Podiatry Arena members do not see these ads

Dear Craig, Simon, Kevin, Bruce, Eric and all other interested or suitably opinionated.

I've been refreshing my comprehension of pedal biomechanics of late and wondered if you had an opinion on what the 5 greatest mis-truths of this discipline are.

In other words what concepts most people think/ assume are correct, that havn't yet been tested by science or are likely to be.

Will value your thoughts...1, 2, 3 , 4, 5 :) !

Regards. Adam.

1. Excessive pronation is pathologic (its not)
2. Forefoot varus is common (its extremly rare)
3. Foot pronation is a compensation for a structural LLD (its not)
4. 10 degrees is the normal ROM for the ankle joint (its not)
5. Foot orthoses work by changing the pattern of rearfoot and/or midfoot motion (they don't)

__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia
http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University
This is where I am, where are you?

I like Craig's list. My list changes day to day. Not sure if these are "popular" beliefs, or that a lot of people think them to be right, they're just things that I don't like this morning:

1. The foot is a tensegrity structure.
2. The MTJ has oblique and longitudinal axes as described by R,W & O. In fact, anything to do with axes fixed in space i.e., the 42:16 STJ axis and "normal" ranges of motion at joints and their prediction of pathology.
3. High and Low gear propulsion and it's relationship to foot pathology.
4. The effects of variation in functional activities and environment on foot/ orthotic interaction are negated by the fact that we walk on hard flat surfaces.
4. The prescription and manufacture of custom foot orthoses is an accurate and precise process and that foot orthotics work by..... (insert any theory you like, because the truth is that we don't know).

Could have picked dozen's, but these will do for now.

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

As Simon says :) , my list of the current beliefs/things in podiatric biomechanics that bug me most changes frequently. Here is my current list.

1. Podiatrists who don't know what a moment is, don't understand rotational equilibrium, don't know any modelling concepts and don't grasp the importance of tissue biomechanics, but still consider themselves to be "experts" in biomechanics.
2. Subtalar joint axis location has little to no effect on the biomechanics of the foot and lower extremity.
3. Discrete oblique and longitudinal midtarsal joint axes actually exist (and are still being taught by podiatric biomechanics faculty around the world).
4. Neutral position is the rotational position of the subtalar joint that allows for optimal gait function for all individuals.
5. Foot orthosis therapy is all about "correcting overpronation", that high-arched, non-rearfoot posted orthoses casted in foam boxes are better than any others in the world, and that any attempt to evert an orthosis past heel vertical to treat patients with symptoms caused by excessive external STJ supination moments is harmful for the patient.

I could go on but since you only asked for five, I kept it brief.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

FALLACIES in the USA

1) “Podiatric Biomechanics” is synonymous with foot orthoses, with very little attention to footwear and selective stretching/strengthening.

2) Subtalar neutral position is the center of the universe.

3) “Podiatric Biomechanics” is adequately emphasized in the curricula of US podiatry colleges- with well published teachers.

4) “Podiatric Biomechanics” is for those who don’t perform Podiatric Surgery- and the twain shall never mix.

5) All podiatrists, by birthright, are the foremost experts on lower extremity biomechanics despite the fact that most practice circa 1979.

Me thinks I have some learning to do to keep up with these guys, but will contribute this one:

1. Heat molding of shank dependant prefabricated orthotics is a myth (but have to give CP some credit for pointing out the errors of my ways with beleiving this one)

Five more:

1. Foot orthoses work by "locking the midtarsal joint".
2. Foot orthoses work by "preventing compensation for forefoot deformities".
3. Foot orthoses work by "holding the subtalar joint in neutral position".
4. Plantar fasciitis is primarily caused by "overpronation".
5. Functional hallux limitus is the cause of excessive subtalar joint pronation.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

netizens

With you Craig, but since it is Monday and I am counting the ecological cost of watching Live Earth, here goes

i. podiatric biomechanics is a precise science
ii eyeballing is both valid and reliable
iii. skin line calculations are accurate
iv. gait analysis is ideal for checkout
v. bespoke orthoses are better than over the counter foot orthoses

toeslayer

1. Insoles made by casting the foot are "functional" Any other sort are "simple" and do not affect foot function.

2. "Correction" is synonmous with "medial wedging". Therefore if an orthotic does not work it needs more "correction".

