Past, present and future of "podiatric" biomechanics

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Hi all,
I am a level 2 student of podiatry, after reading four weeks of biomechanical reviews, journals and books, I am so confused "Rootian' podiatric biomechanics supposedly is an outdated theory which was based on minimal scientific evidence. A more likel theory of biomechanical dysfunction is.......
so many theories, and equal amount of arguments over whose model is the most realistic. I am drowning in this sea of confusion.

 

It is your job as student to be confused --- it my job as a teacher to confuse you .... thats what makes teaching bimechanics such an exciting subject .... there is no right answer or right theory (though our knowledge and understanding has improved dramaticly in the last few years) ... it when YOU can reconcile the theoretical differences n different clinical contexts is wen you become a good critical thinking clinician with good clinical reasoning skills.

See:
CB Payne and AR Bird
Teaching clinical biomechanics in the context of uncertainty
J Am Podiatr Med Assoc 1999 89: 525-530

I would reply more fully, but Vancouver beckons....

 

Iaslam

For me feet are a bit like life. There is only one biological purpose for life and that is to reproduce and maintain the species and there is only one purpose for feet, to make bipedal ambulation relatively easy across many and various terrains. (and to stop your legs from fraying.) The way we live our lives are as varied as there are individuals but each individual has his own system that they use to get them from day to day. There is no correct way to live ones life (although some would have you believe that theirs is the only correct way). The same with feet, there is no correct way to walk, (ditto). We walk in the way that suits us best. But when we find that we cannot walk in a way that suits us and so causes us pain we turn to someone to fix our feet. This person must have some system that identifies and enables him as capable of doing that (may be he uses the Rootian system). In life maybe sometimes we walk a path that no longer suit us, it causes us pain and grief and we may turn to someone to help us change the path of our life. That person may have a system that you can identify ie he may be a catholic priest or a Seikh Guru or a paegan believer whatever, they will have their system and it is quite possible that, for most people, following any of those pathways will change their life system be benificial to them. Podiatry unlike faith has evolved over a few decades not millennia so systems are new and evolving and I believe that the astute practitioner takes something from all of these systems and over the years develops his own system and techniques for treating his patients feet. Whatever we do in life we need a system to work to sometimes we get to a point where we outgrow that system and evolve it or change to a new one but that doesn't mean the first one was invalid. It had the power to take us to a new place and a new direction which we would not have found without it. This is podiatry, science, life each new theory and system helps us on the way to the ultimate truth (if it exists) which we all may strive for but ironically never really want to reach because its the journey there thats so interesting.

On a more practicle level there are many systems but they generally have threads which connect them all. Rootian theory is basically a theory of position. Position and the change of position is the way we as humans can visualise the effects of moments and forces,even though sometimes we need no perceptible positional change to cause pathology, ie equilibrium theory, moments and forces affect tissue trauma, = tissue stress theory. Saggital plane progression looks at ways of making forward motion more efficient by 'normalising' / optimising all of the above, the same with Centre of Pressure Progression. You see they are all different, but at the same time symbiotic, systems with the single purpose of getting you to walk correctly ie pain free.

You know that sign on a box of cornflakes that says the contents may have settled during transport (so they now don't fill the box) Well at the moment your in transport and being shaken up and confused but eventually you will settle into a more ordered pattern and everything will become clear. (for a few weeks then someone will shake you into a new bowl)

Just an opinion, hope its not to deep for you, Cheers Dave Smith

 

As a student would you rather be taught by someone who was really sure that they were right and that there was only one right way to do somehting or would you like to be exposed to a debate on different theories. Remember, the guy who thinks he is right may not be.

When I was a student, many variations on Root biomechanics were taught. There was a general sense in my fellow students that there must be something there, but I don't quite undersand what they are saying. I think the problem was more with the theory than with the students. I am greatful that Kevin Kirby started writing about that time.

Some thougths on learning biomechanics.
You have to know your @!#$ anatomy (J. Morris)
Any theory should be be able to be summarized in a paragraph. eg Mechanical pain is caused by excessive stress to anatomical structures and mechanical pain is reduced by reducing the stress on that structure.
Know the assumptions that are presumed in the theory. eg Neutral position is stable. Often the assumptions are not explicitly stated. Sometimes they are. eg. Symmetry in gait will reduce pain. Question the assumptions.
Just because spilled glue on a patient's orthosis and the patient's pain went away does not mean that you should spill glue on all orthoses. A lot of pain is cured by the tincture of time. Your intervention should work mutiple times in similar situations.
Pick a theory that guides you in your decision making.
Read and think

Good Luck, and keep at it.

Eric

 

Have heart, keep the faith, and remember that without biomechanic's great founder you wouldn't be able to say to a patient "I think I can fix your problem with a Root".

cheers,

Felicity

 

In my view, the better practitioners get the simple basics right more often. The better practitioners know when something is not working sooner; and hence change direction. The better practitioners know when something is out of their sphere-of-influence and hence refer to another podiatrist or paramedical practitioner or specialist.


