Welcome to the Podiatry Arena forums

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

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

Should Podiatrists Think More Like Engineers?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Kevin Kirby, Mar 27, 2014.

Thread Status:
Not open for further replies.
  1. No, Dennis. The problem is you make stuff up which isn't true to sell orthoses and advertise these untruths on the internet to make more money.

    Here on Podiatry Arena you make stuff up which isn't true to justify why you can use a fluid-filled plastic bag to treat patients you have never examined or seen walk or run and charge people $399.00.

    You have yet to convince even one of us that your product does what you say it does because:

    1. You seem to think that we don't understand biomechanics of the foot and lower extremity as well as you do.

    2. You haven't read the most recent biomechanics literature on foot and lower extremity biomechanics and foot orthoses and your writings so far on Podiatry Arena demonstrate a poor understanding of the kinetics and kinematics of human gait.

    3. Due to your lack of professional writing skills and your lack of basic biomechanics terminology your descriptions are imprecise, ambiguous and confusing.

    4. You have not a shred of scientific research to support your wild and extraordinary claims for your product.

    5. You simply can't understand that in today's healthcare world which demands evidence based research that the plural of clinical anecdote is not evidence.

    Dennis, I suggest you chill out and say you are sorry to everyone you have already offended. Then, after you have apologized, maybe ask us how you may be able to improve your product for your customers, instead of telling all of us that we don't know as much as you do. You may be surprised at how helpful we may be able to be for you and possibly for your product if you could only deflate your ego down to more tolerable levels, given your lack of any other significant credentials.
     
  2. From Dennis's magazine article:
    "if any segment even partially unlocks or destabilizes, re-supination to a stable-neutral position is questionable. I will refer to this as the optimal position." and:

    "At mid-stance, hydrodynamic pressure loads and self posts the midfoot and forefoot to an equilibrium state of stability concurrent with the subtalar joint optimal position."

    Your repeated use of the definite article and the singular "position" sounds like you are a talking about a single optimal position to me, Dennis.
     
  3. Eric once said: "Pronation isn't a problem, it's what has to stop it that's the problem" He was right. As long as the tissues are functioning within their Zones Of Optimal Stress (ZOOS), then it's no problem. So, yes pain would be a reasonable discriminator in most cases.

    Think about what might happen to the kinematic graph when the subject was walking uphill, downhill, traversing an inclined plane, stepping sideways, stepping backwards, climbing stairs, dancing a tango, jumping a hurdle, hopping, skipping etc.

    Let P = subtalar joint position at midstance, then P= G + E + (GxE) where: G = genotype and E = environment (all non-genetic factors) the equation tells us that P will vary from person to person and from environment to environment, thus you cannot apply a single "biomechanical optimal position" across a population, nor can you assign a single "biomechanical optimal position" to a given individual across multiple environments nor locomotor tasks. You have to consider variation and embrace it, which is what Root and others have failed to do. Moreover, you have to consider the tissues stress levels on an individual basis.
     
  4. fabio.alberzoni

    fabio.alberzoni Active Member

    Dennis, I'm really not confused about my question..may be about the answer. I never heard about your orthotics so I don't want to discuss it. I don't won't to be used for your fight...I mean, you responded to me to provocate Simon. This is not usefull for me and for the blog.


    Simon: Ok, now let me try with an example.
    Patient with valgus knee,intrarotated hip, pronated STJ (assume 5°)....no pain, come to me with her mom having an important HV.
    Now the P(HV)= G(presence of HV in the previous generation and biomechanical problems)+ E(more or less the same of her mother)+ (E+G).
    May be we have a medial STJA and 10° of ankle dorsiflexion...

    I mean...I think should be better to have an orthotic treatment.

    QUESTION: Root initial biomechanics should tell me: invert the heel! now I should have a Jack test or something else to check there is no stress on MP I?...or other structures?

    thanks
     
  5. wdd

    wdd Well-Known Member

    Now your talking - although for all the reasons you have highlighted above I am not too sure that Dennis is the man to take things forward. I feel that Dennis, as a man of his time, has done what he can with the idea and that it now needs a younger person or younger persons to champion the idea.

    However the concept of a pressure activated, fluid containing, 'orthosis' whose therapeutic action is dictated by the predetermined directions and rates of flow of fluid through separate or connected compartments or channels and oneway pressure valves within the 'orthosis' seems to me to offer a lot of scope for this idea and might, depending upon the design of the internal structure, allow it to fit any of the current biomechanics paradigms?

