FO posting responses

FO posting responses

zach harvey

4/23/2002

Thanks to all who responded. I plan on enlightening myself with some of

 these resources for posting/ wedging of foot orthoses... Zach

____________________________________________________________________

 Original question:

I am looking for information regarding the use of posting for foot

orthotics. I've done some reading but am still a bit confused as to how to

determine the degree of posting and when to post the forefoot vs. the rearfoot.

Obviously, the idea behind posting is to limit motion in order to protect the

foot, but I'm interested in knowing methods people are using to objectify this

process. I will post the results (no pun intended!).

Zach Harvey, CO

 _Responses:____________________________________________________________

Do a search on Tom McPoil, he has done more research

on feet then anyone I know. I have heard him speak

several times and he is extremely well informed. He

also does research for Nike or Reboc.





Though it is by no means the last word on posting, you may want to take

the course (if it's still being offered) When the Foot Hits the

Ground, Everything Changes. It's a good intro into how to look at the foot

and what happens to different foot structures when they go from open to

closed chain. It's the basis for posting though they don't give a how

to on fabrication. They assume you will take the impressions, measure

the degrees needed, and send them off to a lab. I do have some problems

with their techniques because you don't know if the lab will interpret

your measurement the way you specify. If you do it yourself, you need to

figure out how to put the information into practice.

 And, if I may, I'd like to suggest that FOs are Foot Orthoses or Foot

Orthotic Devices. I think our profession has fallen down on the job as

to allowing the name of our profession to be used to also name one

specific orthotic device without a peep of protest. The last time I looked

in Webster's, orthotic was still not listed as a noun.



Harold Anderson, CO



The posting of foot orthotics is not strictly scientific and there are

many rules of thumb in use. From an engineering perspective, the number

of degrees of rearfoot posting will depend on the width of the plantar

surface of the heel. Thus, the wider the heel the more wedging required to

achieve the same degree of posting.

 As a basic rule: each 1 degree of posting corresponds to a wedge of

approximately 1/16 height. Although, I have also heard people use

1/8 height per degree. In order to be accurate I have always found it best

to specify posting in terms of wedge height (1/16, 1/8, 3/16,...)

instead of degrees. If you have any questions please feel free to call us,



                   Seamus Kennedy, C. Ped

                   Hersco Orthotic Labs

                   (718) 391 0416



¡¦When I did my clinical rotation at Trinity in Lewisville with Greg Small, C.O., he gave me a

copy of a book that was extremely helpful. It was titled A Practical Manual

For A Basic Approach to Foot Biomechanics by Dr. Sheldon Langer, D.P.M. and

Dr. Justin Wernick, D.P.M. It does a really good job of addressing the

post vs. wedge issue with both forefoot and hindfoot. I don't know where a copy

of this book can be found but it isn't long so I could copy it for you if

you would like it. The way that I have understood the posting forefoot vs.

rearfoot is as follows:

       Evaluate the foot. If you have a forefoot that is in a

different plane that the rearfoot then a post can be used to reduce the deformity

caused by the compensation. That sounds confusing! If your forefoot

is 7 degrees inverted at subtalar neutral and your calcaneus is neutral then

upon weight bearing the forefoot will collapse and hyperpronate. Thus,

posting the forefoot 7 degrees will prevent the collapse and consequently

prevent hyperpronation. To do this, I would cast in subtalar neutral and

hopefully get the 7 degrees in the cast. Modify appropriately and then pull

polypropylene(etc.) with an extra strip of polypropylene over the

metatarsal heads. Afterwards, I would grind the extra material flat to achieve

the neutral rearfoot and 7 degree inverted forefoot. I hope this all made

sense and is what you were looking for. Good luck!!!!



Robbie

_________________________________________________________________________

 It's a good question, but I thinks it's beyond the scope to this list.There so much material to discuss I don't know how to begin. Good luck! David Lindsey, C.O.



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