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So, how do we study foot orthoses?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Simon Spooner, Jul 9, 2015.

  1. Members do not see these Ads. Sign Up.
    As many will know, I have argued that there is no such thing as a "placebo", nor "sham" foot orthoses for severel years now, since you cannot introduce anything at the foot-orthosis interface that will not impact on the mechanics at the foot-orthosis interface (since foot orthoses work by modifying the mechanics at the foot-orthosis interface, you cannot make a "sham" foot orthosis). It seems that the research is supporting my opinion now. We have this: http://www.sciencedirect.com/science/article/pii/S155171441500066X , Nester commenting at the Langer biomechanics summer school, in the first image attached, and most recently in the second image attached from the a research group at Calgary presented at the Footwear Biomechanics Symposium 2015.

    Given that by their very nature, custom foot orthoses are unique and given that foot orthoses can only ever exert direct mechanical effect by virtue of the changes they make in terms of the topography at the foot-orthosis interface, the stiffness at the foot-orthosis interface or frictional chararacteristics at the foot-orthosis interface, how should we best study foot orthoses effects?

    Clearly the "gold standard", "double-blinded placebo-controlled trial" cannot be done. Where now?

    Attached Files:

  2. Agreed. We had this discussion with Drs. Karl Landorf and Hylton Menz nine years ago when I criticized the use of a custom molded plastazote orthosis as a "sham device" in the study on plantar fasciitis (Landorf KB, Keenan AM, Herbert RD: Effectiveness of foot orthoses to treat plantar fasciitis. A randomized trial. Arch Intern Med, 166:1305-1310, 2006). I contended that a custom molded plastazote orthosis was not a "sham device" and therefore was not truly a good control to measure against other insole/orthosis/insert conditions.

    Here is what I wrote to Karl Landorf about his study on July 4, 2006:


    Here was one of Hylton's replies to me (July 5, 2006) in the following thread regarding their "sham device" used in the study by Landorf et al.


    Obviously, scientific research has now shown that these "sham devices" may not be as "inert" as the authors of this 2006 study previously thought.
  3. Kevin, you and I and a few others could see the problems with this, (I can still see Landorf's face when I presented FEA analysis just after he'd presented his PHD at PFOLA and I said there could never be a placebo foot orthosis. I didn't present well that day, but I was as right then, as the science is today- no such thing as a sham orthosis- end of story). We've even had other authors, asking questions on Twitter and then deleting the posts, only to use the reply's somewhat out of context in their own blog's, put forward as a defence of a paper in which a "sham" foot orthosis was employed. However, given our current knowledge, how should we design foot orthoses studies? I've opted for single-case designs in the past e.g. http://www.ncbi.nlm.nih.gov/pubmed/16988168 Yet, this is criticised for being a single-case design, which is low on the evidence-base hierachy. So, how do we meet the "needs of science" without "fudging the science" (by pretending that we have invented a "sham" foot orthosis)?
  4. drhunt1

    drhunt1 Well-Known Member

    Well, this topic certainly brings into question several contributors comments to me about my growing pains article, doesn't it? They proclaimed that my study was null and void because I didn't utilize a control group...using a placebo orthotic. Forget the fact that my treatment was basically 100% successful, the entire study, in their opinion, should be dismissed because a placebo orthotic was not used. When I mentioned that much of biomechanical studies are not "as amenable" to evidence based medicine, I was challenged again by an Aussie Pod. Perhaps its time to "wring this one out", if for no other reason than to move forward so Podiatrists worldwide can reclaim our rightful position.
  5. achilles

    achilles Active Member

    Back again from the wilderness, have to agree that there can be no "sham" device as any foot insert will have produce an effect as will any other extrinsic factor, temperature, ground reaction etc...
    The best we can hope for is a baseline from which to compare the effects of a specific device, this obviously may vary and of course would not be a gold standard, but as we are dealing with individuals in individual circumstances in clinical practice, I see little other choice
    Just a thought!!
  6. OK Tony, long time no see. You well? Maybe we can't have a placebo foot orthosis, but we still need a control group in our studies of foot orthoses outcomes. Like the slide said, perhaps the best control is just the subjects regular footwear. I think we should still require a control group in our studies of foot orthoses outcomes, don't you? Better to compare to no intervention as Kilmartin did http://www.boneandjoint.org.uk/high...ield_highwire_article_pdf/0/210.full-text.pdf , than to not compare at all, i.e to just report on a treatment group.
  7. Simon and Tony:

