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Challenging MASS

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Simon Spooner, Nov 27, 2008.

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  1. Members do not see these Ads. Sign Up.
    As a spin off from the challenging SALRE thread, I thought it might bring balance to subject this other theory to similar debate.

    Since Ed is in the mood for talking and as I never did get an answer to these questions regarding this article, perhaps he could be so kind as to answer these now:
    The Short-term Effectiveness of Full-Contact Custom-made Foot Orthoses and Prefabricated Shoe Inserts on Lower-Extremity Musculoskeletal Pain
    A Randomized Clinical Trial
    Leslie C. Trotter and Michael Raymond Pierrynowski
    Journal of the American Podiatric Medical Association; Volume 98 Number 5 357-363 2008

    What happened to the other two?

    ???


    So why don't mass produced orthoses work if a patient is given a flat 4mm foam insole before hand?


    Any thoughts Ed???
     
    Last edited by a moderator: Nov 27, 2008
  2. admin

    admin Administrator Staff Member

    FYI:

    MASS = maximum arch subtalar stabilization = weightbearing casting method proposed by Ed Glaser of Sole Support

     
    Last edited: Sep 22, 2016
  3. Steve The Footman

    Steve The Footman Active Member

    "If one looks at the various strategies currently used for correcting the foot with orthotics though...there are really only two types"Quote from Video

    In which universe/dimension is orthotic therapy divided into MASS orthotics and Root orthotics? Not many podiatrists I know using Root theory to prescribe their orthotics and no one using MASS that I know of. Where does that leave everyone else?

    Since when did Root orthotics have no arch? You would expect more arch in a non-weightbearing casting method than a weightbearing one anyway. That is why plaster is added to the MLA on the positive. Makes me wonder if Ed even understands Root theory!

    If the shell collapses anyway with a MASS orthotic then what is the difference between the end stage in a "flat" Root Orthotic and a MASS orthotic? How much pressure is required to completely flatten a flexible shell?

    I really love this quote from another thread: "It is actually the shape of the superior surface of the orthosis and the resistance of the orthosis to deformation inside of the shoe which determine how functional the orthosis is." Dr. Michael Burns, former Chairman of the Department of Orthopedics at the Pennsylvania College of Podiatric Medicine. (in Precision Intricast Newsletter March 1990.)

    I find it hard to accept that the huge variability you find between patients should not be reflected in your prescription and casting methods. How can any one casting/capture technique or any one type of device be optimum for even a majority of patients?
     
  4. DaVinci

    DaVinci Well-Known Member

    Its a well know debating/argumentative technique that has a latin name, that I can not recall. You characterize what you are arguing against as something that its not, then argue against that characterization. Sound familiar?
     
  5. Craig Payne

    Craig Payne Moderator

    Articles:
    6
    I do not know the latin name, but sound like you are talking about the straw man argument:
    From Wikipedia
     
  6. Griff

    Griff Moderator

    Simon,

    I've only scanned the article but in the results section it states that 2 participants withdrew before the week 2 and 6 visits due to scheduling conflicts. I'm as confused as you as to why they were included in the abstract.
     
  7. I got one!

    Is it misleading to refer to this study in context of other studies comparing customs to pre fabs when they used things like AOLs and shaped devices and this study used a 4mm bit of foam?

    Thats like comparing a taylor made suit to an off the peg... when the off the peg is shorts and a tee shirt!

    So this study set out to prove that MASS was better than a bit of flat sponge such as might be purchased for 99p in any brance of poundstretcher.

    Bit of a "going for bronze" feel to that IMO.

    I think Dr trotter was right on the money here and full credit to her for not sweeping this under the carpet. So if beleif in the mass insoles is lost, they no longer work any better than a flat bit of sponge. Which suggests what as the mode of action for the Mass insoles?

    Regards
    Robert
     
  8. EdGlaser

    EdGlaser Active Member

    My first thoughts are: Are we using the same ground rules here as in the SALRE thread? If not, I will not waste my time. I don't need to explain my personal life to anyone. Contrary to Dr. Kirby's supposition, what I wear for Halloween has nothing to do with biomechanics. He seems to be having a hard time with these ground rules already in "Challenging SALRE".

    These are excellent questions for Leslie Trotter and Mike Pierrynowski. I do not have to defend their research because I do NOT influence the research at all, other than provide the Sole Support Orthoses, funding and ask that our orthosis be included within the study. There are precious few researchers looking at foot biomechanics. I am glad that we are allowed to participate in these studies.

