Martin:
I would agree and add that the lateral valgus forefoot post is likely to cause
additional problems at a later date.
Martin Kidd wrote:
> Daryl, I find your clinical success interesting, and your supporting
> excerpts enlightening, but can't help thinking that the alteration of
> loading on different fibre bundles is the reason for your outcomes. This is
> akin to changing the alignment of a tyre on your car to remove pressure
> from one worn area, to place pressure on another area, which in turn, in
> time, will become worn. The body has a huge ability to compensate for
> changes, and your patient's feet will certainly appreciate the change. I
> hope, but doubt, that the reduction in pain will be permanent, unless the
> frontal plane deformities are addressed. I refer you to a chapter in "the
> Biomechanics of the Foot and Ankle", by Bob Donatelli, entitled
> "Biomechanical Orthotics", in particular .." supporting the forefoot
> abnormalities reduces the need for rearfoot compensation. For example,
> forefoot varus is compensated for by rearfoot subtalar joint pronation.
> Forefoot varus, by itself, is not destructive to the foot. However, at the
> subtalar joint compensatory pronation results in an "unlocking' of the
> foot, creating hypermobility and loss of a rigid lever from midstance
> through push-off. " Forefoot varus is addressed using a medial wedge on the
> forefoot. I have made up to 200 pairs of biomechanical orthotics over the
> last nine years, with excellent, although not infallible success at
> longterm pain reduction. Martin
> ----------
> > From: ashlini and daryl <[log in to unmask]>
> > To: [log in to unmask]
> > Subject: Re: taping for plantar fasciitis
> > Date: Tuesday, 21 March 2000 07:19
> >
> > Martin Kidd wrote:
> > >It follows that anything that causes excess pronation, such as a
> > > lateral forefoot post, would be detrimental to foot stability.
> > > Martin Kidd.
> >
> > I disagree. The wedging acts on the MTJ, not the STJ and aims to evert
> the
> > MTJ axis to prevent the dorsiflexion moment caused by XS pronation or
> > conversely by inducing a plantarflexory moment. Having now used these in
> a
> > clinical situation I find improved results from a treatment perspective
> with
> > valgus wedging at the forefoot. Following are few things that may help.
> >
> > *To quote someone far more intelligent than myself:
> > Eric Fuller has written,
> > "Arch flattening is caused by a plantar flexion moment on the forefoot
> or a
> > dorsiflexion moment on the forefoot. So, we need to analyze the foot and
> > figure out what structures could cause a plantarflexion moment on the
> > forefoot or a dorsiflexion moment at the rearfoot at the level of the
> MTJ.
> > (MTJ is an arbitrary divider of forefoot and rearfoot.) Tension in all
> the
> > slips of the plantar fascia, the plantar calcaneocuboid ligaments, the
> > spring ligament and a few muscles combined with compression at the joint
> > surfaces can prevent
> > dorsiflexion of the forefoot. There is redundancy, that is to say that
> the
> > load may or may not be shared across all of those structures. For
> example,
> > the medial slip of the plantar fascia may have 70% of the load and the
> > plantar calcaneo cuboid ligament may have 30% of the load in one
> situation.
> > A forefoot valgus wedge may cause a shift in the load from the medial
> slip
> > in the plantar fascia to the plantar calcaneo cuboid ligaments. The total
> > load remains essentially the same (body weight) but the structures that
> > support the load change. Less load in the medial slip of the plantar
> fascia
> > = less pain. I believe the 'locking the MTJ' (maximal eversion of the
> LMTJ)
> > puts more load in the lateral plantar ligaments."
> >
> > *Kogler GF, Solomonidis SE, Paul JP (1998)The influence of medial and
> > lateral wedges on the loading of the plantar aponeurosis. Proceedings
> from
> > the IXth World Congress of the International Society of Prosthetics and
> > Orthotics. Amsterdam: International Society of Prosthetics and
> Orthotics.
> > "......An in vitro method that simulated "static" stance was used to
> > determine the loading characteristics of the plantar aponeurosis. Nine
> test
> > conditions were evaluated with eight different wedge (6degrees)
> > combinations and a level plane serving as the control. Each of the
> forefoot
> > wedge treatment groups was statistically distinct compared to the neutral
> > control, with lateral forefoot wedges decreasing the strain in the
> plantar
> > aponeurosis and the medial forefoot wedges increasing strain (p<0.05).
> The
> > rearfoot wedge conditions that did not combine the use of a forefoot
> wedge
> > were not statistically different from the control (p.0.05)"
> >
> > *There was also a presentation at the Aust Pod Conference in 98 (and I
> think
> > a few subsequent times)comparing valgus forefoot wedges to meidal wedges,
> > FO, etc and it suggested that valgus wedging was the more effective.
> >
> > Hope this clarifies a few things,
> > Daryl
> >
> >
--
Douglas M. White, PT, OCS
Physical Therapist, Consultant
191 Blue Hills Parkway
Milton, MA USA 02186
P: 617.696.1974
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