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Podiatech (Sidas) insoles

Discussion in 'Biomechanics, Sports and Foot orthoses' started by phil s, Jun 18, 2011.

  1. phil s

    phil s Active Member


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    Just wondered what people thought of these footbeds: especially for use in private practice.
     
  2. RobinP

    RobinP Well-Known Member

    I hope this is taken in the way that it is meant which is non accusatory and with genuine interest.

    Why "especially for private practice" ?
     
  3. phil s

    phil s Active Member

    Hi
    Just for personal reasons as i'm researching into insoles for when I set up my own practice.
     
  4. RobinP

    RobinP Well-Known Member

    I suppose what I was saying was, "especially for private practice" suggests a difference in prescribing based on someone being a private patient or a health service(or equivalent) patient.

    Why would this be the case? (Not saying that this is wrong, just curious to know the rationale so that I can offer what experience of the system you are suggesting)

    Robin
     
  5. phil s

    phil s Active Member

    Well on face value, Podiatech seem to be a good system for building insoles while patients are still on site: and changes can be easily made to them if required.
    Have you had positive results for a wide range of patient problems?
    Did you consider other systems? Why did you decide on Podiatech?

    Thanks

    Phil
     
  6. Not much. Personally I'd avoid it like the bubonic plague. But that's just an opinion.
     
  7. Craig Payne

    Craig Payne Moderator

    Articles:
    6
    Can the system deliver the design features in foot orthotics that you need to achieve what you want in patients? If it can, then use it.

    I do like some of their 'blanks' for use in restrictive footwear (eg sprinting; cycling; football footwear)
     
  8. RobinP

    RobinP Well-Known Member

    It depends on how you intend to use the system, in my opinion. The way in which I think you intend to use it is not great in my estimation. I presume your plan is to use the silicone pillows to get a position, heat up the blanks and mould accordingly? I think there are serious limitations with this , not least of which is trying to get a device that doesn't look like a dog's breakfast.

    If, however you take a cast/foam box and do a positive model, modify the cast then vac form and add posting, then in my opinion, it is quite a cost effective way way of making a custom device. The material reinforcement allow you to be quite in charge of structural rigidity/flexibility. Also, they are generally well accommodated in footwear.

    For the time involved in that approach, you could do similar in EVA. Might not look a fancy though which use where it being a private patient it might make a difference to you. I think a good thing if you are liking for quick turnarounds is a library style system. Salts performer system is very good.can be totally customised to your needs and you can have several sets of your own shell types. Not immediate though.

    Either way, what Craig said is the crux of it.can you deliver the prescription variable with what you intend to use? For a large percentage of cases, the answer is probably yes, and for those that you can't, you doo it the way you have always done it. Looked into it myself and decided it wasn't for me, but you might be different.

    Hope this helps.
     
    Last edited: Jun 19, 2011
  9. LOL
    Here's the thing. Lets break it down.

    1. Surface topography.

    I think it gives poor control here. You can't actually see what the plate is doing, on account the foot is on top of it. You CAN modify it post shaping, but nothing you can't do with a globotec. And shape wise you're basically limited to shapes you can manipulate the foot into, in WB. Also because of the pneumatic beanbag thing you have no base plane, and we KNOW that casting is more repeatable when you have that.

    2.
    Load deformation
    Any colour, so long as its black. Any stiffness so long as its available in a blank or can be "backfilled". Any material so long as its a low temperature thermoplastic.

    3.
    Friction
    Yeah. Whatever you want to cover it with. But you have to go to the embuggerance of doing that yourself. Or stick with what's offered.

    4.
    Ping factor
    Hmmm. One stop shop is well and good. But how impressed are patients going to be with a device you knocked up in front of them? I can see there being limitations there.

    5.
    Weirdthotics.
    Not really.

    I know one CAN make a working device with the thing. I've even done a few. But its a very expensive system, it gives limited options and ties you to not that cheap blanks. If I had that kind of cash to splash I'd want either a really loud ping or a really flexible system.

    Compare that to the performer system from techstep which for £20 more or so per device, and virtually no initial outlay, gives you damn near infinite flexibility, Dogs bollocks materials which will last forever and whatever mods you want incorporated into the design (rather than stuck on as an afterthought. Twice the price (or a bit less actually) but 4 times the orthoses.