    I believe that when that thread was put on the arena, Leslie was more than willing to defend her paper, but the personal attacks challenging her integrity came so fast and furious that she did not want to waste her time on non-educational blabber. Of all of the people I have met in my lifetime.....Leslie Trotter and Mike Pierrynowski are among those with the most unimpeachable integrity. Attacking their integrity is like accusing the Pope of fathering an illegitimate child; the later is more likely.

    BTW, that thread has mysteriously vanished......wonder why? I saved a copy of the last page. I believe Leslie was so put off by the treatment that she recieved, that she emailed Craig asking to be removed from the arena. I doubt that she will return.

    So, you don't think the results were as flattering to my product as I might like. You are correct. I congratulate Leslie on doing totally unbiased research. My funding has been well spent. Funny, if the results favor MASS theory you simply call it BIAS.....if the results show problems with our technology you give it credibility. Simon, I believe that BIAS is something that you yourself suffer from.

    It seems that one of your perennial arguments with all research is the power. You viscously criticized the GSU research RCT because it was "under powered". I believe it had 17 subjects although the orthoses they tested us against were the best posted Rootian orthoses they had ever tested, the differences measured were enormous and the variation was minuscule (p=.006). Now you conveniently seem to agree with the results of the lower powered half of the study....a bit biased, don't you think? If you do standard power calculations, you will readily see that the half of the study with 27 had a more than acceptable power and the half with 17 was grossly underpowered. This is of no fault of Leslie Trotter or Mike P. I take full responsibility. We had an executive at the lab who was not familiar with research and delayed shipping of the research pairs because she did not know how to credit them in our accounting system at the time. Frankly, I would not have known either..... We have since worked all that out with our new software (we use Netsuite) and future research projects will not be underpowered.

    Thanks,
    Ed
     
  9. EdGlaser

    EdGlaser Active Member

    Robert,
    Again, the choice of prefab was Dr. Trotter and Dr. Pierrynowski's. Why they chose that one is not mine to defend. On one hand you want me to structure and control the research, and on the other, if I do exactly that it will be biased.
    Ed
     
  10. Ian Linane

    Ian Linane Well-Known Member

    Hi

    No offense is meant to either groups but is it possible that both outlooks are so biased by past encounters that have failed, through decent into personal/academic adequacies or inadequacies, that no further possible discussion can occur - without close moderation of posts by an independent person.

    Ian
     
  11. David Smith

    David Smith Well-Known Member

    Ed

    Personally I have lost patience with your retoric. Despite trying to enter into reasonable discussion and in the past asking relevant question after taking time to read and digest all your writings here and on your web site, you rarely take the time to answer and if you do you skate around the answer with waffle about irrelevant issues and muddy the water by saying I .we are biased and are ridiculing you. You aleways manage to back slide your responsibilities onto your research and engineering staff and never make any attempt to answer any engineering based question with an answer that one might expect from a person that "studied mechanical engineering at SUNY Stonybrook".

    On top of that you think that maths and modeling are a waste of time while at the same time buffing the cherry of your 3D animator who produces excellent models to validate your theories. We never see any models or the theory, maths and axioms behind them just like we never see any credible research that explains how MASS type orthoses could work. You continue to use flannel, flim flam and humbug to bamboozle those who cannot see thru the illusionism and then accuse those who can of bias and unfairness in their critique. Strangely I had the same experience with DrSha who tends use the same argumentitive techniques as you.

    Simon asked you a simple question and yet you still managed to skirt around the answer. A simple answer like I don't know might be more honest however, for some who has "studied mechanical engineering at SUNY Stonybrook" and has a doctorate you show poor judgement in the type of research you choose to endorse by publishing it on your website. Simon's question aside the research you publish is just not experimentation to the standards expected by those with professional and research based qualifications.

    Experiment 1)
    The Effect of 2 Different Custom-Molded Corrective Orthotics on Plantar Pressure

    Conclusion:
    The SOLE orthotic appeared to be more effective in attaining the goals of
    custom-molded-orthotic intervention.

    But what that goal is and why those goals are relevant to foot function is not clearly stated .

    Standing on a brick relieves pressure on the metatarsal heads therefore this proves that PAL custom orthoses is less effective than a brick at attaining the goals of custom moulded orthostic intervention.

    Experiment 2)
    The Effect of 6 Weeks of Custom-molded Foot Orthosis Intervention on Postural Stability in Participants With >/=7 Degrees of Forefoot Varus.

    Conclusion
    The current study supports the hypothesis that an increased degree of FV may significantly decrease singlel imb stance PS.

    Even tho that was not the original research question???

