of the heel during the orthotic manufacturing process. This will determine the amount of forefoot varus or valgus (or no ff angle) present in the cast or scan of the foot. The angle of the ff to rf significantly influences the contour of the device. The practitioner, via the Rx can determine the amount of intrinsic or extrinsic rearfoot and forefoot correction (angle) to put into the corrected device. Even if the practitioner doesn't care about ff to rf, the lab has use it in manufacturing! I'm not suggesting that you have to use this approach, I'm simply trying to educate you as to how over a hundred thousand doctors have used ff to rf in the production of over a million pair of orthoses over the past forty years.

    Jeff
     
  18. Doogle

    Doogle Active Member

    Wasn`t me!

     
  19. Jeff Root

    Jeff Root Well-Known Member

    I think he means so the doctor doesn't have to pay out of pocket for another pair due to his/her own fault (i.e. a bad orthotic). Keeping unnecessary expenses down is in the patient's best interest.
    Jeff
     
  20. drhunt1

    drhunt1 Well-Known Member

    Doogle/Jeff Root-precisely my point. An orthotic that does NOT help the patient requires another set to be made and here in the States, that cost has to be eaten by the doc. Not really sure how socialized medicine functions in the UK, (I am afraid I will find out shortly), but better outcomes is in everyone's best interest...particularly the patient. Doogle-when assessing a patient's complaints, it is incumbent on the practitioner to determine the cause of that pain and any over-riding reason it exists. For instance, a patient presents to you with heel pain caused by excessive pulling of the plantar fascia on the calcaneus. This is a very common problem that we see/treat everyday. If one is not careful in determining the underlying reason, eg., a forefoot varus leading to a hallux limitus secondary to a metatarsus primus elevatus deformity, the prescribed orthotic may not resolve the patient's complaints entirely. Some patients are flexible enough to have the practitioner reduce the elevated first met at the time of casting. In other patients with a more rigid forefoot, this simply won't work. By comparing resting calcaneal stance position to neutral calcaneal stance position, the doc can gain an idea of the severity of the deformity, thus improving the prescription correction. A calcaneal bisection can greatly assist the practitioner in determining the degrees of correction...all, of course, IMHO.
     
  21. Jeff Root

    Jeff Root Well-Known Member

    Today I happened to cast a local Podiatrist. Here are pictures of his casts. You can clearly see his negative casts rest with the heel inverted due to his everted (valgus) forefoot condition. In the lab, we will have to determine what frontal plane position to place the heel in when we make his orthoses. We can use the heel bisection to measure the degree of forefoot valgus in his feet. We can also use it to place his heel in an inverted, vertical or everted position when we manufacture his devices. I'm posting these pictures in an effort to demonstrate the practical application of forefoot to rearfoot relationship in orthotic fabrication.
    Jeff
     

    Attached Files:

  22. Rob Kidd

    Rob Kidd Well-Known Member

    I cannot help but feel we have been around this before - and more than once. Be quite clear, what you have in front of you there is NOT the bony forefoot-hindfoot relationship. It is the soft tissue bag that surrounds the bony forefoot-hindfoot relationship. For this to represent truly the Forefoot-hindfoot relationship, you would first have to demonstrate that the soft tissue contours follow the bony structures within. They do not; the extrapolation of one to the other in invalid.

    The very basis for the Forefoot varus "myth" (and I do note that these are not "forefoot varus" casts) lies in the bulge of tissue medially at the heel in a non-weightbearing, pronatory foot - eg a rearfoot varus.

    Rob
     
    Last edited: Dec 23, 2014
  23. Jeff Root

    Jeff Root Well-Known Member

    Rob,

    Don't you think that the large medial tubercle on the plantar, medial surface of the calcaneus influences the plantar contour of the medial heel? Also, don't you think that osseous conditions such as a plantarflexed 1st metatarsal or first ray create or contribute to the everted (valgus) position of the forefoot?
    Jeff
     
  24. I debated with myself of even getting into this discussion since this is a stump we have gone around so many times over the past two decades here on Podiatry Arena and the old JISC Podiatry Mailbase that I simply lost track.

    However, since this an important subject, here are the facts.

    1. Yes, an inverted forefoot deformity (i.e. forefoot varus or forefoot supinatus) does exist. However, whether an inverted forefoot deformity exists or not in any individual foot depends very much on how the examiner draws the heel bisection line, how they find subtalar joint "neutral position" and with how much manual force they use to dorsiflex the lateral column during examination. Therefore, the presence of inverted or everted forefoot deformity is very much examiner dependent.