    If I had a quid for ever Sidas I'd had brought in which had softened and died within a few years... well without hyperbole I'd have enough for a really nice meal. The longevity ain't great.

    Its not a BAD system. I'd call it a mediocre system. But If I was splashing out for something like that, I'd want more than that. I'd say its at the top end of the pre fab type option but measures poorly against the "real" custom systems.
     
  10. Arran2010

    Arran2010 Welcome New Poster

    This is my first post, so I hope the 'quote' has worked properly!

    1. Would you want to manipulate the foot any more drastically than a position suitable for weightbearing? After all, the footbeds are going to be used while weightbearing?

    2. I would also question whether using the same orthotic for longer than a few years would be suitable anyway? In this period a person's flexibility, strength, level of activity etc will usually change. Therefore, does the footbed 'prescription' not need to be re-assessed and altered accordingly?
     
  11. dazzalyn1

    dazzalyn1 Member

    Hi, I've never posted before(for fear of being 'shot down in flames'ha) but I've been prescribing Sidas for about 3yrs so couldn't resist.
    1. Pts love the fact they can leave the clinic an hour or so later wearing them.
    2. I don't 'knock it up' in front of them, the bench grinder is out the back (H & S)
    3. I explain part of the cost is my skills in assessing/casting etc and part orthotic, I also tell them the orthoses won't last forever (about 2yrs average).
    4. I don't try to make them for anyone that I can't lift the arch with 2 fingers (as per Robert's explanation in another thread).
    5. I get a heck of a lot of Pts come in clutching bulky or too rigid and uncomfortable orthoses that they cannot wear.
    6. Great feedback from Pts with arthritis, knee/hip joint replacements, many walkers that reported they went from hobbling e.g. 2 miles to painfree 10 miles. Pt recently reported 'its like walking on carpet with really a good underlay'.
    7. Lots of repeat business for 'another pair cos I can't be bothered to swap from shoe to shoe'.
    8. Great for PF, achilles tendon discomfort, anything needing shock absorbing with control.
    9. I use only a few components in manufacture, the Confort footbeds, the long heelcup, which is stuck to the base, it's the part that softens in the vacuum former and takes the shape of the heel and arch from the cast, intrinsic arch supports which I use as extrinsic arch fillers! and occasionaly rearfoot posting.
    10. In 3yrs I've refunded 1 pr, and remade 3prs. Hubris on my part, had so much good feedback that I started to get over ambitious in what I thought could be acheived.
    p.s. Don't know about startup costs as the kit was bought by the company I work for.
     
  12. phil s

    phil s Active Member

    Sounds like you've realised the limmitations of the system and exploited the legitimate uses of the footbeds without making any outlandish claims. Have you added your own more "functional" materials to the insoles? I.e hard EVA wedges?

    Phil
     
  13. dazzalyn1

    dazzalyn1 Member

    No I haven't, naturally I've considered what I would like to add but it would be experimental and I'm only supplied with certain materials from Sidas. Also Pts are only booked into clinic for just over an hour, that's to take a history, MSK evaluation, give/demonstrate exercises when tight muscle groups identified, footwear/foot health education, explanation of condition, discuss e.g maybe referral to GP for further investigations, physio etc, vary routine at gym etc to name but a few. Then 'knock it up', grind it around, fit to shoe, take Pt for a walk to evaluate comfort/give wearing in advice and book in for 6wk review.
     
  14. Sorry for the delay gents / ladies. Been enjoying a weekend of sunshine with the small peeps. Its a vice of mine which drags me away from PA now and then. Also I'd thought I'd replied once but must have gotten tangled in the ethernet somewhere.

    Welcome to the thunderdome. :drinks

    Absolutely. Why not?

    How do insoles work ? (Damn I'm channelling Spooner again!)

    Hmmm. Not so sure on this one. If I want to change someone's prescription because they've changed, then it'll be because they've changed. That's a different reason than "because they've worn out".

    We might have a completely different discussion on how we should change prescriptions to fit a 2 year change in, for eg, a 50 year old's strength, and how you're measure / gauge that. ;) . Another day.

    I hope you stick around Arran, and enter dialogue. Know that although it can seem rough here sometimes, its always in the name of education.
     
