Dear Ray,
I tend to think in terms of the lateral flange having two
posible jobs; nothing or something. In some cases the lateral flange may
have a role to play in retention of tissue and an influence to exert on the
rear foot...and you can obviously vary this with shape and dimensions of the
flange.(UCBL even) However if you view it from the Kev Kirby model it's
seems rare that you would want to add the pronatory GRF's to a foot that you
have decided has some form of excess pronation.
The DC wedge model suggests removal off "lateral orthotic reaction forces"
to enhance the ability to limit/effect/change/modify foot function...(or
even exert some control) over too much pronation.
Usually a meniscal kind of shape that tapers neatly into the side
wall of the heel cup of footwear seems innocuous enough.....you can still
use the cuboid notch concept if required. My past in playing around with
boots a lot leaves me feeling that in boots a lateral flange is usually
unncessary in lots of cases......mind you I am still very much the novice.
Your thoughts much appreciated.
Regards Phill Carter
-----Original Message-----
From: Ray Anthony <[log in to unmask]>
To: 'INTERNET:[log in to unmask] <[log in to unmask]>; 'Podiatry
Mailbase' <[log in to unmask]>
Date: Tuesday, 8 June 1999 22:29
Subject: RE: Heel cup shape
>
>Craig wrote:
>
>>Notty and Phil,
>I am interested in your comments regarding getting an accurate amount of
>lateral heel cup expansion on the positive cast. I use a simple slide
>caliper (i think that's what it is called) to measure posterior heel width
>while weight bearing. I am then able to use the same instrument to do the a
>similar measurement on the positive cast and therefore know whether to
>remove or add plaster. Since i have started this i have found a huge
>improvement in consistency of fit of my orthoses both to shoe and heel.
>- Craig Tanner,
>Alphington Sports Med.
>Victoria, Aus <
>
>Absolutely Craig!
>
>We do this for our customers at RX Laboratories. The podiatrist will
>caliper the weight-bearing width of the heel fat pad and chart this on
>their Rx form. We will apply a lateral expansion and use a caliper to get
>an more accurate heelcup width based on their measurement. Customers doing
>this are finding less lateral impingement problems with their orthoses.
>
>Careful though.....if the width of the heel seat of the shoe is not taken
>into consideration, this method can often lead to devices with heel cups
>that are simply too wide for the heel counter of the shoe. Remember that
>patients can (and often do) squash their wide heels into narrower heel
>counters, but a rigid orthosis shell can't do this!
>
>
>Ray Anthony
>RX Laboratories, UK
>
>----------
>> From: P & E Carter <[log in to unmask]>
>> To: [log in to unmask]
>> Subject: Re: Heel cup shape
>> Date: Tuesday, 8 June 1999 3:00
>>
>> Dear Notty,
>> I like to imagine you climbing down off a soap box
>after
>> one of those "rants"........thankyou and .....interesting. Out here one
>lab
>> solves the problem of how much lateral addition by leaving it off and
>having
>> no lateral flange......obviously limits degree of inversion in relation
>to
>> stabliity and types of footwear used etc. Please don't give yourself an
>> ulcer over breakfast......all that thought so early....
>>
>> One thing we did in the ski trade was use heated birko cork compound in
>a
>> plastic shell with a cover to protect feet and position foot as desired
>> then turn on suction in vacuum bag over foot in order to get cast. Some
>> times just unweighted neutral some times partial weighted cast depending
>on
>> the feelings of the "artiste"at the time. Some interesting possibilities
>> there maybe...I wonder if that has ever been persued by some one with
>> the right knowledge?
>> Regards Phill Carter
>> -----Original Message-----
>> From: Notty Bumbo <[log in to unmask]>
>> To: [log in to unmask] <[log in to unmask]>
>> Date: Tuesday, 8 June 1999 1:46
>> Subject: Re: Heel cup shape
>>
>>
>> >Ah, you invite me to commit heresy. So, what the hell, no one takes me
>that
>> >seriously anyway.
>> >
>> >You are right, the idea that I am trying to develop is quite different
>from
>> the
>> >tri-axial idea. For one thing, its not as articulate....