    Which was
    The Effect of 6 Weeks of Custom-molded Foot Orthosis Intervention on Postural Stability in Participants With >/=7 Degrees of Forefoot Varus.

    What it does show is that +FO is about the same as -FO after 6 weeks. But we are not very clear on this because we didn't filter enough variables to make any reliable conclusion but we have put in lots of random and arbitary abbreviations in the report so perhaps no one will understand it enough to notice.

    Experiment 3)
    The Short-term Effectiveness of Full-Contact Custom-made Foot Orthoses and Prefabricated Shoe Inserts on Lower-Extremity Musculoskeletal Pain

    This is so full of holes, some of which have already been outlined by Simon and Robert, it could win gold at a most holey Swiss chees competition. The comparison of swiss chees and sole supports being about as relevant and useful as the comparison made in this study. " I can't believe it's not butter" oh no its not its sole supports darn! You just can't tell with a blind fold you know, eh! no you can't, YOU CAN'T. Oh! ok you can then, nice try tho eh?:eek:

    Conclusion
    Conclusion: Full-contact custom-made foot orthoses provide symptomatic relief after 3 weeks of use for patients with lower-extremity musculoskeletal pain if they are prescribed as the initial treatment. (J Am Podiatr Med Assoc 98(5): 357-363, 2008) (as long as they were hypnotised and the suggestion made that sole supports REALLY work, yes they REALLY work. Doh! your suggestability has been compromised by using a simmilar -ish, no its is really, orthosis)

    How it made it into JAPMA beats me??

    Reasearch paper
    Variability of Neutral position casting

    Look here's a limitation of their system so therefore mine must be better and the only one that is correct??

    Publication article By Ed
    Theory, Practice combine for custom orthoses
    Quote
    "The security provided by a long-held belief system, even when poorly founded, is a strong impediment to progress. General acceptance of a practice becomes the proof of its validity, though it lacks all other merit."1 This is the exact situation we find ourselves in today with regard to custom foot orthoses as a biomechanical intervention. The vast majority of practitioners now use a model and method for orthotic therapy that has not undergone serious critical analysis or revision for almost 30 years. "

    Because most people believe in it and have used it for many years (apparently without regard for the fact that apparently according to Ed, it doesn't work but never thought of looking for some other system that did until Ed came along) this proves it must be wrong.

    Smoke and mirrors Ed, as usual, smoke and mirrors.

    Published article by ED
    Focus On Function In Custom Foot Orthotics

    Despite the fact that there are lots of diagrams with big red arrows pointing to a high medial arch and claims of calibrated materials there are no values, figures, validating models, maths, physics or logical reasoning to back up any of this.
    Its all just based on Ed's opinion without even the merest concession to any of the above conventions normaly associated with the propigation of a new theoretical model.

    Ed You could have a good product but we will never know because you are to arrogant to bother with the proof that most intelligent souls require to allow them to change their current thinking.

    Got to go boxing now, see ya tommorrow

    Dave

    NB
    Is this the reasoning of a man (Ed G) with Guiness bottle shoulders and doing the Maltese breast stoke?
     
  12. Ed
    Hmmm. Seemed a very reasonable question to provoke such a defensive response ed. Lets say that Yes we are discussing purely the science and not the individuals behind it. Now i would love to hear your answer to Simon's question!


    No. But you are claiming these articles as evidence backing your product. You cannot in on breath say "behold, the evidence supports my view" and then when that evidence is challenged spread your hands with a sorrowful expression and say "well i did'nt write it!

    If you will not defend these papers you should cease from claiming them as evidence.

    I have no problem with you structuring and controling research! If it is well designed and carried out it would help your case. Indeed that is what we have all been waiting for you to do! Carry out the Study in question with a randomised double blinded protocol and compare your product to a standard root device or even an OTC device like interpods or AOLs and we would really have something to discuss!

    So which is it? Do you suggest that this research supports the product you are trying to sell or do you conceed that it proves nothing more than that your insoles sometimes work better than a 4mm piece of foam (although not if a piece of sponge has been used first). You can't have it both ways.

    Regards
    Robert
     
  13. EdGlaser

    EdGlaser Active Member

    Answering Steve's Good Questions!

     
  14. Ed

    I understand you are busy. Whatever time you can give us is most appreciated!

    For myself i would still really like your view the first question posed by the OP.

    Robert.

    PS - There are more than a few points in your last posts i would take issue with, but i don't want to drive the thread on a further tangent from the OP!
     
  15. Steve The Footman

    Steve The Footman Active Member

    Re: Answering Steve's Good Questions!