    2. We do not know how to determine whether a inverted forefoot deformity is a congenital (i.e. a "true" forefoot varus) or an acquired (i.e. an acquired forefoot supinatus) deformity.

    3. Since the presence or absence of a inverted forefoot deformity varies so much from one examiner to another, then this fact, by itself, makes if very difficult to discuss this "deformity" as a "cause" of foot pathology. There is simply too much inter-examiner error in determining forefoot to rearfoot relationship.

    4. The idea that inverted forefoot deformity is caused by some frontal plane torsion of the talar head and neck makes no biomechanical sense and, from my recollection, was never promoted either by Drs, Mert Root or John Weed as being a fact that was supported by the existing literature of the time.

    5. Any practitioner that relies heavily on the determination of a "forefoot deformity" to determine their patients' orthosis prescriptions has missed out on the last two decades of podiatric biomechanics theory development where Tissue Stress Theory has become the most widely accepted method of designing custom foot orthoses.

    Merry Christmas!:santa:
     
  25. Rob Kidd

    Rob Kidd Well-Known Member

     
  26. drhunt1

    drhunt1 Well-Known Member

    Kevin-as much as I agree with many of the points you make, the fact that this "issue" is so frequently re-visited indicates gaping holes in our understanding. When I read the foot function research of others, I'm usually skeptical of their ability to separate the wheat from the chaff in re to foot function when their expertise lies outside of the realm of Podiatry. We view this anatomical structure on a daily basis...many of them do not. Does this mean I completely disregard their findings? Certainly not. But when their conclusions fly in the face of what I view in my practice, I am less apt to adhere to their research, and use my "evidence based" models instead. One thing I have concluded is 1) the human body cannot fight gravity and 2) the need to bring the hallux into complete contact with the supporting surface. While soft tissues can attempt to correct for structural deformities, in the end, they will "lose" to the forces of gravity darned near every time. When I see a 15 y.o. patient in my office with hammertoe deformities my main concern is why. Is this an example of flexor substitution of the FDL because the hallux is not providing enough propulsion? More times than not, it is. Thus, the soft tissues are attempting to correct for osseous deformities in the ongoing battle between gravity and genetics.

    And a very Merry Christmas to you, as well.
     
  27. One other important point that I left out of my last post is that the frontal plane alignment of the forefoot to the rearfoot is not an unalterable "deformity" that changes little over a patient's life. Rather, I believe that the frontal plane alignment of the forefoot to the rearfoot always is affected by both structural and acquired changes in joint position. In other words, forefoot to rearfoot alignment, whether perpendicular, inverted or everted, will change over the lifetime of a patient and will change depending on the prevailing external and internal forces acting on the foot and lower extremity throughout an individual's lifetime.

    When excessive subtalar joint (STJ) pronation moments are acting on the foot over a period of days, weeks or months, the increased dorsiflexion moments on the medial metatarsal rays will tend to cause an elongation of the plantar retaining ligaments of the medial column which will tend to, over time, cause either an increase in "forefoot varus deformity" or a decrease in "forefoot valgus deformity".

    Conversely, when excessive subtalar joint (STJ) supination moments are acting on the foot over a period of days, weeks or months, the decreased dorsiflexion moments on the medial metatarsal rays will tend to cause a shortening of the plantar retaining ligaments of the medial column which will tend to, over time, cause either an increase in "forefoot valgus deformity" or a decrease in "forefoot varus deformity".

    I have seen both of these phenomena occur over time in my patients over the last three decades of practice on quite a few occasions and I consider these observations to be due to the viscoelastic nature of the retaining ligaments and other structures of the foot and lower extremity. As a result, I now consider the forefoot to rearfoot relationship to be somewhat of an indicator of the prevailing STJ moments have been acting on that patient's foot over their recent weightbearing history.

    Forefoot to rearfoot relationship within the frontal plane should, therefore, not be thought as just a structural "deformity" of the foot. Rather frontal plane forefoot to rearfoot relationship should rather be thought to be a indicator of the prevailing forces that have occurred on that foot over that individual's recent lifetime which is dependent on the load/deformation response of the viscoelastic structures of the foot to changes in forces over time during weightbearing activities.

    Merry Christmas everyone!:santa::santa2::drinks
     
  28. Jeff Root

    Jeff Root Well-Known Member

    I completely agree with you Kevin! Your reasoning is exactly why I have repeatedly written on this site and the old podiatry mailbase about how functional orthoses can alter forefoot to rearfoot relationship by reducing plantarflexed 1st ray deformities and forefoot supinatus.
    Jeff
     
  29. And the increased force under the 1st metatarsal segment and hallux created by an extended forefoot varus wedge/ post will increase the dorsiflexion moments on the medial metatarsal rays and will tend to cause an elongation of the plantar retaining ligaments of the medial column which will tend to, over time, cause an increase in "forefoot varus deformity" -Restating the obvious Kevin, but I felt your post might have been too subtle for some...