>> >
>> >As for tri-axial, or Blake inverted, or medial skive, (no offense
>intended
>> here,
>> >everyone) I am of the opinion that these are really just three ways to
>> arrive at
>> >the same conclusion - to gain greater control of the rearfoot position
>> without
>> >the foot being present in the laboratory. Consider: if the patient could
>> >tolerate the time involved and the heat, and could provide optimum
>> feedback, you
>> >could just mold the materials directly to their feet while manipulating
>> their
>> >foot position according to the physician's specific approach. This would
>> >eliminate the approximations required for soft tissue expansions, permit
>> >accurate rearfoot, midfoot and forefoot positioning, and the need for an
>> invoice
>> >from the lab! Now, there's an advance in orthotic therapy!
>> >
>> >The fact is, we need to use rigid materials heated to hundreds of
>degrees,
>> and
>> >formed over even more rigid shapes that resist the temperature of the
>> heated
>> >materials so that those materials can cool and set in the determined
>shape.
>> That
>> >material then needs to maintain its shape and resist extreme forces
>during
>> use.
>> >
>> >During the course of biomechanics practices over many decades, it is
>> observed
>> >that some feet respond to the "standard" neutral position orthoses,
>whereas
>> >others do not. Blake astutely realized that, due to soft tissue
>interposed
>> >between the osseous structures and the orthoses, it might work better to
>> >"over-do" the correction, reasoning that such an increase in control
>> parameters
>> >might actually bring these particular feet to something approaching
>> calcaneal
>> >vertical (I don't really care what theory is practiced or "believed",
>I'm
>> just
>> >looking at the issue here). Lundeen and Kirby, bless their hearts, came
>to
>> a
>> >similar conclusion. They both looked at the problem, and as human nature
>> would
>> >have it, they both arrived at unique yet similar approaches to solve the
>> >mechanical aspects of this problem, which of course was different from,
>but
>> >similar to, the one developed by Blake.
>> >
>> >Now, the interesting thing is that the medial skive is easier to apply
>than
>> >Blake's or Lundeen's approach. Despite that, all three have one inherent
>> problem
>> >(well, actually, two, but more on that later). When you invert the heel
>of
>> a
>> >plaster cast, which is rigid, two things occur that do NOT occur in the
>> actual
>> >foot. One - the width profile of the heel of the cast, viewed
>posteriorly,
>> >becomes narrower. This even occurs with the medial skive technique, as
>we
>> are
>> >removing volume from the medial aspect of the cast. Now, by rendering
>the
>> cast
>> >narrower, we need to account for that width loss with an increase in
>> lateral
>> >expansion plaster - more than we would usually add. The problem comes
>with
>> >knowing how much more to add. It is nearly impossible to arrive at a
>> formula,
>> >because there are several factors which can interfere with a formula -
>the
>> >actual width to length ratio of the foot; the plantar curvature (some
>casts
>> >capture a more flattened plantar heel contour, others more rounded; some
>> feet
>> >demonstrate little change in the contours from the heel into the medial
>> arch,
>> >say a severe pes planus foot type); the actual accuracy of the cast
>> relative to
>> >the foot.
>> >
>> >Two - when you invert the cast, regardless of the method employed, you
>are
>> in
>> >essence raising the medial aspect of the foot. Now, the foot, while
>> flexible,
>> >displays the standard response to physical force that any overtly solid
>> object
>> >displays - it moves in the opposite direction. Pretty basic (yeah, I
>know,
>> there
>> >are more scientific ways to explain this, but its not even 7 in the AM
>> right
>> >now, and I figure if someone doesn't get what I'm saying here, well, go
>> have
>> >breakfast). The problem is that, when I move an object that has
>rotational
>> >properties around an axis - it rolls! So if I lift the medial side of
>the
>> foot,
>> >it stands to reason that the lateral side of the foot must - drop! Well,
>so
>> >what, you might ask? (Some have actually said that). If the lateral side
>> drops
>> >in relationship to the medial aspect being lifted, but we don't permit
>the
>> >lateral side to respond to this action on the part of the orthoses, it
>will
>> >resist the efforts being applied to the medial side. So both the width
>of
>> the
>> >heel cup and the shape of the heel cup are problematic (I have spoken to
>> both
>> >Kevin and Richard Blake about these observations several times, though
>not
>> to
>> >Dr. Lundeen - it would be interesting to hear their comments on this
>> factor).
