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Plantar fascia groove

Discussion in 'Biomechanics, Sports and Foot orthoses' started by bstarkey, Jan 11, 2011.

  1. bstarkey

    bstarkey Member

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    Can anyone help me out with some guidelines on modifying a cast to insert a fascial groove on the orthosis?

    Byron Starkey
  2. Hi Byron,

    Use lipstick on the foot before casting to mark the prominent Plantar fascia


    check mark of the positive cast and take measurements of the lipstick of position, length and you will need to work out height of groove.

    modify cast

    add plaster which is the same length and height of the groove you want and in the same position as the lipstick was on your cast.

    when you press the cast on the positive the groove will accommodate the fascia.

    Remember adding a groove will increase the stiffness of the device.

    You can also add Plantar fascia grooves direct to the device by adding material medial and lateral to the prominent Plantar fascia or by grinding out material from the device.

    Hope that helps some.
  3. efuller

    efuller MVP

    In some pairs of feet the fascia is not symmetrical so marking the cast is important. Transfer that mark to the positive cast. Ink on the foot will work to mark the negative. Then you can ink the negative so it will transfer to the positive. That will give you a line on the positive that you may cover up with the expansions, so extend the line proximally and distally so you can find it. If the cast is dry enough you can glue a piece of cork to the cast to create the groove in the finished device.

  4. footdoctor

    footdoctor Active Member

    Hi Byron.

    Yeah depends on the shell material that you plan on using to fabricate your device.

    Take it your are using traditional positive plaster models yeah?

    If so, number of options for you. (some of which Michael has rightful pointed out above)

    1) Apply thin coating of lipstick/betadine ointment/mascara to full length of P/F band. Apply wet bandage, mold to foot, dry, strip off and remark on negative cast if need be just prior to plaster pouring stage.

    2) Incorporate/ add a plaster addition to the area marked on the positive cast. You can fold/roll up strips of p.o.p bandage instead if its easier for you. Getting the shape neat can be awkward and time consuming.For this reason I use a piping bag and thin nozzle (used in cake decoration/icing) Much smoother, neater and quicker.

    3)Heat and Vacuum Press shell as per usual.

    The other way is to use an eva shell material. finish the device minus the top cover, get the patient to pop in, apply staining agent (lipstick etc) to the p/f band and get the patient to carefully stand on the device. Remove the foot directly upwards to reduce smudging of the mark. Using a round headed sanding cap drill attachment, create a channel. As standard I use 1.5 cm (depth) then cover if required.

    Another way is to line the shell with poron/ ppt/ low density eva and apply the same technique as above.

    Hope this helps

    Epione Orthotics
  5. bstarkey

    bstarkey Member

    Thank you Mike, Eric and Scott for all your help, really appreciate it!!

  6. Boots n all

    Boots n all Well-Known Member

    Dont modify the cast.

    Try doing the casting with a foam impression box, you can then use a pen/finger to compress the lipstick marked channel into the foam before you pour the plaster.

    A big time saver as apposed to modifying another plaster cast
  7. bstarkey

    bstarkey Member

    Thanks, was going to ask about using foam impression box too.

  8. JB1973

    JB1973 Active Member

    hiy all
    i'm glad someone else posted that question as i've been meaning to ask for a while. What was a concern for me as well was how deep should i make the groove. it seems from the above posts that there doesnt seem to be a set depth. glue a piece on here, use your finger etc is a bit vague. Is it just a matter of trial and error and instinct?
    Its a bit like following a Jamie Oliver recipe when he says " chuck in a handful of this or a splash of that" his handful is never the same as mine! Subsequently i leave the cooking to my good lady and everyone is a winner
  9. JB it depends on how much the fascia is sitting proud as to how much groove you require.

    I read a few lab guides yesterday and most seem to recommend 1.5 to 3mm, but thats only a guide, but it will of course be different from person to person.

    If you start with a base height and if your using say 5 mm poly you have room to grind out 1 or 3 mm extra if there is still irritation. With EVA you have more to play with. Carbon or thinner material you will have to add Poron or the like medial and lateral to the proud Fascia, but it´s like all orthotic stuff its a bit trial and error.
  10. efuller

    efuller MVP

    Something will feel better than nothing, so it will be hard to get a just right number. Although it is not an area that I have experimented much. The first pair of devices I had hurt horribly because of lack of groove. They were great with a groove. My only experiment was to fill in the arch to the height of bump on the cast. These devices relieved my hallux limitus symptoms and had no groove, but a much lower arch. So, the height of the groove will be dependent on the amount of arch fill.

  11. CPedTechie

    CPedTechie Member

    Speaking as a lab tech who deals with many different fabrication and design requests, no one formula works for everyone. You can see similar results and outcomes from a variety of different orthotic styles.

    When it comes to plantar fascia grooves, take into account the thickness of the top cover as well. If you're covering the groove with 1/8" poron and then 1/8" neoprene, for example, you'll essentially be filling the accommodation with 1/4" of material.

    Would it not also be helpful to consider the flexibility of the MLA as well? If a hypermobile foot elongates, would you not make the PF channel longer to compensate for this, especially if working from a slipper cast? And what Eric just mentioned about amount of arch fill determining the groove depth makes me think. Would a higher arch support require a deeper groove to or would the higher arch reduce overall strain on the fascia not requiring a deep channel? My clinical experience is limited but this topic interests me. I haven't done any PF groove adjustments in recent memory, I was wondering what more of your experiences were with their effectiveness.

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