    Sleep tight in the knowledge that your intervention of a forefoot varus post extended beneath the hallux is likely to be increasing the inversion of the forefoot on the rearfoot in such individuals, Dr Hunt (your first name's not Michael by any chance?).


    Yep, that's never a good motivation.

    Merry Christmas.
     
  30. rdp1210

    rdp1210 Active Member


    1. I agree with the first 4 points that Kevin has made. His last statement I really question. A majority of podiatrists are not using tissue stress to design orthotics. I use STJ axis theory as part of my design, but I have no idea how tissue stress helps design a custom foot orthosis. If Kevin or Eric Fuller tell me that they no longer cast most of the feet using the Root casting technique, then I may believe that another theory has replaced Root.

    2. As I have reviewed and contemplated the old literture, I have come to recognize that Root basically took the Steindler concept from 1929, and adapted it to an inside the shoe device. You'll remember that Steindler corrected flat feet by putting a varus wedge on the heel of the shoe and a valgus wedge under the fore part of the sole. Root came along and said, let's adapt the semi-weightbearing molds we've been doing and a) increase the varus torque on the heel by taking a NWB cast to increase the pressure against the medial heel (pre-Kirby skive), and b) maximally pronate the forefoot against the rearfoot in our casts, again by doing a NWB cast. Anyone who has played with Root orthotics knows that orthotics made without both of these criteria are not as successful.

    3. Having been in the goniometer design process for many years (there are some papers about the reliability of the Phillips Biometer), I have greatly pondered the idea of a calcaneal bisection line. What is it and why do we use it? And I always come back to that same question -- why would anyone want to bisect anything? Unfortunately no one has really approached the calcaneal bisection from an engineering standpoint. I would propose defining the posterior bisection line with the following criteria (-- I don't want to hear those who stand on their own philosophical or EBM soapbox and decry the need for it -- lets just get to the laboratory.)
    a. should be overlying the center of mass of the os calcis.
    b. should overlye the center of the weightbearing surface of the calcaneal fat pad.
    c. when it is vertical, the inversion and eversion moments on the os calcis should be equal.
    (Note: the calcaneal bisection line is a reference line. It should not be confused nor mixed with the subtalar joint axis. That is a totally different subject.)

    4. I will agree with Craig Payne, that the paper in this discussion is a correlation paper, not a cause and effect paper.

    5. Varus deformities of the forefoot were well recognized before Root. You'll recall that Perkins (1948) proposed a surgical correction for forefoot varus. Cotton also proposed a surgical correction, long before Root. What Root did was to try to standardize the methodology for measuring the forefoot varus. Unfortunately he did not standardize the force against the forefoot, and we still haven't. Howard Hillstrom and Jinsup Song have done some work on this, but haven't published anything yet. I believe that the future of forefoot-rearfoot measurements will be in constructing a forefoot-rearfoot stiffness curve for each individual, not in just a single static measurment.

    6. Anyone who has done any number of goniometric examinations knows that there are high arch feet that have measured forefoot varus and low arch feet that have measured forefoot varus. The shapes vary considerable, so that in itself would argue that there are multiple types of inverted forefoot deformities. The rotation of the talar neck was first proposed by Hlavac (1971). The McPoil paper and also the more recent paper by Lufler (2012) point to the fallacy of the the Hlavac proposal. Unfortunately, neither of these studies are in living subjects, so post-mortem changes may be a counfounding variable. New CT technology now opens up a world of research into the etiologies of forefoot varus.

    With that said,
    Merry Christmas to all, and to all a good night. See y'all in 2015
     
  31. Hi Daryl,
    I know you specifically asked for Kevin or Eric, but I'd like to pitch in if I may? I specifically cast the foot in a postition which I believe will minimise the amount of work I have to do to the positive model in order to create a foot orthoses that has the surface topography that I believe will decrease the forces on the injured tissue, e.g. if I want to increase the forces under the lateral forefoot with my orthoses, I will tend to plantarflex the first ray in casting, if I want to increase the forces under the lateral rearfoot, I might pronate the rearfoot during casting. Both of these modifications I might use for a patient with chronic lateral ankle instability, or peroneal tendonitis, or medial compartment knee O/A. As I'm sure you understand, casting is all about shape of the product and the change in force distribution that can be achieved with this approach. To this end, I also change material stiffness within the shell in an attempt to enhance the influence of shape alone- to decrease the stress on the injured tissue through modification of external moment via the foot orthoses. I have found this to be the most efficacious approach. We have to think in 4D though.