  15. And welcome to you also. We're just poppin cherries left and right today! Would never dream of flaming anyone.

    Agreed

    Well yes, obviously not in front as in 9 feet forward and one left. But nonetheless with pre fab systems of any descriptions, and sidas, there is a tradeoff between convenience and the amount of physical effort which appears to go into production. In the NHS people don't pay for their insoles. As such they don't value them as highly or follow advice as well as those who do. There is a downside to conveniance...

    Very wise.
    Ditto.

    I forget that one! I can imagine with some backfilling and a bit of imagination you could probably pull a lot of stiffness with sidas so not necessarily a limitation you should place on yourself.

    Caaaaareful. :rolleyes: That has nothing to do with anything. Other systems flawed does not = my system good.

    Very nice. We all like our systems or they'd not be our systems.
    No it isn't. ;)

    Not saying its not a system which can't get good results, it clearly can. But it would not be my choice is all. I know a few people who use it and love it.
     
  16. Sorry, couldn't let that one go. What's a functional material?!
     
  17. RobinP

    RobinP Well-Known Member

    I was going to post some comments in addition to what Robert had written but I would be duplicating so I won't bother. Some good questions to answer there new posters.

    Robert, you are a fairly frequent user of EVA if I am not mistaken? What sort of durability so you expect from these. Because you see more paeds , do you find that the the durability is less of a factor in your prescribing? For adults, are you more inclinied to use more durable materials so long as it is apprpriate to the prescription?
     
  18. It depends :rolleyes:;)

    There are several factors to consider, (you know most of this Robin, but for anyone else).

    Medial wrap.
    If I'm treating someone with a low navicular drift, I'll do a low medial flange. That being the case the ORF is almost entirely from compression of the EVA in a shank dependant device. Even Low density EVA bottoms out very little with direct compression. Shank dependant High density EVA will bottom out a negligable amount and thus will last almost for ever.

    Whereas a device with a higher medial wrap for a more horizontal ORF vector in a foot with more of a navicular drift will rely more on the tensile strength of the EVA, and the fastening of the show. So the durability will depend on those factors as well, but I don't expect it to last as long.

    Shank dependant / shank independant.
    Obviously if you have a void under the insole then it behaves as a shank independant device and the tensile strength of the material will be the first thing which defines the load deformation. If not it will behave as a shank dependant device and the compressive resistance will be what defines load deformation. The latter will change sooner than the former.

    Density and I think the temperature its cooked at are also significant.

    Yes.
    Yes. I'm also more inclined to use more durable materials with private patients.
     
  19. Odd why would NHS v´s private help you decide this ?

    Also since material/device stiffness is one of the important features I´m wondering if 2 differing material used to make a device lets say EVA and Poly have the same stiffness - would they breakdown at a different rate.

    I would not think they would - an for arguments sake why would you presribe different stiffness of device between patient groups ?

    If we had a Eva deive and a pOly device most would say the Poly is more durable material but if the EVA is shank dependent and they have the same stiffness I would say they break down at the same rate - so stiffness the key again - and if you agree Robert why ? to my 1st question

    ps sorry for the interruption again ;)
     
  20. For eg.

    One of my favourite prescriptions is a laminate of 6mm plasterzote over 6mm of high density EVA. The plasterzote moulds to the pressure profile of the foot and is soft to the touch, the EVA gives a degree of firmness and shape. So load deformation wise, we get an initial softness, followed by a stiffer section as the EVA flexes, followed by a stiffer yet segment as the EVA hits the shank and the LD becomes dictated by the compressibility of the EVA rather than its flexibility. Nice device, especially for rheumatoids and pressure intolerant patients.

    Only trouble is, the plasterzote bottoms out and becomes pretty much useless after 6 - 12 months (depending on the weight and activity of the wearer).

    In PP, I struggle to tell a patient that I want to charge them £200 for a device which will need replacing twice a year! Whereas low density EVA, shank dependant, with a 3mm poron cover will last much longer and give a not disimilar load deformation pattern, closer to, but not exactly what I want.

    I like soft in orthoses. I think soft is much under-rated. But soft usually comes with a tradoff of less robust. I'm much happier to spend the NHS' money on this tradeoff than the patients. Especially when the patients I like to use soft materials on are often the elderly ones who may have less money to spend.
     