    My thought is that you must have a control in order to best study the mechanical/neurological effects of foot orthoses. The suggestion of just using the patient's shoe without an orthosis is a good control but then the patients in the study would obviously know that they aren't receiving any intervention during their research. Alternatively, I think that possibly a 2-3 mm EVA insole with a minimal medial arch support that doesn't touch the medial arch of the patient may be a good sham orthosis. It would provide a slight amount of cushioning but would provide little to no arch support which should not alter the kinematics of gait and would affect the kinetics of gait minimally. Plus the patients would know that they are receiving some sort of intervention.

    What do others think?
  8. rhs067

    rhs067 Welcome New Poster


    Someone alerted me to use of one of my slides. My presentation materials are never self-contained in that the slide never says everything. Otherwise congress could be just a series of slides without presenters. To think otherwise is quite dangerous practice and a better approach would be to go to the paper itself and draw your own conclusions.

    In this case I use the paper referenced to show the separate and combined effects of choices in orthotic geometry and material on plantar pressure. There are changes in pressure when using a flat piece of material too. I use this as an example/introduction to the fact that it is impossible to put something into a shoe and there be no neuro-mechanical consequences. What those consequences are is an entirely different matter. However, the term sham on the slide is in fact incorrect, it should read ‘placebo’. There is an important difference and plenty of places to gen up on that, as you are all aware.

    In orthoses research the issue of ‘inertness’ and choice of control groups/data is very complex, problematic in fact, and different approaches answer different research questions. Different research designs answer different questions, and depending upon your position as a stakeholder, you will want different questions answering. However, perhaps we can each believe that some questions are more worthwhile than others, but also that another stakeholder will rightfully disagree. I would therefore be wary of too readily criticising researchers for seeking to unpick this complex issue when they are doing so in a systematic way, that meets the highest standards internationally, and moves us all forwards in terms of credible practice and research agenda.

    Best wishes,
    Professor Chris Nester
  9. Maybe instead of naming names the question and discussion should be about is there a better way or could there is a new Gold standard for research

    I have always wondered if a system which included all patients using a inert/sham device 1st , those that improve are recorded and potentially excluded and then the custom device introduced to the group that did not improve ( in whatever system is used ie VAS )

    and then the discussion made around the statistic found.

    Sure it might not be the prettiest system, but it would take a look at individual changes, a certain % will improve due to the sham/inert device and that recorded, others will get both devices and results between the custom and sham/inert device can be discussed , the subjects in the study will not know what device in the one being investigated and therefore would be " blind " it may not be a randomized double blind, but it would address the fact that there is no such thing as inert/sham device.

    I am sure there are holes, but maybe a similar study design might work ?
  10. but by changing the stiffness at the foot interface you can have changes in leg stiffness which will/could ( depending where you sit on the whole leg stiffness discussion ) lead to kinetic and kinematic changes
  11. I think the key is that if we are going to use a "sham" foot orthoses, we need to know what the biomechanical impact that has, not just in terms of plantar pressures, but all potential variables. We then need to be certain that anything that the "sham" devices are doing have no potential relationship with the treatment outcomes for the pathology under investigation. Can we do this? Not without long convoluted studies. i.e. we would need 3D kinematic and kinetic studies, EMG, etc. with the "sham" in-situ, then we need predictive models for the pathology in question which have already examined said 3D kinematics, kinetics and EMG etc. to determine whether the changes induced by the "sham" devices, might be impacting upon the outcomes for that pathology, just so that we can be certain that our "sham" is a "sham". Given what we already know, it'll vary between individuals. Viz. it's a lot simpler to have "no intervention" as a control.

    I kind of like Mike's approach above, which is not without problems of it's own, but is similar to the Williams study in which "non-responders" to a given intervention were examined with a different intevention and the variables examined between intervention groups.

