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. Everything that you are ever going to want to know about running shoes: Running Shoes Boot Camp Online, for taking it to the next level? See here for more.
    Dismiss Notice
  2. Have you considered the Critical Thinking and Skeptical Boot Camp, for taking it to the next level? See here for more.
    Dismiss Notice
  3. 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.

Types of orthotic

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Robertisaacs, Feb 9, 2009.

  1. Members do not see these Ads. Sign Up.
    facfsfapwca posted on another thread (on duputryns)


    In the words of the great DTT "I can't have that"

    Firstly, on the Amfit, Amfit is the system used to derive an EVA device. As a method for capturing the desired morphology it has its advantages and disadvantages, as do they all, but to state that they are not orthosis is, IMO clearly erroneus when one considers the definition of an orthotic!

    The statement that they are not as likely correct should surely either be prefaced with "in my experiance" or "the evidence shows" (in which case please produce it!) OR suffixed with an explanation of why you beleive this to be the case!

    Secondly on the insoles "made of soft crap". Once again you infer that a certain type on insole will not "correct" somebody adequately. Leaving aside that "correct" is dubious terminology at best in the absence of an established "correct" position to strive to, what rationale do you offer that orthotics made of soft materials cannot exert forces on the foot and therefore alter function?

    Kind Regards
  2. And another that seemed to show that more rigid casted devices didn't work the same if softy soft softs had been worn for a few weeks previously.

    As many of you are already aware, I'm pretty interested in surface stiffness. If we take the assumptions of others that we all spend our whole lives walking on flat concrete and that we have a shoe with a known sole stiffness, it would appear possible to make a flat insole to give us a net surface stiffness in the tuned surface range reported by McMahon. Would such an insole be "soft" or "hard"?
  3. pgcarter

    pgcarter Well-Known Member

    Hi Simon,
    When a discussion of stiff or soft orthoses starts there is another characteristic that I think matters....if you make an EVA that deforms easily but does not compress, as opposed to a shell device that resists flexion and deformation as always there is the issue of "tolerance" by the patient. And if you wish to "reach up" to the shape of a foot and have an influence on the nature of it's motion over a greater range of positions then it is very difficult to make a device out of EVA or poron that will do that and be tolerated by the patient.
    Very messy terminology in this area....the concept does not seem to get much air time and the dialogue of the ideas does not seem to have been explored and defined at this stage. I'd be interested if you know of any work done around those concepts?
    regards Phill Carter
  4. Phill:

    You may want to check out the newsletter I wrote over 10 years ago on this same subject: Shank dependent vs shank independent foot orthoses.
    Last edited: Feb 10, 2009
  5. lcp

    lcp Active Member

    i know the greenhouse thing is huge these days, but i want to know when soft crap had started being used as an orthotic material? must be tough to grind!! is it a combination of crap or certain species??
  6. Soft crap is quite useful when you run out of foam boxes for negative casting. Hard crap can be ground to different shapes, but generally requires the overhead vent to be on high for a few hours after grinding. Crap of variable density can be used as proprioceptive insoles and Dr. Rhubarb says it may aid in the cure of a prolapsed uterus. Who ever said that crap is such a bad thing??:rolleyes::drinks
  7. Wendy

    Wendy Active Member

    Kevin I like that..................................................very eco friendly in recycling..
  8. Steve The Footman

    Steve The Footman Active Member

    :eek: Is there someone who believes a Root orthoses is best? I thought there weren't any of them left anymore!

    I think the idea that something soft is not controlling is a misunderstanding that many people have (at least in my backyard). Kevin's Shank Dependent newsletter is one of my favorites.

    From Wikipedia:
    Stiffness is the resistance of an elastic body to deformation by an applied force. It is an extensive material property.
    Hardness refers to various properties of matter in the solid phase that give it high resistance to various kinds of shape change when force is applied.

    I think the misunderstanding between stiffness and softness/hardness is the key to this. It depends on each patients individual characteristics and needs which type of material will be best. A soft material like low density EVA may be comfortable on contact but be intolerable because of its resistance to deformation. At the same time a harder material like a graphite shell can feel less comfortable but will have less stiffness and be more tolerable as it moves through a greater range. It can go the other way too. The amount of stiffness and softness that is needed is dependent on the patient's needs.

    But just because an orthotic material is harder does not make it stiffer.

    I use many shank dependent orthoses in combination with the shank dependent nature of footwear. I think I get adequate control and more comfort for many runners. The softness of the material used does not prevent me from getting it wrong on occasions and creating an orthotic that is too controlling and intolerable for the patient.
  9. Mark Egan

    Mark Egan Active Member

    In my (limited) experience the type of material used in the production of an orthotic needs to be explained to the patient as many are not keen on the "hard ones" and usually ask why they can't have "soft ones". This is not helped by podiatrists placing in their adverts that they do soft orthotics - this drives me nuts when I see this.
  10. Hey Mark.

    Patient education is certainly a key element here when there are different types of orthotic available. In the NHS I often find myself explaining to a patient why they are not getting the device their neighbor / friend at school has.

    However I don't really see a problem with advertising that you do "soft" orthotics (or indeed a choice of types of orthotic). I feel rather strongly that there is a place for both in an effective biomechanical toolkit, if you advertise that you do conservative or surgical management of IGTN, or that you have the capability to do cryotherapy, why not advertise that you offer several types of orthotic?

    Just my view.

    Kind regards
  11. Mark Egan

    Mark Egan Active Member

    Hi Robert

    Maybe it is just me but I find the single statement of "soft orthotics" grates me, as I feel that simply indicating that you do orthotics should be enough in an advert. It should be then as you suggested considered with each patient what density/stiffness is most effective based on an effective assessment.

    I see your point about making the public aware of what sets you apart from others though i.e. cryotherapy etc.

Share This Page