Clinical Biomechanical Evaluation of the foot

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With all the controversy regarding what biomechanical clinical exam of the foot . Root , tissue tension,SALRE , FPI , etc . , is there a general consensus in what clinicians are using as part of that static biomechanical exam of the foot. I’ve always felt that I always got valuable information from using the Root Theory in my practice , however with the onslaught of literature that been published, questioning the validity of its measurements , It seems that any of these theories vary in their reliability and validity , making many clinicians wary about what evaluation techniques to use in their practices. Maybe it should boil down to what process seems to get the best result when prescribing orthotics

 

I don't believe we should have a theory as such. My physiotherapy colleagues do not have a theory of shoulder function for example. They just understand the biomechanics, the potential pathology and their best management based in the evidence available.
I view physical stress/tissue stress theory to be a correct observation of the mechanism of injury rather than a 'theory'. If a tissue has to deal with forces in excess of its fatigue capacity, injury ensues. That is verifiably true if you hit yourself with a hammer. Simply with biomechanics we are looking at smaller repetitive/prolonged forces.
Again, SALRE, I don't really view as a theory but a elucidated description of how the anatomy of the rearfoot dictates the magnitudes of loads within different tissues. Using root theory you could make an orthoses which makes the plaster cast of the foot assume a perfect 90 degree bisection. You could then put the actual foot on the orthotic and any number of observations could result. SALRE explains why this is the case.
There is obviously more going on in the foot than the STJ but a combination of SALRE & tissue stress creates the correct thought process to manage pathology.
I have recently read a good amount around the subject and at the end of it I come back to the example I started of with RE: physiotherapists. I think we have a duty to read as broadly as possible to gauge the best understanding of the biomechanics and mechanism of injury so we can then rationalise an intervention.
The most complete and helpful paper I have read to date is this; https://www.researchgate.net/public...nical_therapy_of_the_foot_and_lower_extremity
The issue with Root theory as a basis for the whole basis for the assessment was that I found when the intervention didn't work I was up shit creek without a paddle. Also, it took a long time and I was never really too sure why I was gathering the information I was doing

 

Those of us who use it, like to call it tissue stress, not tissue tension (and bone is a tissue. I've heard it erroneously called soft tissue stress.) The point of the biomechanical exam is to inform what modifications you make to your orthotic prescription. One criticism of the Root paradigm is that for the vast majority of feet you do the exact same thing: Take an neutral position cast and balance to vertical That will work a certain percentage of the time. When it doesn't work you have to look for the mistake that you made with no direction as to what that mistake was.

On the other hand with tissue stress, you identify the injured structure and design an orthosis to reduce load on the injured structure. Take peroneal tendonitis in a foot with a laterally deviated STJ axis. The ground is tending to cause supination in this foot and the peroneal muscles have to work harder than average to resist the inversion tendency. In tissue stress, for this foot, you would want to increase the pronation moment from the ground. If the orthotic was not successful in reducing symptoms you could increase the valgus wedge or find some other way of increasing pronation moment. Also, under neutral position paradigm it is very unlikely that someone would intend to increase pronation moment from the ground. However, if a neutral position disciple happened to find a forefoot valgus and they balanced the cast to perpendicular they might, unintentionally, increase pronation moment from the ground.

 

I surmise by your response that you hone in on tissue stress and SALRE, so if that is your emphasis in your Biomechanical eval are you then documenting whether the STJ axis is medically or laterally deviated and is so by how much , to support your rationale for using SALRE as part of your orthotic prescription. ? Are you also documenting , the results of the Supination Resistance Test and or results of MMT and pain on resistance or areas of painful palpating of bony structures to support your rationale for what orthotic prescription you will use? Do you not use any Root measurements in your evaluation such as RCSP or NCSP / FF to RF measurements. ? Do you ever incorporate the FFI into your documentation as part of your eval?It would seem to me we almost need an algorithm which includes multiple tests and or measurements to make our decision .Then again , with all the tests and measurements we take in the static position , how much do the measurements carry over during dynamic conditions anyway? , but then again we have to have some reference and startingpoint for our evaluation, correct?

 

Yes, I document STJ axis position by categorizing. Extreme lateral, lateral, average, medial extreme medial. I don't use the supination resistance test. MMT?
I do document location of pain to palpation and pain with muscle testing. I wrote an article about what I do for podiatry today. https://www.hmpgloballearningnetwork.com/site/podiatry/issue/7493

I don't use any Root measurements in the exam. I do use maximum eversion height and have described that here on podiatry arena. FFI?

I believe that you do not need a reference starting point. That is one of the problems with Root/ neutral position measurements is that you are comparing to a "normal". I disagree with what Root et al think is normal. I think a better approach is to look at the foot that is in front of you and figure out how you can alter the forces applied to it so that it can function better with less pain.

 

Most of my current opinions around biomechanical foot assessment are informed by reading people like Eric and others so I can't really improve on anything he has already said.

