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Improving casting

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Admin2, Mar 30, 2006.

  1. Admin2

    Admin2 Administrator Staff Member


    Members do not see these Ads. Sign Up.
    Prolab in their latest Orthotic Communique have some interestig snippets of advice:
     
  2. Craig Payne

    Craig Payne Moderator

    Here is my check list:
     
    Last edited by a moderator: Mar 30, 2006
  3. Kenva

    Kenva Active Member

    The thumb print

    Is there a guideline to the position of where the lateral thumb print should be? and why?
    Is it on the 5th met head,
    Is it on de 4th and 5 met head
    Is it just proximal from the 5th or 4/5th
    maybe others

    We take our prints behind the 4/5th met head because direct pressure on the 5th met head would influence the FF-RF relationship... There is more soft tissue right behind the met heads.

    anyone some advice?

    tnx

    Ken
     
  4. Mariusz G

    Mariusz G Welcome New Poster

    Quote:
    Improving Orthotic Outcomes with Casting

    Do you critically evaluate your orthotic outcomes? Are some of your timesaving steps negatively impacting your outcomes? Proper negative casting can affect orthotic outcomes. Take a moment to consider small changes in your casting and cast preparation that may improve your orthotic therapy success:

    - Plantarflex the 1st ray to its end range of motion (ROM) when casting to increase 1st MPJ dorsiflexion and decrease 2nd metatarsal pain

    - Cast the foot "loaded" (dorsiflexed to the end of its ROM) to assure optimal position of the foot on the orthotic during weightbearing

    - Evaluate the negative cast to assure that there was good contact with the plantar surface and that the foot was not in an abnormally pronated or supinated position

    - Place the cast on a table to determine whether you have captured the foot's forefoot-to-rearfoot relationship. Compare the foot and the cast to ensure that they match.

    - Mark the "problem" areas on the casts as well as on the prescription form. This will assure that sweet spots, plantar fascial grooves (PFG), and other accommodations are placed correctly. Don't oversize the markings for the lesions or hot spots.

    Remember, a great cast is the first step to great orthoses.

    --------------------------------------------------------------------------

    Could someone explain to me how one can plantarflex the 1st ray to end of ROM without introducing a greater FF valgus? When the cast is placed on the table (as suggested) it is more likely to sit more inverted than the measured FF valgus, is it not?

    This is how I used to cast with, at times, very unpredictable results - I now blame the increased valgus FF. Presently, I plantarflex the 1st and 5th rays, as per discussions with Bruce Williams and must admit the overall results, both comfort and effectivnes of the resulting orthoses, have greatly improved. It seems to me that by pl-flexing the 5th ray the increase in valgus position is not as drastic, thereby more closely resembling the FF to RF position.

    Thanks,
    Mariusz
     
  5. penny claisse

    penny claisse Member

    Any tips for negative casting that increase the comfort of the high arched foot?
    Also why do I often find that when I take a truly representative cast of a substantial 'inverted' forefoot to rear foot position, that has resulted in a large relaxed rear foot valgus stance position - I get an orthotic that often fails to adeqately correct the problem? How can I improve my casting to avoid this? or is it all in the prescription?
     
  6. DaVinci

    DaVinci Well-Known Member

    Get the lab to add a large plantar fascial groove in the shell.
    Sounds like you not casting out the forefoot supinatus. Plantarflex the first ray and/or dorsiflex the hallux during casting.
     
  7. achilles

    achilles Active Member

    Dear All,
    I am interested in your casting technique when applied to a child with a medially deviated STjt axis and joint hypermobility is present.
    How do you load the forefoot without pronating the STjt or creating abduction at the MTjt?
    The reason I ask, is that I tend to stabilse the calcaneus and prevent navicular drift whilst loading the forefoot.
    What say you??
    regards
    Tony
     
  8. nicpod1

    nicpod1 Active Member

    Just to add to Tony's piece, how do you cast a foot, without creases in the cast, whilst plantarflexing the 1st ray, loading the 4th/5th met (not to mention plantarflexing the 5th ray if this is what some people are doing), whilst, as Tony says, preventing a STJ pronated position and, therefore, navicular drift? I'm afarid I've run out of hands!

    I've had loads of difficulties casting hypermobiles or other difficult feet whilst trying to fit all these other bits in! Especially if the width if the foot is larger than the capabilities of my hands (typical woman!)! I feel that it is leading to more problems in some cases and have taken to only plantarflexing the 1st ray when it is definitely needed as in tib post dysfunction patients.