    Hi Ed,

    Looking back on my previous thread I think I may have been a bit harsh. Sorry if you took any offence but luckily you appear to have a thick skin. However I still have problems with some of your ideas:

    I understand that it is a good idea to dumb things down for people not conversant with podiatric jargon. My problem is using a premise that the options are just Root theory that is old and disproved or MASS theory. While MASS is new it is unproved as previous comments about the research have highlighted. While you feel from your experience that Root theory is still transcendent I do not feel that is the case at least in Australia. However without any research to prove it both of us are relying on our own anecdotal evidence which is really no evidence at all.

    It is this type of exaggerated self promotion that fails to win supporters from podiatry arena members. I have not seen a revolution occurring so far and certainly on this messageboard there seem to be more detractors than supporters. If a revolution had occurred then you would expect more people to be taken up with the idea.

    Are we not exchanging the old frontal plane seesaw for a new sagittal plane one? I think that a long break in period is a function of inappropriate prescription rather than a necessary phase of adaptation.

    This is a good point as it will give you earlier proprioceptive feedback. The orthotic would also act more like a spring and decelerate the force more efficiently. This is perhaps a good argument against hard rigid shells that do not deform or even orthotics that rely on arch fill rather than stiffness. However I am not convinced that we can 'clinically' model the function of individual feet, within different shoes, during different activities, to the point of enough accuracy to be valid.

    I am not convinced that many feet can make a postural change to an ideal foot function. Sometimes the best we can do is accommodate someone's degenerative joints, muscular dysfunction and genetic heritage. This may exist in the guise of symptom relief and this may still be a rewarding and successful outcome for some patients. With each patient the practitioner may need to use different theories like SALRE, Windlass, High Gear/Low Gear or other theories to make the significant change in function.

    I think MASS theory has appeal due to its simplicity. It seems logical to use an easily replicated position for casting each patient. It certainly would be easier and more consistent for practitioners than using Roots neutral calculations. What I am not convinced about is whether it is any better or less arbitrary than the Root method. Just because it is simple and logical does not mean it is valid or relevant.

    Thanks

    Steve
     
  16. Elegantly put :drinks. This is the availability heuristic for those with an interest in cognitive psychology.

    mmmmmmmm.....

    Nope. can't do it. Can't let that one slide!

    Ed you consistantly refer to mass as
    . This is the fundamental tennant that your arguments hinge upon. Other orthotics may not hold the foot to this posture and therefore are dismissed as unsupportive pancakes. You seem, in your comparison of orthotic arch heights, to presuppose that highest is best.

    What makes you beleive that the MASS position is "best", "most functional" or "optimal" any more than a MAPS (maximum PRONATION) would be (i'm not saying it is before everyone jumps on me) . I would be interested in Either deductive reasoning or Inductive evidence for this.

    However if you only have time to answer one question i would rather hear you answer the OP!

    Regards
    Robert
     
  17. The other thing that occurs to me here: this data suggests that if there is a four week period between casting and fitting of the mass devices they will not work to reduce musculoskeletal pain, the 4 mm flat foam being at best a sham device. So what is the time period likely to be from casting a patient in the UK or elsewhere in world, shipping the foam impression box to Ed's lab in the USA, having the devices manufactured and shipped back to the UK and then getting the patient in for dispensation? Greater or less than 4 weeks? The study used a 4 week period and found that the mass devices did not work after wearing the sham insoles for 4 weeks previously, but we do not know what the actual time period was, it may well be less than 4 weeks.
     
  18. Lawrence Bevan

    Lawrence Bevan Active Member

    Am I missing something.

    "MASS" is a casting technique. How is it a "theory"? Is it revolutionary? I think Mert Root and co-workers certainly made many references to foot morphology and reducing deformity with their methods eg forefoot supinatus . To my mind, cutting to the chase, the MASS position is a casting technique that attempts to speed up the reduction of a supinatus.

    Orthotics made to this shape, still apply moments about joint axes, still are subject to Newtons Laws. They in effect still will increase load on some structures and decrease load on others, this may be therapeutic or not. This is still in line with the principles behind the "tissue stress" approach.

    Some patients will be tolerant of the shape produced some not. Many of those who do not will be explainable by the concept of a STJ axis that is medially displaced.

    And finally, since when was it news that labs over fill medial arches and this lessens the effect of an orthotic? Simply tell your lab not to or you will send the device back and not pay.
     