    P.S. Send our love to the person who contacted you with regard to your slide, Chris. If you could ask him not to delete his twitter posts once someone has replied to them in the future, that might be a bonus and overall it should be a help toward a more grown-up and conducive approach toward academic discussion of this important issue.
    The whole purpose of publication is such that our work might be criticised in a systematic way by our peers and the flaws exposed. This includes our methodology, whether our paper is published in an international journal or not, is it not? Regardless of whether you are the editor of the journal of a contributing author; is it not? Rather than "being wary", I should absolutely encourage criticism of research papers, in a "systematic way", regardless of who wrote them. Or, do you believe, as you seem to infer, we should be in awe, or even "wary" of such researchers and believe every word that they might write?
  12. Personally, I am not "wary" of criticising any researchers. Rather, I should encourage everyone else, be they undergraduates or post-doctoral researchers to do the same and to challenge everything they read. Don't be "wary", don't be afraid; critically evaluate. That is, to take a similar critical approach and to not be "frightened off" by the authors when they behave in a threatening manner as you would to anything else; alternatively enjoy the surface and believe everything and anything put in front of you. Me? I'm not "wary" nor frightened off by anyone, regardless of who they think they are. And you.......? Bring it on. "Everything you know is wrong"- The Fly U2 "it's no secret...that a liar won't believe in anyone else" _ https://www.youtube.com/watch?v=5Y1YFH9A3Bw I don't expect a response because "it's no secret that ambition bites the nails of success". Anyway, "every artist is a canibal; every poet is a thief, both kill their inspiration, then sing about their grief, oh love...." "Watch more TV, stay asleep..." -They live: John Carpenter
    They influence our decisions without us knowing it. They numb our senses without us feeling it. They control our lives without us realizing it. THEY LIVE.

    However, clearly the principal reason we should be "wary" is that our opinions will not be responded to here, nor influence this group... If THEY post questions on twtter, do not respond, THEY will delete the question after you have answered. If THEY pubish a proposed methodology for a trial, don't bother to respond, since THEY won't change it anyway.
  13. Petcu Daniel

    Petcu Daniel Active Member

    Let me to add to the question : how should we best study foot orthoses effects in daily practice ?
    Single case experimental design, Model Statistic ( http://www.ncbi.nlm.nih.gov/pubmed/7723655 ),... ?
  14. Daniel:

    I agree. Single case experimental design may be the best way forward to better understand the individuality and specificity of different foot orthosis modifications that are currently used in clinical practice within the worldwide podiatric profession for the treatment of a wide range of mechanically-based foot and lower extremity pathologies. Angela Evans, PhD, did a beautiful single case experimental design study in 2003 on growing pains in children with pronated feet. I believe that Angela may have shown us the way forward for more meaningful foot orthosis research with her excellent research study on growing pains.

  15. Chris:

    Thanks for commenting on this important subject. I thought your presentation on this subject was excellent at Biomechanics Summer School 2015 in Manchester last month. I agree that the question of how one might best decide on what type of foot orthosis and/or foot insole design should be considered to be a "placebo" or a "sham" for scientific research on foot orthoses is an important one and is one that is still being worked out.

    That being said, I also agree with Simon whether those of us who are heavily involved in writing and lecturing on foot orthosis theory, foot orthosis biomechanics and the clinical use of foot orthoses for the treatment of mechanically-related foot and lower extremity disorders should be "wary", as you suggest, of criticizing the foot orthosis research of others. This is especially true when the decisions that individuals doing research on foot orthoses regarding their experimental design and on the way they write up their research findings negatively influences the ability of ethical podiatrists around the world from being able to treat their patients with chronic pain with custom foot orthoses.

    For example, let's say a researcher had a personal bias against podiatrists who are in private practice and also felt that these private practice podiatrists were making more money than they should in private practice, given their qualifications, because they felt the "pieces of plastic" they made for patients as orthoses were overpriced and/or felt that these "pieces of plastic" were so expensive that their use by private practice podiatrists were depleting the finite financial resources allocated for their government's health care expenditures. Now let's say that these same researchers subconsciously or purposefully designed and wrote up their orthosis research findings to minimize the therapeutic effects of custom foot orthoses versus pre-made orthoses, "sham" insoles, or "placebo" insoles so that could proclaim to the scientific research and medical communities that custom foot orthoses were actually no better than pre-made, "sham" or "placebo" insoles. What then are those of us who write and lecture on the intricacies and enormous potential therapeutic benefits of well-designed custom foot orthoses to do when we see such research published? Sit on our hands?!!

