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Occam's Razon or the Law of Parsimony

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Brian A. Rothbart, Nov 3, 2021.

  1. P. 27 Root, Orien and Weed: Normal and abnormal function of the foot: “because of the frontal plane torsions associated with normal and abnormal ontogeny…” etc.

    while you in: Lambrinudi is credited with first describing metatarsus primus elevatus in 1938 and William Sayle-Creer had given an account of the compensatory mechanics and treatment in 1943.

    seems there is nothing new under the Sun…

    we do have data which disproves the hypothesis of Talar torsion being related to forefoot position: Lufler et al. 2012: anatomical origin of forefoot varus malalignment. JAPMA; not aware of any quality research which supports it
     
  2. scotfoot

    scotfoot Well-Known Member

    I sense you are starting to bob and weave .

    I am simply asking ,if Roots foot types are the "result embryological ontogenetic development of the fetus " would that make them the same as yours ? A basic and fair question .
     
  3. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    I answered this question in detail. But to reiterate:

    Root's foot types are constructs, that from an embryological point of view, do not exist. Specifically, using Root terminology:
    1. Rearfoot Varum cannot exist alone, it could only occur concomitantly with Forefoot Varum (this is explained in the linear ontogenetic development during fetalgenesis)
    2. Forefoot Varum, an inversion of all 5 metarsals, is an impossibility because Mets 2-4 are modeled by the ontogenetic development of the cuboid.

    Is there something in the above that you require further explanation/clarification?
     
    Last edited: Nov 19, 2021
  4. scotfoot

    scotfoot Well-Known Member

    Then how do we get to them ?
     
  5. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    I agree, Lambrinudi was the first to describe Metatarsus primus elevatus. I believe I was the first to describe Primus Metatarsus Supinatus. Elevatus is not the same as supinatus.

    I am familiar with Lufler position. And he is correct in that talar torsion does not model forefoot varus malalignment. Talar torsion models only the embryological medial column of the foot, which is not the same as forefoot varus (mets 1-5).

    Embryological foot plates through Carnegie Stages 24 demonstrate that the unwinding of the talar head and neck, carry with it: the navicular, internal cuneiform, 1st metatarsal and hallux. Do you disagree with this?
     
  6. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    I wish I could ask Merton Root that same question. Some of his research was brilliant. But his foot classification system was flawed.
     
  7. scotfoot

    scotfoot Well-Known Member

    Are you saying that the foot types or morphologies described by Root don't exist at all ?
     
  8. I believe that you have renamed a foot posture that was well known in the literature long before you called it “Rothbart foot”, can the first metatarsal dorsiflex without supination?

    I agree that talar torsion may occur during embryonic development as described by Straus 1927 and Bohm 1929. However, based on the data we have from the two studies by McPoil and later Lufler, the best evidence suggests that torsion observed in the talus is unrelated to forefoot position in the skeletally mature human. Any data to the contrary? No.
     
    Last edited: Nov 19, 2021
  9. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Your comment: I believe that you have renamed a foot posture that was well known in the literature long before you called it “Rothbart foot”, can the first metatarsal dorsiflex without supination?

    I understand why you feel I simply renamed a priorly reported foot structure. The confusion is partly due to a misunderstanding in terminology.
    • The term supination refers to a movement.
    • The term supinatus is an embryological term referring to a structural torsion (along the transverse axis) resulting in an invertus (not inversion) of the entire embryological medial column of the foot.
    If you revisit my photo earlier in this discussion, you will see this structural twist in the 1st met and hallux. This can be confusing without a strong background in embryology.

    To summarize: A foot in supination (the first metatarsal that is positionally dorsiflexed) is not the same as a embryological medial column in supinatus (structurally twisted along its' long axis). Lambrinudi MPE is not the same as PMS (RFS).

    You said: I agree that talar torsion may occur during embryonic development as described by Straus 1927 and Bohm 1929. However, based on the data we have from the two studies by McPoil and later Lufler, the best evidence suggests that torsion observed in the talus is unrelated to forefoot position in the skeletally mature human. Any data to the contrary? No.

    Currently, the only contrary data is my research and the embryological plates demonstrating the medial column being modeled by the supinatus of the talar head and neck.

