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What would be an ideal prefab insole?

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Kursh Mohammed, Aug 11, 2011.

  1. Kursh Mohammed

    Kursh Mohammed Active Member

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    There are so many choices available out on the market, and more Podiatrists are using this option instead of custom made. A Yorkshire based NHS trust predominantly use prefab insoles (variety of different kinds) in comparison to custom made.

    So I have been thinking what do we all like about prefabricated types?

    What would make an ideal prefab insole?
  2. One that does the required job to reduce stresses acting on the desired area.

    Seems I maybe a bit grumpy today,
  3. Daniel Bagnall

    Daniel Bagnall Active Member

    Hi Kursh

    There is really no such thing as the ideal prefabricated orthotic. It doesn't matter what type of orthotic it is as they are all orthotics. As Mike said, it is a lot more to do with which prescription variables do the most effective job at reducing the pathological loading forces on the injured anatomical structure. For example, this maybe in the form of stretches, footwear modifications/recommendations, prefabricated orthotics, custom orthotics... etc

    It really doesn't matter what you choose as long as you can design a Tx regime to reduce the damaging forces.


  4. Craig Payne

    Craig Payne Moderator

    The ideal prefabricated foot orthoses will have the design features that can deliverer all of the prescription variables needed for each patient. In other words, there is not one that I know of that can do that, which is why I tend to use 3 different ones, some glue, some eva and a grinder to get most of the design features that are needed.
  5. RobinP

    RobinP Well-Known Member

    What makes you think that Mike? ;)

    I see what you are driving at Kursch.

    We all agree that the prescription variable that delivers the reduction in the tissue stress is the important element. What you are really asking is what would be the best vehicle to offer you the greatest choice of variables. You can't have an all encompassing prefab, but what will make it appropriate to the largest cross section of the population?

    How would we construct a prefab that was generic enough in shape to be close enough to match a large cross section of the population(debate ofver the importance of orthosis conguency to the foot aside)

    What are the most important prescription variables that the prefab can offer?

    How many variables can be offered withoutmaking the structural integrity of the device an issue?

    EVA/PU/polprop? Which gives the best scope for customisation of the shell?

    Is it better to have pre made additions that can be stuck on with double sided tape or is it better to just have a flat base with square edge to adhere additions to?

    Looking at the current prefabs, I would have to say that the Interpod control tech flex with the new cover is a pretty good all rounder. It covers a lot of bases. The danger is that, in offrering soemthing with a massive variablity of additions and prescription variables, you run the risk of making the cost of the device high enough that a library style semi bespoke device becomes a better option eg Salts performer Range at £40 approx per pair

    More questions than answers
  6. Lab Guy

    Lab Guy Well-Known Member

    I agree with the comments of the above posts. In addition, I think for the Podiatrist in private practice that the prefab should be high quality yet inexpensive and only sold to Podiatrists for price control. It does not look good when your patient is paying more for a product in the office only to find it much cheaper with a google search.

    I also like the EVA wedges that you can cut and stick on the bottom of prefabs and patients like that your modifying their prefabs for their particular problem.

  7. JW326

    JW326 Welcome New Poster

    any thoughts about d3o in an insole?

    Last edited by a moderator: Sep 22, 2016
  8. RobinP

    RobinP Well-Known Member

    I want some d3o just to play with let alone put into an orthotic;)

    Interesting idea though. I suppose it would depend how much force it took for the material to react as to how it would work within an orthosis. Or rather if the reaction to force was on a sliding scale of force input = increase in the molecular activity causing the material to increase in stiffness
  9. Orthican

    Orthican Active Member

    Elastohydrodynamic.....I have used similar materials a long time ago but it was called "P.Q" liquid polymer. A part " A" and "B" are mixed together to get the required durometer. The nice thing was that you could play with different mixes for different areas of the foot in the same insole if one was technically savvy.

    Bad part was the materials prior to set were quite toxic.
  10. Non-newtonian polymer. Has been done.;)
  11. RobinP

    RobinP Well-Known Member

    As part of an orthosis?
  12. yes..
  13. blinda

    blinda MVP

  14. David Smith

    David Smith Well-Known Member

    Q) Who would be the ideal wife

    A) My one, the one made for me.
  15. David Smith

    David Smith Well-Known Member

    Although Kelly Rowland would be a good all round compromise if you had to pin me down to an off the shelf one size fits all wife :D
    Last edited: Sep 23, 2011
  16. David Smith

    David Smith Well-Known Member

  17. Not random. Me colleague was referring to the non-Newtonian properties of custard.
  18. David Smith

    David Smith Well-Known Member

    I know, just imagine custard filled shoes - comfortable and delicious
  19. David Smith

    David Smith Well-Known Member

    Just to be helpful

    I've used allsorts (but not liquorice) but always come back to Vasyli - However, at the moment I am using Talar Made Architec EVA, they are not posted at all but come with separate adhesive medial posting and heel lifts. They also come in two densities, they can be used and cut and ground (grinded) in all types of imaginative ways but at least you can start from a base line non posted position unlike many OTC that have medial posting built in. National Orthotics also do a similar EVA product but only 3/4 length but what is useful about them is that they have a medial skive designed in to them and come in 3 densities and they are very cheap, I would recommend both of them as an excellent product and probably very useful for quick turnover and maximum effect in the NHS clinic.

    Dave Smith
  20. Rob Kidd

    Rob Kidd Well-Known Member

    When the going gets tough, go back to basics - advice from Colonel Herman Potter - got to be good advice. At the end of the day, common things are common and rare things are rare. Since rearfoot varus (are we allowed to call it that these days?) is more common than all else put together, at the of the day, the prefab insole would be posted at the hindfoot by about 4' inversion, have an arch support, be made of eva and be machine washable. Easy really. One size does not fit all, but it goes a long way towards it. Rob
  21. David Smith

    David Smith Well-Known Member

    Doh!:bang: :bash: Is this 1966? Decades of brilliant research and researchers dismissed in a paragraph.I going back to being a milkman :rolleyes:

    Luv Dave
  22. Admin2

    Admin2 Administrator Staff Member

    Professor Isaacs describing non newtonian polymer
    Last edited by a moderator: Sep 22, 2016
  23. JW326

    JW326 Welcome New Poster

    I'm not a professional as you will probably conclude, I just find what you guys do to be very fascinating. This is my understanding of how insoles work based on experimenting and reading. I read that a forefoot valgus wedge will shift the center of pressure more towards the lateral side of the forefoot during propulsion (which I have experienced). but I've also experienced that this only occurs when there is no gradual support along the calc-cuboid leading to the valgus wedge in which case it would act as a reverse forefoot varus wedge. Am I wrong? The same applies to the varus wedge.. if there is no gradual support it only applies more ground force to the area lifted or wedged.
    If this is how insoles work and if the reaction to material like d30 has a higher viscosity when more force is applied to it... my question is....if you have a insole with a forefoot valgus wedge.. and d3o (or some dilitant) acting as the support under the calc-cuboid, a supinator would apply more force towards that area causing the d3o to act with a higher viscosity which would act as a the support reversing the forefoot valgus wedge effect of a more lateral CoP and ultimately compensating the supination. However, a pronator would not apply as much force to the calc-cuboid area during mid stance leaving it at a low viscosity (no support) causing the forefoot valgus wedge shift the CoP laterally compensating for pronation.

    would this work? please dont get too complex
  24. It's the rate of loading which is key, not the load per se.
  25. JW326

    JW326 Welcome New Poster

    whats the equation for rate of loading?
  26. It's the slope of the force time curve, change in force / change in time
  27. RobinP

    RobinP Well-Known Member


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