    In other words, should we all be "wary" of criticizing scientific researchers since their findings mean much more than what their clinically-oriented podiatric colleagues find in their own practices as to the clinical benefits of custom foot orthoses? No. However, by respectfully pointing out to these researchers the problems with their research and how far their foot orthosis research was from what we actually do in private practice situations with custom foot orthoses, we are, in effect, attempting to introduce more reality and clinical significance to orthosis research, in general, for the benefit of our patients who come to us daily with painful feet and lower extremities. Clinicians need researchers to do meaningful clinical research. Researchers need clinicians to inform them of how meaningful clinical research may best be designed...no communication between researchers and clinicians means less-clinically relevant and more problematic research.

    Therefore, we don't need to be "wary" of commenting on problematic scientific research on foot orthoses simply because we may hurt the feelings of those researchers doing that research. Rather, we simply need to be respectful and earnest in our criticisms of their research methods and conclusions to protect the well-being of our patients and our future patients so that they will still be able to have custom foot orthoses made for them through governmental agencies and insurance companies throughout the world.
  16. Phil Wells

    Phil Wells Active Member

    Great question which I wish there were an easy solution to!
    Personally I like Mikes idea and if a robust single case study protocol could be created, maybe we could all start doing some 'in house' research and sharing the results.
    Maybe create a testing protocol for a specif foot complaint (e.g PTTD) and then follow the protocol.
    I am sure that a group consensus could be agreed on a protocol (Might need to be a few omissions from the 'committee' or we may get diverted by snake oil sales persons)

  17. Dr. Steven King

    Dr. Steven King Well-Known Member


    Anything added to the natural element (barefoot) could create a change-affect.

    If that change-effect is intentional then it would constitute an orthotic if not intentional then it would be a terrain variable.

    Could water be an orthotic?
    Yes if it where allowed to freeze on the floor then you could ice skate over it due the reduction of friction and go really fast! an example of terrain orthoses?

  18. Orthican

    Orthican Active Member

    Has your profession ever considered doing a practice analysis? They are valuable when overal nationwide practices and procedures are to be tabulated and compiled. The information helps to determine not what was taught in the school but what people are actually doing in thier day to day routine for a given issue and are valuable at finding consensus from the whole group.
  19. Orthican

    Orthican Active Member

    Just a thought on subject:

    Might be silly but it struck me as plausible.

    What about having all the groups studied in the same shoes? The placebo group get the same new shoes as the others but with nothing in them and the person is told they are "orthopedic shoes" designed for the problem while the others are given the same shoes but with the orthosis interventions. No need for a "sham" and they are also all in the same shoes so therfore that variable has been removed.

    Too simple?

  20. Petcu Daniel

    Petcu Daniel Active Member

    Could you give an example of what the practice analysis is ?
    I think it could be a valuable document related to practices and procedures but from this point till to evidence there are more steps to be done!
  21. Orthican

    Orthican Active Member

    Well, your question was how do we study foot orthoses effects in daily practice? I feel the first thing that is important is finding out more about what everyone actually does in daily practice. Otherwise what is studied will be different depending on where geogaphically you reside as well as the differences with what each practitioner does for a given problem. If there is no solid consensus on what is done for a given problem as a start then people will be studying the effects with a bit of a shotgun approach. The results will reflect that. With the effect of providing more questions than answers.

    A practice analysis is performed to survey all practitioners and find out just what everyone is doing in daily practice and why and what actual level of success they have with a given design for a given problem. Once that is known then you know where your consensus actually is. Sometimes it is not where you thought it was.