  19. David Smith

    David Smith Well-Known Member

    Excelleeeeent:boxing:

    Dave
     
  20. pnunan

    pnunan Member

    I still have problem with the MASS theory of casting. Seen it done a couple of times and notice that all it involves is shoving the foot in to foam. Also Dr. Glaser acts as if plantarflexing the 1st ray is something new. Root had the medial edge lateral to the 1st ray and Dannanberg has done his studies with the whole 1st ray theory. How is this new? Further, most of Ed's research staff are chiropractors. Have seen several patients who have been to the chiropractor had the MASS orthotics made and hate them. Some of them really didn't need a custom made orthotic in the first place. Again the whole idea of the arch being the key to the control of the foot is the same theory the developers of FootMaxx threw around a few years ago.
     

  21. I assume this is Pat Nunan? If it is, or even if it isn't, welcome to Podiatry Arena, Pat. Looking forward to seeing more excellent posts from you on Podiatry Arena in the future. Good to have you on board!
     
  22. pnunan

    pnunan Member

    Yes, Kevin it is me. Thanks for the welcoming statements. Look forward to the site as well.

    Pat
     
  23. David Wedemeyer

    David Wedemeyer Well-Known Member


    Pat :good:

    This is the problem with allowing the uneducated, untrained and non-critical/objective providers to sell turnkey orthoses systems they learn about in weekend seminars or from a DVD. Enabling them to be set loose to dispense these expensive little marvels under the marketing guise of "postural control" or "spinal/pelvis stabilizers" as medically necessary by virtue of some illusory standard or as preventive devices is precisely why reimbursement of orthoses continues to decline.

    It is not the fallibility of orthoses we provide that have tarnished their professional equity; it is the unending propagation of designs in avarice marketed to the masses (and based in pseudo-science) that have resulted in the predicament that we find ourselves in with insurers and the marketplace.
     
  24. pnunan

    pnunan Member

    Thanks for the comments David. Whether one is a chiropractor, podiatrist, physical therapist or biomechanists, true research needs to be done. A study supported by one lab, using their orthotics are not an unbiased study. My problem with the MASS theory is that it is not new. It is piece meal of other theories and yet put behind fancy marketing. I am sure there are plenty of patients who do well with the orthotics. The late Richard Schuster once said that you could put tissue paper in a certain percentage of the population and they would claim they would improve. With evidence based medicine coming down the pike, we better clean up our acts.

    Pat Nunan
     
  25. David Wedemeyer

    David Wedemeyer Well-Known Member

    Pat,

    Your assessment of the SS system is spot-on. MASS and the resulting product are nothing new and nothing extraordinary or ground breaking. This design appears too similar to the Whitman and Roberts type orthoses favored at the turn of the century but utilizing a flexible shell.

    I have found that most of the research out there shows that custom orthoses are in fact reliable and efficacious for a variety of lower extremity disorders. Certainly we experience these results in our daily practice and we all should make some contribution to the reporting of these efforts to validate this evidence. The problem seems to be congruency as to the methodology employed. Perhaps evidence based care will shift the focus to more standardization and better outcomes for our patients.

    Ed's fanatical denunciation of Root theory, STJ neutral, pop casting and especially their focus on pronation as the etiology of all foot dysfunction are all marketing sleight-of-hand to blur the myriad possible pathologies our patients experience and fit them into a turnkey approach that is easily regurgitated by the dilettante clinician.

    Smoke and mirrors :wacko:
     
  26. joejared

    joejared Active Member

    If by Root theory, you're refering to Merton Root, all of the labs I work with do. Personally, and with only 13 years of experience in this field, I never heard of MASS, but that alone wouldn't make it wrong. I'm not a fan of supinating or pronating a patient's foot during casting, but there does seem to be many methods out there for casting of patients. The generally accepted best method of casting, however, is prone non-weight bearing in the neutral position.

    As to your second comment above, knowing the patients activities is probably one of the most important pieces of information in the preparation of an orthotic. For the orthotics I wear, I designed a code that would follow the mid-tarsal joints such that weight distribution is even, because I am often found standing in front of a milling machine waiting for a part to be done, mostly standing, not walking around, at least not in full gait. These same orthotics would not be nearly as useful in a normal gait because I would also need to allow for more mobility in the midtarsal joints to shift in a normal gait, but are quite comfortable for my LAZY work habits. One had to appreciate the politically correct term in the video but really, they meant lazy. :D
     
  27. Before i post this post i'd like to take this oppertunity to ask

    Lest i distract from the question of the day. This is the one we're all waiting on.

    That said, let me say this.

    I've been mulling this topic and i have a confession to make.

    I may have been a bit harsh. I sometimes make orthotics Ed's way :eek:

    Let me explain. My method for manufacture is as varied as the patients who come in. I don't have one technique which i apply to all, it depends entirely on the pathology. I use many different materials and techniques.