I would add as a general note that when treating athletes and (generally) healthy populations I always like to consider hip and core strength & function. I like a posterior chain activation test and give out glute programs to all who need them, which are most people in my experience. Very few people can achieve hip extension in prone without their hamstrings/lumbar joining in and this is a movement I like to drill often with activation, then strength, then endurance within that strength goal. People often obsess about 'calf tightness', when in my experience most people can't adequately extend their hips enough during gait for this to be of a large concern anyway. I find that strengthening hip extension muscle patterns translates to better ankle mobility because they start walking with greater hip extension and body weight, GRF and repetition takes care of the rest. Also, like the analogy of a bow string with forces acting across a joint. I have found that 'tight hip flexors' are almost exclusively weak hip extensors. The powerful muscles win the race. Instead of stretching out strengths it is better to strengthen our weaknesses and nothing relaxes tight hip flexors like stronger glutes.

I also like the work of spinal expert Stu McGill. He found (and evidenced) that the ability to stabilise the lumbar region with 'core' musculature translated to greater control and power capacity at the hip. He uses the term, "proximal stability unleashes distal ability", but I prefer the S&C term, "you can't fire a cannon off of a canoe". I like most people to be able to demonstrate hip control I'm extension/ext rot and abduction and be able to do a solid rolling plank for a couple of minutes at a clip. I have found Orthotic therapy to be pretty remarkable at reducing & eliminating pain but I am a big believer in taking care of the whole chain, otherwise the foot is a engineering marvel at the end of a very loose and heavy chain.

 

"Then again , with all the tests and measurements we take in the static position , how much do the measurements carry over during dynamic conditions anyway?"

In the following paper;

Challenging the foundations of the clinical model of foot function: further evidence that the root model assessments fail to appropriately classify foot function Hannah L. Jarvis1,2*, Christopher J. Nester1 , Peter D. Bowden1 and Richard K. Jones1 -

The conclusion was -
'None of the static examinations advocated by Root et al and investigated in this study led to identification of foot deformities that were related to altered foot kinematics. These examinations are routinely used in clinical practice, but the results from this study and allied literature provide little support for their continued use. As such, we believe the Root et al' description of foot function and the associated assessment protocol are not a sound basis for clinical evaluation of the foot nor orthotic prescription'

Stick a fork in root theory. He was a trail blazer but were 60 years on

 

I have a very simplistic, uncomplicated rule that I follow in my paradigm of therapy:

Reduce gravity drive pronation, strive towards hip drive pronation
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How you do it, that is your choice.

​

 

Your response makes sense, I think what is confusing and or frustrating about the orthotic industry is that we clinicians understand that approximately 80 % or greater of the time ,custom orthotics are successful in improving function and relieving symptoms in our patients , so feel these patients in may not be as critical to understand which evaluative method was effective in determining what orthotic material and prescription to use along with other treatment methods that were concurrently implemented in the treatment plan. I believe it’s the 20 % or so cases that aren’t totally successful that require more understanding as to what evaluative processes were needed in order to achieve 100% success in achieving pain free function. With the cost of custom devices being what they are and adjustment costs incurred by either the practitioner or more importantly, the patient, I believe it it still important to continue to strive to achieve a gold standard in our evaluation process both statically and dynamically in order to achieve closer to 100% success in the treatment of our patients.

 

Which 20% of pathologies are you failing to resolve? If you read the paper I linked you it details the underlying biomechanics and best treatment for most pathologies we're likely to stumble across

 

Could you re send the link for the article your referring to , thanks, Steve

 

https://www.researchgate.net/public...nical_therapy_of_the_foot_and_lower_extremity

 

After reading that chapter, if I was a young Podiatrist, I think I would stick to surgery and forget biomechanics!

In actuality, orthotic therapy is just not that complicated. Although, after reading that chapter, one would probably argue against that.

Steve, do as I suggest. Keep it simple. Attenuate the gravity drive pronation and the musculoskeletal symptoms will dramatically improve.

 

We've had this discussion before.
https://podiatryarena.com/index.php?threads/occams-razon-or-the-law-of-parsimony.113264/page-6

In that thread Brian criticized the use of physics in biomechanics because it was too complicated.

In reference to gravity drive and hip drive pronation I wrote, in that thread.

Brian, you are coining a term that should use physics to explain what it is. Yet, in this thread you were critical of the over complication of biomechanics with the use of the terms force and moments. Brian you have introduced the term gravity drive pronation without a way of understanding what the term means. If you cannot define gravity drive pronation in terms of forces and moments there is no reason for you, or others, to use the concept.


If you want to know more you can search Brian Rothbart here on arena. Or search Brian Rothbart charlatan.

 

eFuller,

How can anyone take what you say seriously when you demonstrate an ineptitude in following the posting rules governing this forum.

Just food for thought.

 

Brian, Calling me inept is a personal attack that is breaking the rules of the forum.
If you wanted to point out a personal attack, you would quote what was said and say that is a personal attack.

Back to academics. If one claims that there is such a thing as hip drive pronation they should be able to explain, with physics how the hip causes pronation.

 

No attack, simply stating the fact that you continuously disregard the forum rules.

Now, if I called you a charlatan, that would be a personal attack.

 

Hey Eric.
Is there any way to access the 'Subtalar Joint Equilibrium and Tissue Stress Approach' complete paper. The copy I have have I got off of Dr Kirby' Research Gate page. Is there a more complete version.
Cheers.