Despite Root's theory being "outdated", I still can't work out what the hell is wrong with it? These devices can still planar-flex the first ray; they can still provide a supination force medial to most STJ axes; they can still unload the plantar fascia; additions can be added to change increase or reduce 'forces'.

IMO, clear your mind, start simply; sharpen your clinical examination so that you will be able to detect changes attributable to the treatment; use the patient for feedback subjectively. If Root doesn't work...modify it until it does work. And if it does not seek a second opinion or refer off.

 

See Craig Payne's past present and future of Biomechanics article. I beleive it was publishsed in JAPMA in 1998. There was a list of problems.

One that bothers me the most is the leap in logic in neutral position casting and the idea that an orthotic made from this cast will cause the foot to achieve this position. What is the logic in casting neutral position? (It may work well that way, but why does it work?) Why cast in neutral position when the patients nearly always stand very close to maximally pronated. Wouldn't we want to capture the forefoot to rearfoot relationship in the position that they stand in?

Reread the explanation of hypermobility of the first ray in the cause of HAV, in Noramal and Abnormal function of the foot. It doesn't make sense. You may think that it is your inability to understand the concept, but it is really a problem with the concpet.

That said there are some important observations made by Root et al. One of my favorites is the idea of uncompensated or partly compensated varus. This is an important concept. Then they had to make it cloudy by trying to make the distinction between forefoot and rearfoot varus. The subtalar joint cannot tell the difference. In their writing there are many astute observations that may take a little effort to separate the wheat from the chaff.

Their observations have to be taken into account when you create your own theory of foot function. This may lead some to believe that a new theory on foot function is really an adaptation of Root et al's work. You have to separate the observations from the theory.

Eric

 

There are a number of problem with the theories proposed by Root et al. I have outlined these in some of the earlier Precision Intricast Newsletters that I wrote in August, September and October 1990:

Inaccuracy #1: The calcaneus must be in the vertical position while in relaxed calcaneal stance position (RCSP) in order for the foot to function normally during gait.

Inaccuracy #2: Each foot has only one correct heel bisection.

Inaccuracy #3: If a calcaneus is everted by more than two degrees then it will continue pronating until the maximally pronated position of the STJ is reached.

Inaccuracy #4: A functional foot orthosis made from a cast of the foot held in the STJ neutral position will position the STJA in its neutral position while in stance and/or in gait.

Inaccuracy #5: The standard biomechanical examination yields sufficient information to predict how that particular individual's lower extremity will function during gait.

Inaccuracy #6: Forefoot deformities are congenital disorders.

Inaccuracy #7: A functional foot orthosis must be made from a rigid thermoplastic without forefoot extensions. Cork and leather orthoses are not functional foot orthoses.

Inaccuracy #8: If a patient stands in relaxed calcaneal stance position (RCSP) with their calcaneus inverted then there must be some abnormality causing the calcaneus to not be vertical (i.e. an inverted calcaneus is always abnormal).

Inaccuracy #9: A foot with an everted forefoot to rearfoot relationship should be treated with an orthosis which is balanced with the heel vertical.

Therefore, the above teachings of Root et al and the professors of podiatric biomechanics at CCPM during the 1970's and 1980's are just an example of some of the things that are wrong with their theories. All one needs to do is to understand biomechanics and the concepts of rotational equilibrium and STJ axis spatial location and MTJ function to see how many of their concepts are just plain wrong and confusing. However, in support of Root et al, without their pioneering work, podiatry certainly would not be where we are today.

I really have no problem with Root, Weed and Orien and all the wonderful things they did for podiatry. However, what I do have a problem with is those individuals (and especially those professors in podiatry schools) who refuse to look at the newest research and theories with an open mind and are still teaching Root theories like their theories are a religion. If they were truly professors who had their podiatry students best interests in mind, they would be doing a lot of thinking about new research evidence and new theories, actually learn some real biomechanics (from biomechanics textbooks) and then acknowledge that the theories of Root et al are largely outdated scientific theories that served us well in the past but need to be replaced due to newer evidence that does not support their theories. Of course, this requires work and concerted effort, which is probably the real reason why many professors will never change their way of thinking and teaching biomechanics to their podiatry students.

 

In addition to Kevin's list I would like to add a general conceptual critique. Root theory is based on position of the foot. Foot position may correlate with stress, but not all of the time. For example a model for sinus tarsi pain is that it hurts when the lateral process of the talus is pressed into the floor of the sinus tarsi of the calcaneus. When you supinate the STJ there will no longer be compression and the pain goes away. However, pain can also go away without changing the position of the foot. All you have to do is reduce the compression forces and you can do this without changing the position.

Anatomical structures fail (hurt) when the stress applied to them exceeds their ability to withstand that stress. Examining the position of the bones of the foot does not give you the full picture of stress. This is why Root et al's theories should be considered outdated.

Eric

 

What types of pathology will a root-device (plus additions) not work on? Is there invariably a better alternative?

 

It's not that a modified Root type device won't work since some would say that all foot orthoses are "modified Root type devices". What is your definition of a Root-device??

The problem is that the prescription protocol recommended by Root et al does not treat all foot problems optimally.