Hi all,  Stanley wrote:

At 04:30 PM 1/2/2005 -0500, you wrote:
>This whole discussion started with comparing the effects of EVA and
>Plastic/Carbon fiber FFO's. Since we agreed that the Plastic/Carbon fiber
>orthoses do not change the calcaneal position, the thread turned to moments.
>Regarding Eric's nutcracker, it seems that if you do not get the nut then
>you are not using the nutcracker optimally. I think that if we do not
>change the position of the calcaneus, we are not changing the subtalar
>joint, only reducing the secondary pronation due to superimposed body weight.

Pronation moment is pronation moment.  I don't see how some pronation
moment can be primary and some can be secondary.  If you see supination,
when before the orthosis there was pronation, you do know that there was a
decrease in pronation moment (or increase in supination moment).  The
increased supination motion may be a good thing, but you may be going too
far.  Increased supination motion may lead to stress reaction of 4th or 5th
metatarsals.


>I think we should use orthoses more optimally. It seems that Kevin M.'s
>rock in the shoe will definitely change the heel position if placed
>correctly. I would hope we could do better with our orthoses.
>Kevin M. discusses manipulation for increasing subtalar joint eversion. I
>did this years ago and stopped doing it. I don't remember the reason,
>(probably my skill level was not high enough to recognize the reasons for
>the subtalar dysfunction and the therapy was only short lived), but I will
>revisit this. This brings up an interesting scenario. Let us say we make a
>plastic orthotic for a foot with Sinus tarsitis. Jeff or Kevin or Eric
>makes an orthotic to change the moments. Kevin M. manipulates the foot to
>increase the STJ range of motion, and the pronation is now stopped by the
>plantar fascia.

I agree that the plantar fascia can stop pronation, however other scenarios
can occur as well.  The center of pressure may be brought under the STJ
axis so that there is no pronation moment from the ground and hence no
plantar fascial tension is needed to resist pronation moment from the ground.


>  Now let us say that the plantar fascia becomes inflamed. Jeff or Kevin
> or Eric makes an orthotic to change the moments for this new foot. The
> orthotic will now be different than the earlier one, as this will also
> not change the subtalar joint, and the calcaneus will not change its position.
>Therefore wouldn't the Plastic/Carbon fiber FFO's really be doing next to
>nothing? Shouldn't we do better?

This was the point that I was trying to get at with the nutcracker
analogy.  With sinus tarsi pain the nut is just about to crack.  If you
decrease the squeeze on the nutcracker, both arms can still be in contact,
but the nut is not anywhere near cracking.  This is not doing next to
nothing, this is relieving pain.  If someone were to develop plantar
fasciitis after an orthosis made for sinus tarsi pain (I can't say that I
have ever seen this)  then you could add a reverse Morton's extension
assuming the plantar fasciitis is in the medial slip.  Yes, this orhtotic
is different, but it can still relieve symptoms without altering STJ
position.  Can you say that an orhtotic must cause supination to be effective?


Cheers,

Eric Fuller

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