    Here's a good opportunity for learning for all, it's Christmas, a time for giving:

    Pick a tissue within the foot that has been injured due to mechanical overload, Daryl. Lets see if between us all we could come up with the casting position which could enhance the design characteristics for a foot orthosis that might relieve the stress on that tissue... everyone game?

    I just had a thought, I could probably write a book on the casting positions I employ for different pathologies. However, since I hate writing and I'm generally lazy, I'd be better off planting that seed in the head of my mentor and hopefully inspiring him to write a series of newsletters on the subject in 2015- thanks Uncle Kevin.

    Hands up all those that plantarflex the forefoot on the rearfoot, invert the rearfoot, evert the forefoot on the rearfoot and plantarflex the first ray when casting for foot orthoses for Achilles tendonosis? Can I provide a theoretically plausable reason for this? You bet your mothers ass...


    Happy New Year and best wishes,
    Simon
     
  32. drhunt1

    drhunt1 Well-Known Member

    Simon Spooner wrote:

    1) And the increased force under the 1st metatarsal segment and hallux created by an extended forefoot varus wedge/ post will increase the dorsiflexion moments on the medial metatarsal rays and will tend to cause an elongation of the plantar retaining ligaments of the medial column which will tend to, over time, cause an increase in "forefoot varus deformity"

    2) Sleep tight in the knowledge that your intervention of a forefoot varus post extended beneath the hallux is likely to be increasing the inversion of the forefoot on the rearfoot in such individuals, Dr Hunt (your first name's not Michael by any chance?).

    While most times I would disregard such ignorance on any other forum, I feel compelled to respond to these statements on a PROFESSIONAL forum frequented by doctors from around the globe. I'm not really sure which of the two statements are more moronic...the first or the second. The first statement is a gobbledy gooked, run on sentence which "may" make sense if all we were discussing was flexible deformities, but does not, nor ever will address structural pathologies. Please read my posts above.

    The second statement is what I would expect from a young high school student, (is that what you are, Simon?), certainly not from a doctor from any country on a public forum. Your lack of professionalism is only superseded by the dogmatic ignorance you displayed. As I wrote above, I have uncovered the root cause of growing pains in children...a medical dilemma that has perplexed practitioners for 191 years. And as I wrote above, I have linked GP in children to RLS in adults. This article hopefully will be published in Jan/Feb...with more to come following that release. Let me know when, with your eminent intelligentsia, you have resolved an issue of such importance, effecting millions of patients worldwide/year with your way of diagnosis and treatment. Until then, Simon...best of luck.
     
  33. drhunt1, whoever you really are (it would be nice to know your real name), I really see no problems with Dr. Spooner's comments. His first statement, rather than being "gobbledy gooked" makes complete sense to me. However, your comment that Dr. Spooner's statement ""may" make sense if all we were discussing was flexible deformities, but does not, nor ever will address structural pathologies", does not seem to make any sense to me.

    His second statement, if you knew Dr. Spooner like I do, is likely in response to your statements in earlier postings where, out of the blue after just joining Podiatry Arena, you said:

    Really, drhunt1, the "forefoot greatly controls the rearfoot"?! Do you think you are telling us something new and enlightening that we haven't already discussed in great detail over the past ten years here on Podiatry Arena. Dr. Spooner, Eric Fuller, Craig Payne, Howard Dananberg and many other very knowledgeable individuals have been hashing out these ideas here on Podiatry Arena for many years. Maybe you would want to look at the archives before you burst on to this academic website and start telling us how you "bring the ground up to the hallux" like it is something we haven't already been talking about and arguing about already for years and years.

    I am, however, interested in your research. Which peer-reviewed journal will it be published in. I will be interested to see if it is as ground-breaking in nature as you make it out to be in that you "have uncovered the root cause of growing pains in children...a medical dilemma that has perplexed practitioners for 191 years." Since growing pains is something I lecture on and have written on for years, I await to be enlightened.
     
  34. rdp1210

    rdp1210 Active Member

     
  35. I use Root's basic negative casting technique for less than half of my patients, I modify it for the rest of my patients. So I suppose I don't follow Root's casting technique for most of my patients. But, Root wasn't the first to describe plaster strip casting of the foot in the medical literature for foot orthoses. I believe that honor belongs to an orthopedic surgeon named Edward Reed (Reed EN: A simple method for making plaster casts of feet. JBJS, 17:1007, 1933) who described the technique nearly four decades before Root's book on negative casting (Root ML, Weed JH, Orien WP: Neutral Position Casting Techniques, Clinical Biomechanics Corp., Los Angeles, 1971).

