I recently posted this message at Podiatry Arena
Asymmetrical foot pronation has the potential to create a LLD of up to 1cm (based on Bill Sanner's work), so obviously this will have consequences further up the chain (esp as the pronation is also associated with internal limb rotation).
What I am talking about is a foot pronately excessively as a compensation for a STRUCTURAL LLD - something that has crept into podiatric folklore over the years.... but its just another one of those myths (...'religious fanaticism' also comes to mind, but more on that later).I certainly do not see it clinically - I see feet pronate more on the long leg and I see feet pronate more on the short leg --- I just was not seeing the foot pronating with any increased frequency in the longer leg as I was taught and as I read frequently in the podiatric literature (...funny it does not appear in the orthopaedic or physiotherapy literature ). Invariably, when I did see a more pronated foot on the longer limb, its was often easy to find another reason for it (eg asymmetrical ankle joint ROM).
I used to get tired of students coming up to me in clinic when doing a gait analysis and saying things like "Craig, the left leg is longer, but I can't see it pronating more .... "maybe because it wasn't!!!" --- but thats what they got taught and read in the podiatric literature (they don't any more)
We did 3 studies:
1. Measured RCSP and navicular height between the short and long limb in those with a structural LLD --> there were no differences
2. A subsequent study used the FPI --> no differences
3. A Pedar in-shoe comparison --> there were some functional differences between the long and short limbs, but they were not related to any asymmetries in foot pronation.
As part of this, I also did an extensive literature review and it was not surprising that there was never any evidence to support this myth in the first place!!!!! (it is an interesting case study all this!!!!) ---- in fact the opposite was the case when viewing the literature!! (I will have to add the exact refs later when in office to get them).
The first was a study published quite some time ago that looked at 3D rearfoot kinematics and found no difference between the short and long limb in those with a structural LLD.
The other study is good case of .....(I better not say it ) --- it was published in JAPMA a long time ago, but the abstract, discussion and stated conclusion of this research was clear - that the foot does pronate more on the long side in those with a structural LLD .... BUT, BUT, BUT and very very very big BUT.... the paper looked at both functional and structural LLD and if you go thru the various tables in the publication (fortunately the paper listed the info on each subject) and extract just the data on those with a structural LLD (the tables mixed them all up) and then do a paired t-test (or wilcoxon) on the data, they actually showed the opposite!!! - ie there was no more pronated foot in the long or short limbs despite their claims ---> points to huge hole in peer review process prior to publication!!!
It just does not figure that the myth continues, when ALL the evidence says it does not happen.
We did try and publish our research, but you should have seen the reviewers comments from the journal --- they found nothing wrong with our methods and analysis etc, but spit a whole lot of vitriol with a recommendation to the editor that it not be published - the review was a two page rant paraphrased as "how dare they prove something wrong that every podiatrist knows is right".... they kept referring to all the evidence that supports the concept etc etc, but never mentioned what or where this evidence is. ..... I still have the manuscript (and the reviewers comments), but just have not yet bothered to rewrite it in a format for another journal yet.
The other amusing thing is, that a couple of years or so ago this topic came up in Barry Block's PM News (Kevin Kirby might remember this), so I posted a message re our research and the lack of evidence etc etc --- needless to say, it did not go down too well (at least I do remember Kevin supporting my observations) - I even got two private abusive emails saying something like "idiot" "moron" "how dare you" etc etc ---- guess which country and 3 letters after their names that these kinds of responses come from (I wish I kept them as it would be amusing to post them here now....) ..... 'religious fanaticisim' .....
....don't you just love this kind of stuff ?
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