Podiatry related medical myths - Busted?

It means that there have been 3 studies that have looked at differences between rearfoot pronation/calcaneal eversion (whatever you want to call it) on the long and short leg in those with a structural leg length difference and none of them found that there was more pronation in the long leg compared to the short one.

 

In PT dysfunction there is often additional abduction of the forefoot on the rearfoot. Anecdotal observation. If there is no change in the shape of the articular facets of the talus and the calcaneus then the location of the axis relative to these two bones won't change. However, additional forefoot abduction will move the forefoot relative to the axis and make it appear more medially positioned to the forefoot.

Does anyone have x rays of a patient pre and post posterior tibial dysfunction showing additional forefoot abduction. That would be an easy paper.

Eric

 

Another myth: A rearfoot post with a 4 degree bevel on the underside will cause the STJ to move only four degrees. The only evidence have or this is the impression in my shoe that matches the underside of my rearfoot post.

Eric

 

It means that there have been 3 studies that have looked at differences between rearfoot pronation/calcaneal eversion (whatever you want to call it) on the long and short leg in those with a structural leg length difference and none of them found that there was more pronation in the long leg compared to the short one.

Thanks Craig. Any chance of the references for them (or better still the PDF!!!)
Cheer
JB

 

Posting PDF's is problematice because of copyright issues:

 

Gday Eric, thanks. I wonder if any podiatrist of extended vintage has noticed a change in orientation of the axis?

 

I guess I am about as "extended in vintage" as they come here on Podiatry Arena....especially when it comes to STJ axis spatial location measurement.

I have seen both improvements in STJ axis location, from more medial to more normal, and worsening of STJ axis location, from more normal to more medial, in my patients over the past 25 years of measuring STJ axis location. Actually, this would be an excellent longitudinal study if we had a more accurate way to measure the spatial location of the STJ axis and did this over a number of years.

Like Eric said, posterior tibial tendon dysfunction definitely will cause an increase in medial devation of the STJ axis. Lisfranc's fx-dislocation injuries also cause an increase in STJ medial deviation.

 

Interesting point Kevin. Do you then treat the tib post dysfunction or lisfranc dislocation directly (both anatomical structures in the midfoot if taking tib post insertion as important in the condition) - I would imagine that with orthotic therapy the bend in the plastic would be concentrated towards the midfoot, if tissue stress theory is taken into account. Alternatively, does a medial heel skive exert control via the rearfoot which in turn stabilizes the injured midfoot?

 

I do not knock any of what you say, except to ask a few pertinent questions. 1) You talk about a medially deviated ST axis: how do you assess this, measure it, confirm it? 2) How do you know that the treatments you are offering "the safest and best medical treatments available": how do you know that they are not dangerous? That is all we ever asked................ 3) Last time I looked at the evidence, it seemed that over the counter worked as well as bespoke - if I am wrong with modern evidence telling us otherwise, correct me and I will apologise and back down.

 

By palpation of the plantar foot, noting the quality of rotational motion of the foot relative to the leg during open kinetic chain exam, assessing the points of least rotation at the anterior and posterior exit points of the STJ, and by assessing talar head position during standing.

Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987.

Morris JL, Jones LJ: New techniques to establish the subtalar joint's functional axis. Clinics Pod Med Surg., 11(2):301-309, 1994.

Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001.

Piazza SJ: Mechanics of the subtalar joint and its function during walking. Foot Ankle Clin N Am, 10:425-442, 2005.

Lewis GS, Kirby KA, Piazza SJ: A motion-based method for location of the subtalar joint axis assessed in cadaver specimens. Presented at 10th Anniversary Meeting of Gait and Clinical Movement Analysis Society in Portland, Oregon. April 7, 2005.

Spooner SK, Kirby KA: The subtalar joint axis locator: A preliminary report. JAPMA, 96:212-219, 2006.

Lewis GS, Kirby KA, Piazza SJ: Determination of subtalar joint axis location by restriction of talocrural joint motion. Gait and Posture. 25:63-69, 2007.

Lewis GS, Cohen TL, Seisler AR, Kirby KA, Sheehan FT, Piazza SJ: In vivo tests of an improved method for functional location of the subtalar joint axis. J Biomechanics, 42:146-151, 2009.

I've treated over 2,000 children's flatfeet over the past 25+ years with custom foot orthoses. I have never, even once, seen harm or heard from another source that I caused harm to the child from these devices. I also was trained by experienced podiatrists such as John Weed, Ron Valmassy, Chris Smith, and Richard Blake who together have also treated thousands of children with custom foot orthoses and have never noted any "dangerous" effects, only grateful parents from these same children. I have been positively rewarded over the years of having many parents come back to me and state how they are so grateful that I was the one physician that had enough knowledge and expertise to allow their children to run and play with less pain and difficulty since their other physicians told them that "flatfeet are normal, they will grow out of it and their growing pains" and told them there was nothing they could do about it.

Who is the most ethical physican in this case, Rob? The physician that tells the child's parents that "flatfeet are normal, they will grow out of it and will grow out of their growing pains" since this seems to be the prevailing "medical evidence"? Or would the most ethical physician rather be the one that uses their skill and knowledge in the clinical application of foot and lower extremity biomechanics to design a custom foot orthosis for that child that improves their foot function, but does not have "medical evidence" to support their earnest attempts to provide the child with improved weightbearing function and more comfort when performing these weightbearing activities?

There, unfortunately, is a lack of studies that have looked at children's flatfeet using these criteria so my opinions are solely based on my own clinical observations, theoretical assumptions and the clinical opinions of other experienced clinicians. Clinically, however, if improved gait function and improved symptoms can be considered as the most meaningful goal in treating children's flatfoot deformities, I can very clearly state that from my observations and experience in treating thousands of these children that the well-made custom foot orthosis is much more likely to produce a significant improvement in gait function and a reduction of symptoms than will over-the-counter foot orthoses.

Thanks Rob for a great discussion.:drinks

 

Rod:

You don't need "bent plastic" to treat these conditions. You can use "bent steel", "bent cork and leather", "bent adhesive felt" or "bent cardboard" or any other material for that matter, that can resist deformation from the forces exerted from the plantar foot inside the shoe.

Seriously, I have written and lectured extensively on posterior tibial tendon dysfunction and its treatment with custom foot orthoses (Kirby KA: Foot and Lower Extremity Biomechanics II: Precision Intricast Newsletters, 1997-2002. Precision Intricast, Inc., Payson, AZ, 2002, pp. 97-106). I have also attached the pdf of the paper I wrote a decade ago on this subject (Kirby KA: Conservative treatment of posterior tibial dysfunction. Podiatry Management, 19:73-82, 2000).

LisFrank's fracture-dislocation patients generally have problems with midfoot pain and also may have pronation related symptoms due to the lateral shift of the forefoot relative to the rearfoot and STJ axis that often occurs with these injuries. Specially designed custom foot orthoses are invaluable at treating these patients also.

 

He, he, he - many thanks Kevin! This has turned into a good thread, reading as the big boys go at it... Keep it coming says I.

 

JB,

I've emailed them to you

IG