    However the material i used most, in probably around 50% of patients, used to be hi density EVA (now trying therrox which looks rather better). Hi density EVA will deform under load to the point where the inferior surface of the device contacts the shank of the shoe. At this point it becomes a shank dependant device with the ending arch height dependant on the differrence in thickness between the medial and lateral parts of the device PLUS the amount of support already present in the shoe. So in essence it is shank INdependant for the first part of load and then shank dependant from that point.

    Presuming the orthotic is there to controll pathological pronation i tend to cast the foot in the position i want to START adding extra supination moments to the foot and use a thickness of EVA / other material based on the point at which i want the orthotic to STOP deforming and provide an immovable barrier to further nav drop. I modify the prescription based on any peculiarities of the foot (kirby skives, deep heel cups, wedges, high medial flanges, 1st ray cutouts etc) to offer supination moments from places other than the arch if i deem it necessary or more efficient.

    I suppose this method could be loosely said to be based on Kevins ZOOS. I'm trying to keep the range of motion of the foot within the ZOOS AND provide additional supination moments to the foot within the ZOOS.

    So in a sense i am with Ed on one detail. I like the concept of meeting the foot at a certain point and providing graduated (although not calibrated) resistance up to another point. As a rule i would do this rather than use a rigid device at the point i want pronation to stop.

    I like to think of orthotics as replacing incompetant physiological structures. A bony end range and / or ligaments limit movement. If this range is too high i use a device which provides a hard end point before the joint reaches ITS end point. Muscles provide graduated resistance up to that end point depending on function. If the muscualature is comprimised i try to provide a device which also provides graduated resistance.

    To to this i need the device to contact the foot and start to function before the foot has reached the point i want it to stop at. That point is sometimes below neutral, sometimes neutral, and sometimes, rarely, ABOVE neutral.:eek:

    It may even, in certain circumstances, with a following wind, and in certain lighting conditions, look a lot like the MASS position. Occasionally.

    So there. You can string me up alongside Ed when the revolution comes.

    Regards
    Robert
     
  28. Who says?
     
  29. Angry mob :- "WE FOUND A HERETIC, MAY WE BURN HIM"

    Bedevere :- "How do you know he is a heretic"

    Angry mob :- "HE QUESTIONED NEUTRAL SUSPENSION CASTING"

    Sorry. Could'nt resist it.

    Its a fair point. STJN is probably the position which the majority cast in, however it has never been shown, inductivly or deductivly to be "best". Nor, come to that, has MASS or any other position.

    The Sun has the highest circulation of any newspaper in Britain. Does'nt make it the best! Its just easy to understand and has bare naked ladies in it (like Rootian theory except for the Boobs).

    One of my bugbears is when podiatrists, on being faced with an orthotic which has not had the desired effect, continue to pile up wedging on the medial side and call it "increased correction". Worse is when they tell the patient to come back to me for "increased correction".:mad: Correction implies a "correct" position! If the orthotic (for eg) is for a compressive medial knee pathology it may be that increasing this "correction" would move the foot AWAY from a position which might atenuate the pathology!

    Several times Ed has asked what position other people cast in. Considering the huge variety of pathology that we are presented with, the variety of morphology and function and the variation in manufacture techniques i'm not sure there is a position which is right for everyone! Would you cast someone with a 35 degree fixed supinatus in neutral?

    Kind regards
    Robert
     
  30. Griff

    Griff Moderator

    I'm with Simon and Robert on this one. Despite it being likely to be the way the majority practice most of the time there is no evidence/research that it is either correct nor that it is the best. However I seem to remember reading a thread on here before regarding this and certain methods were shown to be more repeatable (I think it was methods which used a plane of reference such as the ground)
     
  31. Isn't this an oxymoron?
     
  32. Actually, to beat ed to it, the method which has been tested as most repeatable most often is MASS. I suspect fully WB would be even better although i don't know of any studies which have looked at this.

    It kind of makes sense. Foam uses the ground as a reference plane which removes the element of error intrinsic to bisecting the calc. Mass means you are measuring against a fixed joint position, where as Semi WB foam neutral includes the potential error in finding a position in mid range of the joint. I suspect its easier to teach someone to find MASS than neutral.

    However whilst an unrepeatable position cannot be hitting the desired position all of the time, a repeatable position could be hitting the desired position all of the time... or none of the time! If MASS IS the "optimal" for everybody then this is great and good. If its not then you have a technique which gives a bad cast every single time!