    Once you have consensus then you can hone in more on what types of devices/device modifications/additions/etc. to study for what and why.
  22. Dr. Steven King

    Dr. Steven King Well-Known Member

    Aloha Todd,

    Remember you will be testing on living humans and your study will need to be under an IRB -Institutional Review Board if you want its integrity strengthened and research results to be allowed to be published in a reviewed reputable journal.

    I am not sure telling people you are giving them a treatment solution when you are not would be acceptable. Especially if the treatment "orthotic" in question really works.

    "What about having all the groups studied in the same shoes? The placebo group get the same new shoes as the others but with nothing in them and the person is told they are "orthopedic shoes" designed for the problem while the others are given the same shoes but with the orthosis interventions. No need for a "sham" and they are also all in the same shoes so therfore that variable has been removed."

    The protection of human subjects is important and one I think all schools of medicine should have their graduates complete certificate training before receiving a diploma. Because all of us doctors-practitioners should have continual involvement in research, teaching and the protective care for those we are called to care for.

    Link to NIH

    NIH Online Certification Training

    Under Federal law and in compliance with Siena College’s Federalwide Assurance (FWA), anyone engaged in human subject research is required to complete the appropriate training on the protections of human subjects. To fulfill this federal mandate, the IRB accepts the NIH Office of Extramural Research, Protecting Human Research Participants training modules or CITI Protection of Human Subjects Curriculum.

    The NIH training is free and web-based comprised of seven modules. The entire training takes approximately three hours to complete. The IRB will be unable to approve any IRB project without providing a NIH or CITI computer-printed Certificate of Completion along with the application. This policy applies to the PI(s), Co-PI(s), and faculty supervisors.


    Co-PI SBIR A11-109
  23. Jeff Root

    Jeff Root Well-Known Member

    The reality is that what is done in practice lacks consistency from practitioner to practitioner depending on their education, training, licensing, skills, treatment philosophy, treatment modality, etc., etc., etc. It's hard enough to do a study of prefabricated orthoses where every orthotic is in theory identical, since there is no such thing as a placebo orthotic to compare the "treatment" group to.

    If you attempt to do a study using custom foot orthotics, each device is unique even if you standardize the orthotic prescription specifications when each orthotic is custom made from a model of the patent's own foot anatomy. And in real practice, practitioner's don't necessarily use standardized orthotics since many practitioners tailor their Rx to the individual patient.
  24. Dr. Steven King

    Dr. Steven King Well-Known Member


    Good points Jeff.

    One solution is to not use humans and obtain the ground shoe-orthotic contact data from using mechanical testing devices. We are trying to get the army to use these mechanical testing devices for bench top data acquisition on the new advanced carbon fiber and Kevlar combat boots.



    Another thing to consider is to test physical characteristics of the orthotic.

    Say you design a puncture resistant orthotic that can withstand up to 800 pounds of puncture force when tested with ASTM standards. Then when the next time you have a patient with a puncture wound you can provide them with the proper treatment and future protections for their specific body weight and work environment.

    Say you design a full length orthotic with a variable modulus of elasticity and you want to give it to a patient with hallux limitus or a stress fracture. ASTM Flex testing the footwear-orthotic system would be important to match the flex characteristics of the treatment device with the body mass and activity level of the patient. How much do you want the toe to bend or not bend? The answer is in megapascals.

    Not everything about our footwear and gait systems has to deal with position the sub talar joint axis there are many other important attributes and needs for our treatments.

  25. efuller

    efuller MVP

    I've been thinking about trying different modifications of the same customized cast. You give a patient an orthotic with and without a medial heel skive. Or with and without an intrinsic forefoot valgus post.

    The outcome measure may still have to be patient satisfaction/preference. Although gait speed might be an interesting variable. Or perhaps ankle joint power. Looking at kinetics and kinematics will probably be really difficult because we are dealing with the human brain in terms of kinetic output. (The CNS controls the kinetic output).

    As Mert Root pointed out in his writings: feet are different. You shouldn't expect the same treatment to work for all feet. This is another problem with Orthotic effectiveness studies. One orthotic variable that will be helpful for one foot, may not be helpful for another foot. So, to do a good orthotic study you need to have good measures that can differentiate one foot from another. Ideally, these measures will be shown to at least correlate with specific pathology.


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