    It might even be possible, for those thinking like engineers, to bring the two (?) current orthotics concepts/technologies together ?


    Bill
     
  6. Bill, I agree. When Dennis first published his article I said something along the lines of the article was weak but the concept of using fluids had potential. However, the insoles in their present iteration was probably not the correct solution. I stand by that contention and agree Dennis isn't the right individual for the task.
     
  7. Fabio, the example you give was the topic of my PhD. I'll reply in full after my clinic today. Suffice to say that this is where modeling of tissue stresses comes into play. You'd do well to read Eric's paper on the windlass mechanism.
     
  8. OK, so if we say that our phenotype is the hallux abductus angle then we can partition the variance as being P= G + E + (GxE).

    First point, E of the daughter is NOT the same as the mothers. When I was writing my thesis I asked Prof. Falconer http://www.amazon.com/Introduction-Quantitative-Genetics-4th-Edition/dp/0582243025 if he thought the shoes worn by females was sufficiently similar to be classed as a "shared-environment"- he laughed at me. You've got to remember that environment here is everything which isn't the genotype, not just things you might think of as being the environment, like shoes.

    Now, you said that there is a positive family history and we know from my PhD and from subsequent studies that there is a genetic component to hallux valgus. However, in the second half of my PhD, when I was building predictive multivariate models, the presence of a positive family history was actually only a very weak predictor within the model (if memory serves it accounted for only about 2% of the variance), so to base the decision of "to treat or not to treat" on positive family history in isolation may not be the best.

    The predictor which accounted for the greatest variance in my model was a static measure of foot pronation (approx 40%), then things like length of the 1st met, age, gender (female increases risk) and 1st ray position (plantarflexed increases risk). Eric's modelling within his windlass paper provides a reasonable explanation as to the pathomechanics for the development of hallux valgus in association with some of these predictors. Given this knowledge, we should be able to build a foot orthosis which MAY lower the risk of hallux valgus development by incorporating features which SHOULD reduce the dorsiflexion stiffness of the hallux. BUT and its a big BUT, we have no studies to demonstrate this.

    So if you have a female patient with a positive family history for hallux valgus, pronated foot, mobile plantarflexed first ray, long 1st met and a high dorsiflexion stiffness of the hallux, it may be helpful to use a foot orthoses designed to reduce the pronation and decrease the dorsiflexion stiffness of the hallux. However, the best available evidence for conservative treatment using foot orthoses in juvenile hallux valgus comes in the form of night splints. http://www.ncbi.nlm.nih.gov/pubmed/1429792 and Macfarlane A, Kilmartin T. Conservative treatment of juvenile hallux valgus -- a seven year prospective study. Br J Pod. 2004;7:101–105.

    See this also: http://ptrehab.ucsf.edu/sites/ptrehab.ucsf.edu/files/documents/O'Neill, Danielle.pdf
     
  9. efuller

    efuller MVP


    Dennis, you may be confusing threads. There are no scans at the beginning of this thread. Do you remember the name of that thread, or are you just bluffing.


    I just read your podiatry today article. Simon was kind to call it weak. There are many paragraphs of gibberish. They are mostly gibberish because there is widespread use of undefined terms that are not standard engineering terms.

    No, I just need to you to refer to the post where you think you explained everything. Just claiming that you explained something does not mean that you did. Either try again or give us the post number.

    Remember the above quote on the supination resistance test. It will be contradicted later in the same post.







    So, how does the increase in fluid raise the TNJ? This is how the supination resistance test applies to fluid orthotic technology. To raise the TNJ, something has to push somewhere to raise the arch. The supination resistance test tells us that some feet will have arches that are harder to raise than others. This is why the same amount of added silicon will not predictably raise the arch. Sure if you add silicon it will feel more like a lump and if you takes some out it will feel less like a lump. That is what you are predicting.


    I have been writing follow up. You've just missed/ignored them.

    Eric
     
  10. fabio.alberzoni

    fabio.alberzoni Active Member

    Wow...very interesting study.
    where can i find eric's paper?

    thanks a lot
     
  11. I've been waiting for Dennis to answer my initial question so that we could move onto this little beauty from Dennis: "Now, the transference of the forward momentum and sagittal force on the foot coupled with the weightbearing and pronatory forces of the midtarsal joint complex against the position and surface of the orthosis at the end of midstance, disengages the metatarsophalangeal joint (MPJ) complex". Ignoring some of the other madness, I'd really like someone to tell me how the metatarsophalangeal joint complex becomes "disengaged"? WTF?