    Posterity will tell who is correct.
     
    Last edited: Nov 19, 2021
  10. Yes Brian I understand the difference between supination, supinated and supinatus. Let me put it another way: can you post pictures of radiographs showing a metatarsus primus elevatus and a metatarsus primus supinates so that may observe that there is no supinatus component in the metatarsus primus elevatus foot and that there are clear differences between the two foot types?

    You keep mentioning embryological plates- where are these published? Regardless you are unable to provide any data which correlates talar torsion with forefoot position in a skeletally mature adult. I can provide data from two papers which say there is no correlation. As a good scientist, I’ll go with the weight of evidence, but always happy to change my mind should the evidence base suggest it is necessary to do so, but that ain’t today.
     
  11. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    You wrote: ".... can you post pictures of radiographs showing a metatarsus primus elevatus and a metatarsus primus supinates so that may observe that there is no supinatus component in the metatarsus primus elevatus foot and that there are clear differences between the two foot types?

    Standard xrays are two dimensional. You need a 3 dimensional xrays to demonstrate the supinatus.

    You commented: " You keep mentioning embryological plates- where are these published? Regardless you are unable to provide any data which correlates talar torsion with forefoot position in a skeletally mature adult. I can provide data from two papers which say there is no correlation. As a good scientist, I’ll go with the weight of evidence, but always happy to change my mind should the evidence base suggest it is necessary to do so, but that ain’t today."

    Again, it is not my intent to change your mind, only to present my research.

    Regarding the embryological plates, I included them in my 2002 paper.
     
  12. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Interpreting PMSv

    PMSv vs Foot Structure.jpg
     
  13. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Measuring PMSv

    Measuring PMSv.jpg
     
  14. 3D notwithstanding, we can take multiple views. So to be clear you don’t have any radiographic evidence, or for that matter any other form of medical imaging that demonstrates that there is no supinatus component within what is termed a metatarsus primus elevatus and that you cannot provide any imaging evidence showing the difference between a metatarsus primus elevatus and a metatarsus primus supinatus? We just gotta take your word for it. Moreover, you have no data which shows a correlation between talar torsion and forefoot position in a skeletally mature human; we just gotta take your word for it and ignore the data from two studies: data which says there is no correlation. I wouldn’t be a very good scientist if I just took your word for it, would I, Brian?
     
  15. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Again, Simon, time will tell if my research is revolutionary or not. And, please clarify, are you asking me if I think you are a good scientist?
     
  16. The day I seek approval from you will be a cold day in hell; don’t think we’ve forgotten your highly distasteful blog following the suicide of Robin Williams in which you suggested that Williams suicide could have been prevented had he sought you out to have treatment for his “Rothbart’s foot”; your academic title of “professor” that you did not hold nor have any justification for it’s continued use by yourself, need I go on? (Rhetoric). No, you sir are the antithesis of the scientist that I should aspire to be and the last person on this planet that I’d seek validation from.
     
    Last edited: Nov 19, 2021
  17. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    There you go again, reverting back to your execrable behavior.
     
  18. scotfoot

    scotfoot Well-Known Member

    No Brian, you threw the first punch and you were on the back foot in the debate .
     
  19. But no defence from you for yours either, Brian.; I guess the truth hurts. Nor any hard evidence for the two central tenets of your so called, self-called “paradigm” other than your personal opinion. Meh, stop making things up as you go along or prove me wrong. I won’t hold my breath. Show me what a good, honest scientist you can be; change my opinion of you…
     
  20. efuller

    efuller MVP

    I did not see where Gerald asked the above question. I made the statement below.

    Brian, you are coining a term that should use physics to explain what it is. Yet, in this thread you were critical of the over complication of biomechanics with the use of the terms force and moments. Brian you have introduced the term gravity drive pronation without a way of understanding what the term means. If you cannot define gravity drive pronation in terms of forces and moments there is no reason for you, or others, to use the concept.​


    You have shown, again, that you unable to define your terms in terms of forces and moments. It is interesting that you twisted the question around so that you could try and fit the answer within your paradigm. I can understand why you said that discussions of forces and moments make your head hurt. It can be painful when existing science does not fit with your paradigm.