3. If a modification works in one patient it works for all therefore if one finds a mod one likes one should use it in EVERY DAMN DEVICE YOU ISSUE

4. Orthotics are incapable of making any situation any worse and therefore can be used with impugnity without a proper assessment.

5. As others have said:-

In the beginning the science was without form, and darkness was upon the land, and the community was as void. And a voice spake into the darkness saying "let there be sub talar neutral theory" and lo there was sub talar neutral theory. And it was good.

On the second day.....
Oh B****X to it; we learned STJ theory at UNI 25 years ago and can't be bothered to update our knowledge so we'll assume thats all there is and make ££££s ( or $$$$$) selling the exact same bog standard STJ neutral carbon fiber devices to EVERYBODY regardless of whats actually wrong with them on the basis that casting the foot makes it a "custom" device even if its always the same prescription! Further, we will patronise the backside off anyone who suggests that any theory or model after STJN gas any relevance or validity whatsoever with snide little remarks to the effect that they are just making things unneccessarily complicated.

Sorry, that rant got away from me a bit.

Regards
Robert

Hmmm...

If both are fallacies, then where does this leave our average suburban podiatrist?

As an 'eye-baller', I choose this as the lesser of two evils. But hey, what would I know.

LL

1. Indications for orthotic therapy has nothing to do with the patients insurance coverage.
2. Everything that goes wrong with a foot can be explained biomechanically.
3. If your knee hurts you must need orthotics.
4. Post Tib dysfunction is always caused by poor biomechanics (like everything else)
5. Fusing the 1st MTPJ, STJ or Ankle is perfectly OK Biomechanically, just no joints proximal to these.

THAT WAS FUN!
DrSArbes

LL

>If both are fallacies, then where does this leave our average suburban podiatrist?

It's a kinda biomagic, and the secrets are known only to experts that charge fees. :-)

Happy Tuesday

toeslayer

Ahh the mind boggles reading the above entries!!
Since what we were taught is incorrect is there any chance of a refund on the university fees?

At the risk of repeating some good ones.
1. Position correlates with stress
2. The Root, Orien, Weed explanation of bunion formation makes sense
3. Black box explanations are acceptable. For example the midtarsal joint locks is an accepted theory even though there is no discussion of the anatomical structures that would cause "locking."
4. Forefoot to Rearfoot can be measured repeatedly, and consistantly, across examiners.
5. Functional Hallux Limitus causes STJ pronation

Cheers,

Eric Fuller

Here's my list for today:

1. Orthoses bring the ground up to the foot negating the need for compensation
2. The midfoot = TNJ and CCJ
3. The foot is fixed on top of an orthoses
4. Because I wear orthoses, I should run in neutral shoes
5. Orthoses improve fertility

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

Great tread started by a newbie !!!

In light of all this cathartic negativity, I started a list of 5 FACTS of podiatric biomechanics and quickly lost confidence. All of my entries had soft words like "can" or "may"- and I scrapped the list. Are there any bold irrefutable truths ??????

5 Facts of Podiatric Biomechanics

1. Obesity and gravity will be very good to the podiatric profession over the next few decades.
2. Those podiatrists that understand mechanical and engineering concepts have an intellectual advantage in treating mechanical problems of the foot and lower extremity.
3. Custom foot orthoses, when correctly prescibed and adjusted by skilled practitioners, are an extremely effective, safe and underutilized treatment modality.
4. Researchers will continue to misrepresent the effectiveness of prescription foot orthoses until they understand the concept that skilled orthosis practitioners do not simply hand out cookie-cutter orthoses to patients without needing to occasionally adjust them to improve patient symptoms and improve gait function.
5. The emphasis on teaching surgery over biomechanics and a lack of post-graduate training programs in biomechanics within the podiatric medical educational system within the United States will result in, within the next two decades, a lack of US trained podiatrists that will be considered experts in podiatric biomechanics.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