    Yep.
     
  12. Ask Eric, nicely.
     
  13. efuller

    efuller MVP

    The papers compliment each other.

    Fuller, E.A. The Windlass Mechanism Of The Foot: A Mechanical Model To Explain Pathology J Am Podiatr Med Assoc 2000 Jan; 90(1) p 35-46

    Fuller, E.A. Center of pressure and its theoretical relationship to foot pathology.
    J Am Podiatr Med Assoc. 1999 Jun;89(6):278-91
     
  14. I'd also add that your and Kevin's chapter in this book http://www.bipedmed.com/ provides a great discussion of modelling too, certainly shaped the way I work when I first read it, too many years ago.
     
  15. Dennis Kiper

    Dennis Kiper Well-Known Member

    Eric

    So, how does the increase in fluid raise the TNJ? This is how the supination resistance test applies to fluid orthotic technology. To raise the TNJ, something has to push somewhere to raise the arch. The supination resistance test tells us that some feet will have arches that are harder to raise than others. This is why the same amount of added silicon will not predictably raise the arch. Sure if you add silicon it will feel more like a lump and if you takes some out it will feel less like a lump. That is what you are predicting.

    I'm so glad you asked this, this is one of the finest examples of misunderstanding and lack of knowledge about fluid technology you can get. Obviously, others are thinking the same way.

    how does the increase in fluid raise the TNJ?

    The TNJ is the “weakest” and “strongest” point of pronation (watch Kevin say “I made this up”. Since the TNJ has the greatest ROM of pronation of any other joint in the foot (as per the research reference), and fluid moves to the area of least resistance and greatest need (Kevin is going to say I made this up too—he'll be right), the highest forces from the rearfoot, lateral column and forefoot will displace that fluid medially (to the area of least resistance...) and SUPPORT or in the case of more fluid, “RAISE” the TNJ. (let's see if someone asks the right question here)

    This is why the same amount of added silicon will not predictably raise the arch

    wrong again Eric, raising the TNJ hydrodynamically supinates the planes of motion at the tarsus.
    The arch either raises, or at the very least supports the MTJ and limits the ROM of the STJ. (I know this is tough for you guys, such a radical technology to embrace is never easy)--I'm going to leave this answer as is for now, but it is incomplete.

    Sure if you add silicon it will feel more like a lump and if you takes some out it will feel less like a lump

    Eric, you really shouldn't make statements where you don't know the outcome!--If the Rx is correct there's no sensation of a lump (unless you're just standing still for an extended period of time, as I stated earlier).
    If you remove fluid from the Rx, say in a case of “over-correction”--then the fluid more accurately fills the tarsus, meta-tarsus and forefoot and there's not less of a lump—there is no lump.

    BTW--”predicting” is not the correct term in my book, “expecting” is.
     
  16. Dennis Kiper

    Dennis Kiper Well-Known Member

    Bill,

    Bill, I agree. When Dennis first published his article I said something along the lines of the article was weak but the concept of using fluids had potential. However, the insoles in their present iteration was probably not the correct solution. I stand by that contention and agree Dennis isn't the right individual for the task.

    thanks for your comments on some semblance of sanity. Make no mistake about the "iteration" of the fluid technology I use, after 26 years, many other "itiots" have tried.
     
  17. Dennis Kiper

    Dennis Kiper Well-Known Member

    Eric

    I just read your podiatry today article. Simon was kind to call it weak. There are many paragraphs of gibberish. They are mostly gibberish because there is widespread use of undefined terms that are not standard engineering terms.

    If it's “gibberish” to you, you just don't understand it.

    undefined terms that are not standard engineering terms.

    standard engineering terms??? I'm only a podiatrist who tries to “think like” an engineer (can't wait for the flood of response on this).

    Why do you guys always try to be vague?--Be more specific!
     
  18. Dennis Kiper

    Dennis Kiper Well-Known Member

    highest forces from the rearfoot, lateral column and forefoot will displace that fluid medially (to the area of least resistance...

    "highest forces"--Kevin will be very uptight with my "professional writing skills"--
    "wt bearing and pronatory forces"
     
  19. Correction, somebody strap Dennis in.
     
  20. admin

    admin Administrator Staff Member

    This thread has run its course. Its now going back over hold ground and the tone is degenerating....and, besides ... I getting bored with it.
     
  21. admin

    admin Administrator Staff Member

    Here is the full text of the article that started this thread.
     

    Attached Files:

Loading...
Thread Status:
Not open for further replies.

Share This Page