    Regards
    Robert
     
  33. Ultimately it is the mechanical properties of the orthosis that is key, not how the negative cast was taken. Negative casts effect neither the kinetics nor kinematics of the foot and lower limb during dynamic function, orthoses do. Anything that's "achieved" in a negative cast can be undone in the positive preparation and orthosis design. Conversely, anything that's "not achieved" in the negative cast can be done in the positive preparation and orthosis design. Just depends where within the manufacturing process you want to put the work in and what you are ultimately trying to achieve.
     
  34. StuCurrie

    StuCurrie Active Member

    Hello Robert and Simon,

    I thought I would jump on here and try to chip in to the discussion of this article. Your question is a good one, and although I do not post here often I am interested in this discussion as it relates to the results of this study. As I think you are aware, I work for Sole Supports (disclaimer) so although I realize you might find my responses necessarily biased to some degree, I think we all have our biases and I hope that it does not preclude you from giving me the benefit of the doubt with regards to my comments and integrity.

    I should probably state first that I was in no way associated with the selection, data collection or write up of this investigation. I only say that because I want to be clear that I do not pretend to have all of the answers here, only that I might provide some insight as I do enjoy the privilege of speaking to and collaborating with the researchers who did complete this work from time to time.

    In response to your question: First and foremost, you are correct in noting that the participants in the prefab-custom group did not note any significantly lower pain scores compared to the second baseline (week 6). This is a fact of the data collection and results. What I think you are asking for are thoughts related to why this might have occurred, in the context of the current debate.

    Some thoughts and possibilities:

    1) One noteworthy result (as you have stated) is that after switching to the custom orthotic, the prefab-custom group did not demonstrate significantly lower pain scores when compared to the effect of the prefab.

    2) This same group did however demonstrate lower pain scores at weeks 9 and 10 (after wearing the custom orthotics for 3 and 4 weeks) as compared to their initial baseline. Can the decrease in pain scores be attributed to the custom only? No, because of the crossover design, but it is interesting nonetheless.

    3) One possibility is that we are seeing evidence of a time dependant accommodation to the device. How does the accommodation to this device (or any device for that matter) factor in? How long does the device have to be worn before detectable results are seen? Interesting question. From the graphs in the study there is evidence of a trend towards lower pain scores after wearing the custom over 4 weeks. This correlates with data from other studies and is something we are learning from and considering going forward.

    4) What is also of interest to me are the results from this study showing that when the custom was removed, the pain scores increased. To my knowledge, this is the first study of its kind to show a result like this.

    I hope this starts to address some of your questions. I also note that there are other threads with references to this article http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=141&page=2 so I hope this is the place for this discussion.

    Respectfully,
    Stu
     
  35. David Smith

    David Smith Well-Known Member

    Robert

    Despite wanting to burn you as a witch you make some interesting comments.
    (Very Interesting but stupid - Unteroffizzer take zis dumkoff out an shoot him)
    No really, when you describe your method of graduated attenuation this makes sense and it is the sort of definition that MASS produced orthoses are short on.

    This is how I would explain your foam model.

    Layers of foam with varying stiffness coefficients can indeed work as a graduated resistance to the motion of interest. This results in increasing stiffness coefficient as the material composite / laminate is compressed or deflected. This is due to first the individual stiffness coefficients and second to the accumalative coefficient effect of compressing all the foams together as force is applied.

    The highly malleable nature of foam allows it also to have a morphology that approximates the plantar surface at all times. These properties are not found in plastics since, unlike foam, the ratio of coefficient of compression stiffness to the coefficient of deflection stiffness is much higher in plastic.

    I cannot imagine how a plastic shell under normal stresses, can have a variable coefficient of stiffness unless it has some visco elastic properties. Some plastics do have this but usually only in tension, polythene is a good example. The material is also not at all malleable in the range of compression forces and temperatures in the enviroment of the shoe.

    The energy curve of foam, especially structures that are laminated with a variable stiffness coefficient, will have a high component of loss and hysterisis in the time scales that we are considering. The opposite is true for most plastics especially those used for an orthosis shell. The force time curve (with increasing load) of foam would be exponential in nature whereas plastic would be linear. Therefore the force to deflection curve (with increasing load) of the plastic would be linear and the foam would be a negative exponential in shape.

    This means that potentially the plastic would exert a lot of force to the plantar surface of the foot for a relatively small deflection compared to foam laminate. This is assuming the plastic shell is designed to still significantly resist the applied force thru the entire range of deflection.

    This, one would imagine, would mean that the foam would allow the muscle action to resist the motion/deflection of interest instead of using excessive plantar force where it (the orthosis reaction force) may become pathological, to achieve the same deflection result. As the foam reached its steep curve range of deflection stiffness it can then begin to exert large resistive forces at a time where those applied forces may be pathological to the muscles and ligaments (approaching end range) and perhaps bone, were they soley allowed to resist applied forces.