1. Since science deals in probabilities, there are few, if any facts in podiatric biomechanics. Our knowledge of the biomechanical function of the foot and lower limb is changing (improving?) day-by-day. However, paraphrasing someone great: "What is a truth today, shall be a half-truth tomorrow and an untruth next year."
2. There is insufficient good quality scientific evidence regarding the efficacy of custom foot orthoses. It is unlikely that there ever will be due to the inherent nature of custom foot orthoses and the relative lack of funding for such research.
3. Too many foot orthoses are mis-prescribed by an increasing number of poorly trained individuals.
4. Patients sometimes wear their orthoses the wrong way around, and still get better.
5. Biomechanical functional capacity is a function of the interaction of the genotype and the environment, thus it is non-constant and unique to the individual at that instant in time- bring on the obese

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

I'll ignore the Freudian typo.

Perhaps Adam had a head start? Was Jim your father Adam? For all who are wondering what I'm barking on about now see Philps, J.W.: The functional foot orthosis. Churchill Livingstone

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

"Since science deals in probabilities....."
I've seen this before and I don't agree. Without Mathematics there is no science.
If I drop a known object inside a vacuum I not only know that it will fall, but at what rate and I can repeat it as often as I'd like. It will drop each and every time. I know this because I can accurately measure the mass, wind resistance and the gravitational pull on the object. I can also measure the time and location of the object within the space provided.
If biomechanics is "probabilities" then it is only due to the fact that we have not progressed to a point where we can calculate, measure and reproduce indices within that field of science called biomechanics.
I think this terminology comes from Quantum Physics based on probabilities of locations of subatomic particles. I don’t agree with this either. It’s only “probabilities” because we do not have the ability (at the present time) to measure more accurately.

DrSArbes

Dr SArbes,

You're probably right.

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

"You're probably right"

That's one phrase my Ex-Wife NEVER said to me!!!!!!!!!

1. Things break when they are placed under more stress than they can handle.
2. Motions are caused by forces and moments (2nd Law)
3. For every action there is an equal and opposite reaction (3rd law)
4. Reduction in stress in an injured structure should allow it to heel.
5. Modeling will lead to understanding how to reduce stress in anatomical structures.

You are probably right, it is important to illustrate the positive.

Regards,

Eric Fuller

Heisenberg uncertainty applied to anatomical structures:
The problem with knowing the exact force in an anatomical structure is that the method used to measure the force will alter the force. Additionally, the expense of accurate measurement may be too high to be performed consistantly. There will always be some art to medicine. I agree we should strive to find and perfect measures in biomechanics, however I doubt that the perfected measures will be used consistently at a clinical level throughout the world.

Another problem, does the pain cause the gait or does the gait cause the pain? Both can be true. Which one are you looking at when you perform your measurements?

I've thought long and hard about what measures would be needed to improve treatment of foot biomechanics. It is really hard to predict forces in anatomical structures. If you chose a clinical condition I could tell you where you would have measurement error that would effect the prediction of whether or not that condition would develop. The measurement error would put you back into thinking about probabilities of damage. I doubt it is possible to progress to the point where there is no measurement error.

Although, I agree with your point that we should try and advance as far as we can so that we can acurately know our limitations.

Regards,

Eric Fuller

Yes....
Here is the great man himself:
http://www.philpspodiatry.co.nz/about-us.html

__________________
Forum Rules |FAQ's | Earn CPD Points
Have you added your location to the map? (Map FAQ's)

Speaking of the book: Philps, J.W.: The functional foot orthosis. Churchill Livingstone; how does one write a whole 180 page book on functional foot orthoses without a single reference to the previously published works of any other authors?!

As far as I'm concerned, this lack of any reference to the previously published works of Root et al in Jim Philps' book constitutes plagiarism.

pla·gia·rism [pláyjə rìzzəm]
(plural pla·gia·risms)
noun
1. stealing somebody’s work or idea: copying what somebody else has written or taking somebody’s else’s idea and trying to pass it off as original
2. something plagiarized: something copied from somebody else’s work, or somebody else’s idea that somebody presents as his or her own

Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

How many references in Root et al's three books?