    The science of movement analysis has progressed from Inman's work in 1976. Most of what you describe is correlational rather than causational. See Winter's work on movement analysis.
     
  21. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Eric,

    Regarding definition of terms, I understand your point of view, but disagree.

    What surprises me is no one has commented on the gait animations I have presented demonstrating gravity drive in RFS and using ProStims. The movement patterns are consistent with the concept of gravity drive pronation.
     
  22. scotfoot

    scotfoot Well-Known Member

    Brian
    IMO your classification of foot structures is unjustified .
     
  23. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Understood.

    Again, it is not my intent to convince anyone of anything. It is my intent to present my research to the readers in this forum and give them an opportunity to make up their own minds.

    Over 1900 Views and counting!
     
  24. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    RFS vs Plantargrade Foot

    RFS vs Plantargrade Foot.gif

    The above animation demonstrates the 1st met and hallux supinatus associated with talar supinatus.

    Note:
    • Supinatus of the talar neck and head carriers with it the entire embryological medial column of the foot (this includes the 1st met, it does not include the lesser mets).
    • Supinatus is not the same as elevatus. Supinatus is a structural twist around the long axis of the bone. This is easily visualized in the above animation
    If we were dealing simply with an elevated 1st metatarsal, the shape of the proprioceptive signal underneath the 1st metatarsal would be rectangular.

    Because we are dealing with a supinatus deformation (RFS), the proprioceptive signal underneath the 1st met/hallux is shaped like an Isosceles triangle (nadir lateral, apex medial)
     
    Last edited: Nov 20, 2021
  25. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    From the above animated photos, it demonstrates that RFS is not Forefoot Varum renamed.
     
  26. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Forefoot Wedge used to Treat RFS

    Forefoot Wedge.jpg
     
  27. But it’s all bullshit, Bri. Wasted your money on those animations. Hard data, real data… not animations; run along, be a good scientist
     
  28. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Simon,

    All researchers have their critics and you demonstrate that fact perfectly!
     
  29. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    A photo animation demonstrating the link between the unwinding of the talus (black arrow) and the remodeling of the embryological medial column of the foot.

    For simplicity sake, only the talus and 1st metatarsal are depicted.


    Plantargrade-vs-RFS-Photo-with-Bones.gif

    Note

    • Only the 1st metatarsal is in supinatus (twisted inward along its longitudinal axis)
    • Metatarsals 2-5 remain unaffected by the talar supinatus (e.g., rest on the transverse plane)
      • Roots Forefoot Varum describes all 5 metatarsals being inverted relative to the posterior bisection of the heel bone.
    • During the completion of the normal ontogenetic development of the foot, the developing foot continues to unwind (attenuation of supination) resulting in a plantargrade foot.
      • The above animation depicts what is actually occurring around week 12pf.
      • If this torsional development is prematurely ended during this time frame, the neonatal is born with a foot deformation, diagnosed as RFS.
     
  30. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Below demonstrates the development of the foot, where it first appears as a foot pad (Stage 15), to Stage 23 where both the calcaneus and talus are in supinatus

    Cephalad to Supinatus.gif

     
  31. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Below is a recapitulation of the cartilagineous unwinding during the first trimester, calcaneal supinatus to plantargrade

    1st trimester Foot Development.gif

    Frame 1 & 2 - calcaneus and talus in supinatus
    • If the ontogenetic development of the foot prematurely ends during this stage, the baby would be born with a PreClinical Clubfoot Deformity
    Frame 3 - Calcaneus unwinds, talus still in supinatus
    • If the ontogenetic development of the foot prematurely ends during this stage, the baby would would be born with a RFS
    Frame 4 - talus unwinds
    • This completes the ontogenetic development of the foot. The baby is born with a plantargrade foot
     
  32. Just more of the same though really, Brian. No data to support your hypothesis, just made up animations. Non-science.
     
