Podiatry Arena members do not see these ads

Hi All.

I have always questioned the effectivness of a hard orthosis in a soft jogger / soled shoe, since the distal edge over time seems to dig into the shoe. Does this reduce its effect?
I prefer to put a FF platform to increase the surface area or use an off the shelf with added wedging which sits evenly on the top of the sole material and not dig in over time.

Any thoughts?

Cheers

Joe

Soft insoles/sockliners in shoes will allow the orthosis to evert or invert inside the shoe slightly. One way to significantly reduce this effect is to add a noncorrective forefoot post to the shell of a shank independent orthosis or to use a shank dependent orthosis.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

My two cents worth consists of saying that for some feet to get the effect you need you will need to use a "plate" style device made from rigid but flexible stuff like polyprop as opposed to a flexible but hard substance like EVA.

I have found that if you do a suitable differential grind to heel and anterior border and the things you and Kevin have said the problem will not be that severe...if the shoes are that insubstantial then they are probably not very good for the kind of foot that needs a shell device, and if you mean running shoes...by the time the device has ground its way down into the shoes, the shoes have probably done enough miles as running shoes.
We do practice in an imperfect world using materials that are not always ideal....which is not to say we should not always look to make things work better.
In the fifteen years I spent fitting skiing and walking boots I regularly saw footwear with widely differing hardness/density of midsole, and plate orthoses always make more impression on softer midsoles....and this effect actually tends to "wash out" the effect of the orthosis, the device is sitting on a less precise and more forgiving layer underneath.
The result for the patient is more controlling and more prominent feeling orthosis on a harder and more rigid midsole.
In gait sports I find no great need to alter the shapes I make as long as the body weight and forces are still high enough to actually flex the plates somewhat, rather than be held totally rigid by them.

I do find the need to alter the shapes I make in ski boots, for some feet for xc skating you have to be very careful with the angles and rigidity under the medial slip/anterior neck of calc area.
The focussed and repetitive nature of the action required for efficient skiing removes some of the natural opportunity to vary plantar pressures from stride to stride which has shown up with use of things like the pedar systems in walking and running. So in skiing you can't really "rest" tissue under foot from one stride or turn to the next because if you do the equipment won't work properly or as efficiently. Hence the need to watch your shapes a little, modified by foot type of course.

Regards Phill Carter