    In the situation where the applied forces in the MLA are reducing or in a negative direction, at heel lift for instance, the energy hysterisis of foam allows natural foot progresssion without returning excessive energy and forces in the plantar vault at a time when they should be applied to the forefoot, which could even result in a rocker or see saw action over the fast returning plastic arch shape and again excessive and pathological plantar MLA force. It is possible to imagine that in the case of plastic the consistant and negatively linear application of high supination moments to the STJ via the MLA could result in lateral instability at the propulsive phase, whereas this seems highly unlikely with a foam laminate structure since moments will reduce exponentially with the concurrent applied negative force.

    The main point here is the force vs deflection curve. While there will always be the case of equal and opposite forces (that Ed has said many times is the convention his calibration technique is based on) and so will be the same regardless of material type or properties, the force deflection curve will however, be very different for different material properties.

    Since these techniques of interest are considering the kinetic vs kinematic relationship of the foot action thru stance phase, then it seems reasonable that the force vs deflection characteristics would be a better convention to base a calibration or graduation system upon. This I believe is the nub of Roberts soft and squishy technology approach. Which, by my experience, works very well in many cases I'll have you know. OK :boxing: :D

    How does that sound to you Robert?

    All the best Dave
     
  36. joejared

    joejared Active Member

    Setting aside the past 13 years of working with lab technicians, podiatrists and chiropodists, I'd have to refer to the journal of podiatry and medicine, I think. One of my customers mentioned that there was an article on this subject recently. As for my own opinion, I have to say that with prone casting using plaster, gravity is on the practicioner's side in helping to maintain the position of the foot during curing of the plaster, and less force is required to maintain the subtalor neutral position. For true 3D non-weight bearing scans, it's probably pretty close in my opinion, as there is no cure time and negligable time for scanning. Personally, I prefer anything that is non-contact or plaster over anything semi or full weight bearing, but having both methods, semi and non-weight bearing for comparison of fat pad expansion has its benefits. for producing an actual orthotic, however, I prefer non-weight bearing, for purely mathematical reasons.
     
  37. That sounds like the best and most coherent technical description of the concept i have ever heard!:drinks

    It is nice to see that our oft derided "theoretical biomechanics" can be used to rationally explain a simple concept that patients grasp intuitivly. Some patients get on better with insoles which feel soft underfoot, and putting something soft and coforming medial to the STA can provide substantial supintaion moments!

    Cheers M8:drinks

    Robert
     
  38. Hey stu

    Trying to post whilst looking after 2 small children so can't do this properly. But can i say how nice it is to see a well thought out and courteous post on this subject? Perhaps now we can have a proper conflab!. :drinks

    I'll get back to you

    Robert
     
  39. It wasn't me mister, it was one of my customers (which I endlessly talk about). That's me convinced then, as long as one of your customers says it the best way to cast, that's good enough evidence for me. BTW, that's got to be the weakest come back on a challenge to a statement ever. I personally think we should all be scanning the foot, for purely mathematical reasons?!? Not. Sell me a scanner, it's love time.
     
  40. joejared

    joejared Active Member

    You're confusing me with a dittohead, fwiw.

    That's not what I wrote. By mathematical reasons, I mean that contact scanning flattens out much of the foot data, deforming the fat pad. While you can't walk without deforming the fat pad of the plantar surface, non-linear regression abhors a straight line. While this was not so much of a problem with uniform distribution of data from my scanner, it was a major issue with contact digitizing of casts.

    As to publications, I've found the following links, but from what I can tell, I've walked into the equivilent of a religious debate on this point.

    http://www.podiatrym.com/pmarticle.cfm?id=94

    I happen to agree with the author because gravity is helping to stablize the foot during curing, but obviously there was no research cited there, just opinion. As to the reference from one of my customers, which appears to be a button pusher for you, I'll revise this response as soon as I have the information. We can agree that my prior statement should be considered an opinion both before and after the article reference is posted, because on this point, agreement is simply not possible due to many conflicting opinions in various papers.

    http://kenva.wordpress.com/2008/03/10/casting-for-foot-orthosesart-or-true-scientific-discipline/ References both this site and a statement made by Kevin Kirby, which I agree with but it doesn't support my statement, and actually provides alot of latitude either way.

    http://www.japmaonline.org/cgi/content/abstract/93/1/1

    suggests that although there are variances that the end result suggests that it doesn't matter after all.
     
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