    Instead I have been putting 1st ray cut-outs into the ones that need more Hicks windlass, espcially runners, which has done brilliantly (so long as there's enough proximal valgus support).

    How can you plantarflex the 1st and 5th rays, whilst maximally dorsiflexing the ankle and mimicking load-bearing anyway?! Perhaps someone could video themselves doing this and post it on the site?
     
  9. penny claisse

    penny claisse Member

    This debate on casting the foot is really intriguing!

    'Just to add to Tony's piece, how do you cast a foot, without creases in the cast, whilst plantarflexing the 1st ray, loading the 4th/5th met (not to mention plantarflexing the 5th ray if this is what some people are doing)'

    It occurs to me that if you have a large forefoot supinatus and you plantarflex the 5th ray as well as the 1st you will then recreate the original position? How can this help to 'cast out' the supinatus?
     
  10. achilles

    achilles Active Member

    "It occurs to me that if you have a large forefoot supinatus and you plantarflex the 5th ray as well as the 1st you will then recreate the original position? How can this help to 'cast out' the supinatus?"

    Not really sure why you would wish to plantarflex the fifth ray :confused:
    You are absolutely right that plantarflexing the 1st ray will create creasing of the skin. To prevent this, it is possible to dorsiflex the hallux, gaining reciprocal plantarflexion of the 1st ray, although I find this difficult when controlling the rearfoot personally.
    I feel it also inportant to mention that 1st ray plantarflexion effectively raises the height of the medial arch, which needs to be taken into account.
    Again I feel this can be useful as it can increase the supination moment of the orthotic.
    regards
    Tony
     
  11. footdoctor

    footdoctor Active Member

    push,push it out!!!!!!!!!!!!

    hey mariusz,

    Your right if you plantarflex the 1st mpj when casting you may in some situations pf the 1st abnormally. In my mind the only time I plantarflex the 1st is when I have a f/f supinatus or met primus elevatus and dont want my device to be incorrectly posted as usually the f/f-r/f will decrease when you reduce the pronatory force on the hindfoot.

    Got a supinatus push,push it!!!!!


    scott
     
  12. footdoctor

    footdoctor Active Member

    prescription variables

    hey penny,

    If you've taken a nice cast look at the prescription.Minimal arch fill,+4 degree varus rearfoot post,medial skive,medial flange,rigid shell construction proximal arch,thin distal arch,1st met cut out.

    It's all about shifting force laterally,try these measures.

    Good luck,

    scott
     
  13. Craig Payne

    Craig Payne Moderator

    You can't - you have to rely on the lab to smooth it out.

    CP
     
  14. footdoctor

    footdoctor Active Member

    A lot of talk about plantarflexing thr 5th ray here which is difficult unless you have an assistant,why not just instruct the lab to remove some of the plaster from the lateral-plantar border instead.

    scott
     
  15. davidh

    davidh Podiatry Arena Veteran

    I'm not sure that all these moves are necessary. Take a reasonable cast, use a good lab, don't worry if you have to do some post-fitting mods. I'm sure we all have to do this from time to time.
    With hypermobile feet I find it helps to place a couple of fingers (of the free hand) on the navicular.

    I often find (when teaching others to cast) that basics, like good plaster control, have been overlooked. Casting need not be messy :eek:

    But for me the essence of a halfway decent cast is, "does it resemble the foot?" and "can I see a FF to RF difference?"
    Regards,
    Davidh
    (world's worst caster :) )
     
  16. Kenva

    Kenva Active Member

    Is there no consensus on that thumb print of mine? We're talking about plantar flexing the 5th ray/1st ray...

    is there any literature on what cast-adaptations to make in certain pathologies? Here and there you can find something (if they aren't contradictory) but no key-reference...

    tnx
     
  17. markleigh

    markleigh Active Member

    Correcting supinatus

    This may have been covered elsewhere (& yes, I have looked but can't find). The majority of forefoot varus deformities are a supinatus. And I gather from what I can find, this should be corrected when casting? Is that correct? If so, is this acheived by plantarflexing the 1st ray only or attempting to almost I guess rotate the forefoot down to balance the rearfoot. Probably dum questions to many of you.
     
  18. markleigh

    markleigh Active Member

    Sorry, I perhaps didn't look far enough as I found at the bottom of the screen, an answer to some of what I was asking. Apologies.
     
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