__________________
Science is the antidote to the poison of enthusiasm and superstition

My location

Ok- we have a good range of facts and fallacies... not easy to come up with 5 new ones, but here goes...
Fallacies-
1- Sports orthoses must be soft
2- 'Rigid' orthoses don't allow the foot to move
3- You can create a 3D orthosis accurately from a pressure map of the foot.
4- If a pair of orthoses do not improve symptoms, then they are not 'working'
5- A 'wear in' period of 2 months for orthoses is acceptable.


Facts-
Following on from above...
1- Sports orthoses can be rigid
2- A rigid orthosis does not stop all foot movement
3- Orthoses should be reviewed to ensure that they are achieving the aims they are designed for.
4- A well designed orthosis should improve function, but sometimes the symptoms are not related.
5- Orthoses should be comfortable under the foot in a very short time.

There are possibly some contentious ones there... I await the grilling.

While I am on contentious 'facts and fallacies'

CP-
OK, I'll bite... I agree that not all pronation is pathological, but is your statement too broad??? Do you include pronation moments in your definition?

Toeslayer-
While I know of many instances where an OTC orthosis may give as acceptable results as custom orthoses, to say that your statement is a fallacy is, in my eyes, a bit of a stretch...
A custom orthoses should always be at least as good as the very best OTC device- if this is not the case, then you have a problem with your custom devices!

__________________
Craig Tanner
Podiatrist
ASPETAR-
Qatar Orthopaedic and Sports Medicine Hospital
Doha
QATAR
http://www.aspetar.com/

Hundreds.

In Volume I (Root ML, Orien WP, Weed JH, RJ Hughes: Biomechanical Examination of the Foot, Volume 1. Clinical Biomechanics Corporation, Los Angeles, 1971), there are 95 references.

In Volume II (Root ML, Orien WP, Weed JH: Normal and Abnormal Function of the Foot. Clinical Biomechanics Corp., Los Angeles, CA, 1977), there are 43 references in Chapter 1, 55 references in Chapter 2, 44 references in Chapter 3, 8 references in Chapter 4, 9 references in Chapter 5, 37 references in Chapter 6, 22 references in Chapter 7, 70 references in Chapter 8, 97 references in Chapter 9 and 88 references in Chapter 10.

In "Volume III) (Root, M.L., J.H. Weed and W.P. Orien: Neutral Position Casting Techniques, Clinical Biomechanics Corp., Los Angeles, 1978) there are no references.

So to answer the original question, "How many references in Root et al's three books?, the correct answer would be 568.

However, on the other hand, in the book by Jim Philps [Course Supervisor, School of Health Sciences (Podiatry), Central Institue of Technology, Heretaunga, New Zealand] (Philps, JW: The Functional Foot Orthosis. Churchill Livingstone, New York, 1990) published 19 years after Root et al's Volume I, there are no references.

In fact, from my reading of the book, there is not a single mention of the prior published work of Drs. Merton Root, John Weed or William Orien within his book even though the first chapter of the book is nearly identical to the Root et al's Volume I. The third chapter of Philps' book discusses neutral position plaster casting with absolutely no mention of Root et al's "Neutral Position Casting Techniques" book published 12 years before Philps' book.

If this is not plagiarism then it is complete ignorance by a podiatric educator to the prior published works of the individuals who spent most of their professional lives starting and developing the field of podiatric biomechanics. Churchill Livingstone should never have published a book like this without any references to prior published works.

__________________
Sincerely,

Kevin

**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College

e-mail: kevinakirby@comcast.net

Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA
My location

Voice: (916) 925-8111 Fax: (916) 925-8136
**************************************************

Think way back to that first lecture I gave you in second year biomechanics....what did I say back then? "Half of what I teach you this semester is wrong, the problem is I do not know which half it is" :)

__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia
http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University
This is where I am, where are you?