  21. Soft- hard I would say stiffness - I think you can get the same stiffness out of whatever material your using - thin enough Poly will have the same stiffness as Plasterzote.

    Just a point I return back to the normal channel...........
     
  22. Can't get the same conformability though. And to get the same Load Deformation out of poly as plasterzote that would be the only material you could use. You can't have a pz thinness layer of poly floating 6mm above a thicker layer, etc.

    I like laminates because you get to have different segments of a LD curve reacting in a different way.

    I'd say softness is not the same as stiffness. Stiffness, to me, refers to the deformability of the entire unit. Softness, more about how the surface of the material responds to different areas of compression across its surface and how it conforms around peak pressures.
     
  23. We know how the measure stiffness, How do you measure softness or hardness ?
     
  24. Good question!
     
  25. I would say you don´t measure softness or hardness you measure stiffness.

    A device will have different stiffness at different points and using 2 or more materials we would be looking at the net stiffness of the device. with each material having different stiffness or even the same I guess could occur

    So we would be using Hookes law and youngs elastic modulus - which is all in relation to stiffness - I would argue that softness in a more elastic material ie less stiff and a harder material is less elastic and stiffer.
     
  26. For anyone who cares - here something I just came across.

    re Young, Hooke law, material elasticity, stiffness and load deformation and the like

    MECHANICS OF MATERIALS
     
  27. But stiffness is not the same as hardness. Hardness can be measured by shore durometer, although that does not really satisfy our needs because it ignores things like elasticity and the speed of compression. But that is a very different beast, for our purposes, to stiffness.

    Depends who's looking and why...

    Depends what we're measuring and why.

    Here's fun. I have a piece of poron, 20mm thick and a piece of poly resting across two blocks of wood with space underneath it. If i press my knuckle into the poron with a force of 10kg, it sinks 10mm into the poron. By a strange twist, the thickness of the poly is such that if i press the same knuckle into that with 10kg of force it flexes by 10mm.

    If we measure them both using stiffness they should come out the same, not so? same force, same deformation

    Will it feel different pressing into the poron as opposed to the poly? Yep.
     

  28. and what is shore durometer - elastic behavior of material or stiffness - http://en.wikipedia.org/wiki/Shore_durometer

    http://en.wikipedia.org/wiki/Viscoelasticity
    Depends who's looking and why...



    Depends what we're measuring and why.

    feeling different does not mean they have different stiffness.
     
  29. No. But it does mean they ARE different.
     
  30. Yes, the materials have different Young's moduli and different frictional characteristics, different thermal conductivity- what else might make them "feel" different?
     
  31. RobinP

    RobinP Well-Known Member

    Material Structure.

    open cell vs closed cell?
     
  32. This should be accounted for in the Young's moduli and other factors that I listed.

    Question: if we constructed two orthoses with identical load/deformation, friction co-efficients and geometry at the foot-orthoses interface would they feel different under the foot? If so why?
     
  33. I'd say no. Because load deformation characteristics covers both stiffness and hardness.
     
  34. Do the thermal properties make a difference to how something "feels"?
     
  35. Yes.
    Quite important as well IMO.

    Should thermal variables be added to the 3?
     
  36. Depends. How might the thermal conductivity influence the manner in which an orthosis works?
     
  37. Depends on whether we count the way orthoses work as purely mechanical.

    How do the thermal element of the environment affect, for example, inflammatory arthropathies?
     
  38. It comes down to whether the thermal conductivity properties of the device significantly alter the temperature of the foots environment, i.e. the within shoe temperature. If they did, you could make arguments regarding sweating and frictional co-efficient changes. You might also argue regarding vascular responses.

    The question is, how much variation occurs in the in-shoe temperature due to the thermal conductivity properties of a foot orthosis? Try this, Rob: Get a digital thermometer- I used to do this with the 1st year students using a fish-tank thermometer from Maplins it had a sensor attached by a long wire leading to an LCD display, the sensor was relatively small and could be placed under the MLA. Exercise (I know thats a dirty word for you) at a specific intensity for a specific duration (walk on a treadmill for a specific time at a specific speed). Measure in-shoe temperature with orthotics with different thermal properties. Let me know what you find.
     
  39. Cheeky git. I exercise. Beer doesn't just jump out of the fridge you know!

    That is a good study actually. Easier with two sensors.
     

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