>> >
>> >Earlier in this diatribe I mentioned there were two issues. The second
>> issue is
>> >reproducibility. Most orthoses, produced digitally or in the traditional
>> plaster
>> >approach, suffer from the "art vs. science" problem as much as overall
>> >biomechanics does. What one technician does is seldom what another
>> technician
>> >does. This is lessening somewhat with the new CAD-CAM systems,
>especially
>> the
>> >Sharp Shape system, as the measurement parameters are captured
>accurately,
>> >something that is very difficult and time consuming to do with plaster
>> >casts/molds. However, there is still room for operator bias, there is
>still
>> the
>> >overarching problem of "what you see is what you get" - what the doctor
>> sends
>> >the lab is what the lab has to go with, and nothing more; and there is
>> still
>> >little agreement from lab to lab or from practitioner to practitioner on
>> theory,
>> >technique, etc.
>> >
>> >All this makes it very difficult to say that one technique is better
>than
>> >another technique. For my money, I'd say use the old US Marine's
>> battlefield
>> >slogan, modified for the podiatric profession, to whit:
>> >
>> > "Amputate 'em all, and let the HMO's sort 'em out".
>> >
>> >Let the howls begin.
>> >
>> >Notty
>> >
>> >P & E Carter wrote:
>> >
>> >> Dear Notty,
>> >> Re your whimsical sense of humour Re The cAP
>key...I
>> >> really got a laugh. In relation to the articulated orthosis your last
>> >> suggestion brings to mind the polyaxial ideas....Lundeen? about 1988?
>> ...I
>> >> tried that recipe and following the destructions I got things that
>look
>> very
>> >> like a Blake style inverted...these don't articulate of course. What
>do
>> you
>> >> think?
>> >> Regards PhillCarter
>> >> -----Original Message-----
>> >> From: Notty Bumbo <[log in to unmask]>
>> >> To: [log in to unmask] <[log in to unmask]>
>> >> Date: Sunday, 6 June 1999 2:34
>> >> Subject: Re: Heel cup shape
>> >>
>> >> >The use of EVA foams in this regard will promote increased material
>> >> compression
>> >> >but not functional articulation. That is, unless the "board" below
>the
>> EVA
>> >> has
>> >> >both rigidity and can be segmented at the same time. Think in terms
>of a
>> >> >"jointed" orthoses. The first "joint" would be placed at the
>mid-tarsal
>> >> >articulation; the second to permit articulation of the first ray.
>Thus,
>> you
>> >> >would have three distinct segments to the plate. Now, prevent each
>> "joint"
>> >> from
>> >> >deforming beyond a specified degree of movement within or through the
>> >> various
>> >> >planes, i.e., control the articulations in relationship to the degree
>of
>> >> >influence you desire to excersize on the specific foot. And, Voila!
>> >> >
>> >> >This is fun!
>> >> >NB
>> >> >
>> >> >P & E Carter wrote:
>> >> >
>> >> >> Dear Notty,
>> >> >> I'm sure your ideas go well beyond my lay and
>> >> >> inexperienced efforts but what about mounting three dimensional
>pieces
>> of
>> >> >> varying density EVA foams shaped to fit and influence the foot in
>> >> question
>> >> >> in the ways deemed suitable. Mount these pieces on a flexible piece
>of
>> >> thin
>> >> >> 'board' and you have an orthosis that will articulate with the
>> >> >> foot.......done that and trying to improve and make more sense of
>the
>> >> >> concept.....your ideas gratefully accepted
>> >> >> Regards Phill Carter
>> >> >> -----Original Message-----
>> >> >> From: Notty Bumbo <[log in to unmask]>
>> >> >> To: [log in to unmask] <[log in to unmask]>
>> >> >> Date: Friday, 4 June 1999 11:13
>> >> >> Subject: Re: Heel cup shape
>> >> >>
>> >> >> >I think you misunderstand my posts on this topic. I am not against
>> rigid
>> >> >> >materials for orthoses - in fact, such materials are critical to
>> >> >> contributing
>> >> >> >significant influence on foot mechanics. What I am trying to get
>to
>> in
>> >> this
>> >> >> >discussion is something there is still little language for, so
>here's
>> >> >> another
>> >> >> >try.
>> >> >> >
>> >> >> >The problem is not longitudinal rigidity, it is the lack of
>> articulation
>> >> >> >congruent with joint articulation. This is NOT the same thing as
>> using
>> >> >> flexible
>> >> >> >materials, because with flexibility comes a significant reduction
>in
>> >> >> functional,
>> >> >> >dynamic influence (note that I use this word rather than
>"control").