    I commonly use forefoot extensions in my foot orthoses, which is something that Root discouraged in his lectures I attended.

    I commonly use medial and lateral heel skives, which is something that Root never talked about or wrote about.

    I commonly use subtalar joint axis spatial location to determine orthosis prescription which is something Root didn't seem to fully grasp, and, if he did, he never wrote about it.

    I don't rely on subtalar joint neutral measurements as advocated by Root to determine my orthosis prescription. Rather, I use the location of tissue injury to determine my orthosis prescription which is something I never heard Root lecture about or saw that he wrote about. Root advocated making the same orthosis for a patient with posterior tibial tendinitis and another patient with peroneal tendinitis as long as the "foot deformities" of the two patients were the same.

    I don't mind balancing my foot orthoses inverted regularly which Root only "allowed" in certain instances.

    I don't believe or teach that heel vertical is "normal", that subtalar joint neutral is "normal" or that the midtarsal joint has just two coexisting axes, as Root taught.

    I don't believe that calcaneal bisection is easy to replicate from one practitioner to another as Root taught.

    I don't believe that forefoot to rearfoot measurements are easy to replicate from one practitoner to another as Root taught.

    I don't believe that foot orthoses need to be made of thermoplastic or inherently rigid material to be a "functional orthosis" as Root taught. Rather, for the past three decades I have been teaching that cork and leather and plastazote shank dependent orthoses can be just as much a "functional orthosis" as one made out of Rohadur that ends at the metatarsal necks as Root advocated.

    I do appreciate all that Mert Root taught me and has done for our profession. However, I don't need to bring his name up every time someone talks about foot and lower extremity biomechanics. I acknowledge Root's genius, but have no problems proposing new theories and new techniques which refute much of what Root taught, all for the good of our profession. In other words, I don't feel the need to continually try to defend Root about what he thought and did, as you nearly always do. I am ready to move on, acknowledging what everyone (and not just Mert Root) has contributed to our knowledge base before us so that we can improve on our theories and treatments.

    In other words, Daryl, I believe we should all be eager to move on ahead of what Root taught our profession so that our profession may stay at the forefront of foot and lower extremity biomechanics and custom foot orthosis therapy and not be left behind, lagging behind other professions because we are too busy trying to defend the memory of Mert Root, than proposing newer, better theories and newer, better treatments for our patients with mechanically-based foot and lower extremity pathologies. Let's give credit to Mert Root for what he did, but not put him on some sort of pedestal where he doesn't belong and, likely, if he were still around today, would not want to be placed. Like Mert Root before us, I want nothing more than to be given due credit from those who will be telling "our stories" when we pass on from this life, Daryl.

    Merry Christmas.:santa::drinks
     
  36. Jeff Root

    Jeff Root Well-Known Member

    Kevin, Root's work was a work in progress. I'm glad to see that yours is too and that you are not frozen in time.
    Jeff
     
  37. Here you go Daryl, a Christmas present from me to you, here is an FEA for a polyprop device loaded with input data obtained from an F-Scan. It's not just when you step on it, the shape is dependent upon where you are within the step.
     

    Attached Files:

  38. Jeff,

    Mert Root was a truly great man. I know that his work was a work in progress. For him to do and accomplish what he did, with the limited resources available to him, and with so little biomechanics research to learn from at the time, was a remarkable accomplishment. For all of his contributions to our knowledge, I will remain eternally grateful.

    However, as you know, the 21st century is a different era from the late 20th century. As such, we can't rely on the past but, instead, we need to move forward as a profession. Our very existence as a profession depends upon it. I'm sure you share my feelings on this matter. See you in Vancouver!

    Merry Christmas to you and your family.:santa::drinks
     
  39. Jeff Root

    Jeff Root Well-Known Member

    Kevin,

    Unfortunately neither biomechanics nor orthoses have any real appeal to the younger generation of podiatrists here in the U.S. Why? Your work will be used by CPeds in the future. They see the void left by podiatry and are quickly modifying their education to take advantage of it. They have a lot of catching up to do but given the current climate, they will likely take over this area of "treatment" even though they are not medical practitioners.
    Jeff
     
  40. rdp1210

    rdp1210 Active Member

    Love it, Simon. Exactly what I've been saying for quite a while, the shape of the orthotic is constantly changing. This is the stuff we need more of!!

    Daryl :santa:
     
Loading...

Share This Page