  33. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Hip Drive - directing the motion in the foot
    • Hip Drive Pronation = Normal Pronation
    • Hip Drive Supination = Normal Supination

    Normal Foot Pronation.gif

    At Midstance:
    • Hip Drive reverses the motion in the foot, from pronation to supination
      • The pelvis is externally rotating, the ipsilateral foot changes from pronation to supination
      • The foot motion is being controlled by the transverse plane rotation of the pelvis
    Vs. Abnormal Pronation
    • Gravity Drive continues the pronation
      • The pelvis is externally rotating, the ipsilateral foot pronation continues
      • The foot motion is no longer controlled by the transverse plane rotation of the pelvis
     
  34. efuller

    efuller MVP

    No it demonstrates that you can draw pictures. A foot type causes pronation from neutral position. Is that your paradigm's or is that Root's? Sure seems the same.
     
  35. efuller

    efuller MVP

    So that is what it is about.

    Some people like watching a train wreck.


    If those pictures are the best evidence that Root and your ideas are significantly different, then yes, the readers should be able to make up their own minds.

    If you wanted to convince someone that your ideas were different you would compare Root's ideas to yours. Give Root's definition of foot types and then give yours and explain the differences between them.

    Saying that Root's foot type doesn't exist is a non starter.
     
  36. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    You comment: “So that is what it is about. Some people like watching a train wreck.”

    IMO, that analogy is a little too morbid. I think a more apt one would be: Some people like to learn and be entertained at the same time.

    Regarding your suggestion: “Give Root's definition of foot types and then give yours and explain the differences between them.”

    Today, I believe most Podiatrists understand that Root’s foot classification is flawed (even through it is still being taught at the NY College of Podiatric Medicine). An excellent discussion on this subject was presented by Kevin Kirby, online, in 2009 entitled Are Root Biomechanics Dying

    Also, two excellent papers by R Kidd:
    • 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.
    And a replete discussion transpired on this forum (December 2014) entitled Forefoot Varus Predicts Subtalar Hyperpronation.

    Hence, an indepth discussion, comparing Root’s allegorical foot classification to the embryological foot classification system, IMO, would only belabor the point. But I would be willing to engage in such a discussion in a separate thread, if you agree to participate. I would also request input from several other readers, regarding their interest in such a discussion.

    I would titled that discussion – Why from an embryological point of view, Root’s foot types cannot exist.

    Just a word of caution, such a discussion would be very dry and steeped in Embryology. I foresee that such a comprehensive discussion would be best placed on a embryology forum.
     
    Last edited: Nov 23, 2021
  37. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Here is an animation showing the development and growth of the lower and upper limbs during embryonic development. (presented byLumen Anatomy and Physiology, Modeule 9: The Appendicular Skeleton)
    • at approximately 2.o1 you will see the PreClinical Clubfoot Deformity
    • at approximately 2.02 you will see the RFS
    • at approximately 2.04 you will see the plantargrade foot
     
  38. Brian A. Rothbart

    Brian A. Rothbart Well-Known Member

    Regarding the above video, the dictum: imago (vel hic video valet) mille verba, says it all.

    I believe my embryological foot classification system will be adopted by our profession, but most likely, not for a while. It greatly simplifies one's understanding of the three most common genetic foot abnormalities and provides the rationale on how to treat them.

    This takes me full circle, back to where I started this discussion, Occam's Razor: "plurality should not be posited without necessity".
    • Or, if one were to oppose Root's classification system with mine (as Eric might have suggested), William Ockham would suggest, "when you have two competing theories that make exactly the same predictions, the simpler one is the better."
    The End
     
  39. Two wrong theories don’t make a right one
     
  40. efuller

    efuller MVP

    I agree with you that Root's paradigm is flawed. Your stuff suffers from the same problems. One of them is trying to describe the cause of motion without the use of physics. Another problem, that you and Root share, is that 98% of feet are considered abnormal.


    I don't want to participate in that discussion and I don't see why you would. If the prediction from your paradigm that a Root foot type cannot exist then you have a big problem. If you use the measurements that Root et al describe you can find, in nature, that foot type. When your predictions don't match reality it is time for a new paradigm.

    You can't use Root's types don't exist as an explanation of how your types are different, if your types are the same as his. That is just saying that your's don't exist either. Are afraid to put your definitions next to Root's?
     

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