>> One
>> >> >> example
>> >> >> >is the difference between an AFO that has an ankle joint, and one
>> that
>> >> does
>> >> >> not.
>> >> >> >Both provide some control and some stability, but the one with the
>> ankle
>> >> >> joint
>> >> >> >respects the articulation of the ankle joint itself to provide for
>> near
>> >> >> normal
>> >> >> >function while providing functional assistance and improvement.
>> >> >> >
>> >> >> >To apply a similar idea to foot orthoses requires some
>imagination,
>> and
>> >> >> >unfortunately, technology that does not as yet exist.
>> >> >> >
>> >> >> >Hopefully, this gets closer to the idea that I am trying to
>convey.
>> >> >> >
>> >> >> >If not, have a scotch, and give it no further thought.
>> >> >> >
>> >> >> >NB
>> >> >> >
>> >> >> >[log in to unmask] wrote:
>> >> >> >
>> >> >> >> NB
>> >> >> >> I agree with you when you question the use of rigid materiels in
>> the
>> >> >> >> construction of othoses. Not being an expert in thoeretical
>> >> biomechanics
>> >> >> I
>> >> >> >> have formed the view that the foot must be influenced in a
>dynamic
>> way
>> >> >> using
>> >> >> >> posting which will attempt to re-allign the foot. The materiel
>used
>> to
>> >> >> form
>> >> >> >> the shell should as a rule be flexible - its function being to
>> >> >> accommodate
>> >> >> >> the posts and allow the foot to retain a measure of its inherent
>> >> >> function.
>> >> >> >> I would go on but I'm off for a spin in my old VW beetle,
>> >> >> >> Cheers
>> >> >> >> Mike Black
>
>
>
>
>----------------------- Internet Header --------------------------------
>Sender: [log in to unmask]
>Received: from mailout2.mailbase.ac.uk (mailout2.mailbase.ac.uk
>[128.240.226.12])
> by hpamgaab.compuserve.com (8.8.8/8.8.8/HP-1.4) with ESMTP id
>HAA11030;
> Tue, 8 Jun 1999 07:14:06 -0400 (EDT)
>Received: from naga.mailbase.ac.uk (naga.mailbase.ac.uk [128.240.226.3])
> by mailout2.mailbase.ac.uk (8.9.1a/8.9.1) with ESMTP id MAA08524;
> Tue, 8 Jun 1999 12:13:29 +0100 (BST)
>Received: (from daemon@localhost)
> by naga.mailbase.ac.uk (8.8.x/Mailbase) id MAA16992;
> Tue, 8 Jun 1999 12:11:59 +0100 (BST)
>Received: from teapot25.domain0.bigpond.com (teapot25.domain0.bigpond.com
>[139.134.5.173])
> by naga.mailbase.ac.uk (8.8.x/Mailbase) with SMTP id MAA16980;
> Tue, 8 Jun 1999 12:11:51 +0100 (BST)
>Received: from localhost (localhost [127.0.0.1]) by
>teapot25.domain0.bigpond.com (NTMail 3.02.13) with ESMTP id ka197454 for
><[log in to unmask]>; Tue, 8 Jun 1999 21:09:55 +0900
>Received: from EXIP-T-006-p-208-108.tmns.net.au ([139.134.208.108]) by
>mail0.bigpond.com (Claudes-Technicolor-MailRouter V2.3a 13/134909); 08 Jun
>1999 21:09:53
>Reply-To: <[log in to unmask]>
>Date: Tue, 8 Jun 1999 21:05:07 -0700
>X-MSMail-Priority: Normal
>X-Priority: 3
>X-Mailer: Microsoft Internet Mail 4.70.1157
>MIME-Version: 1.0
>Content-Type: text/plain; charset=ISO-8859-1
>Content-Transfer-Encoding: 7bit
>Message-Id: <[log in to unmask]>
>Subject: Re: Heel cup shape
>From: "Craig Michael Tanner" <[log in to unmask]>
>To: <[log in to unmask]>
>X-List: [log in to unmask]
>X-Unsub: To leave, send text 'leave podiatry' to [log in to unmask]
>X-List-Unsubscribe: <mailto:[log in to unmask]>
>Sender: [log in to unmask]
>Errors-To: [log in to unmask]
>Precedence: list
>Content-Transfer-Encoding: 7bit
>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
