Prescribing Orthoses: Has Tissue Stress Theory Supplanted Root Theory?

Jeff,

One of my new patients today. I get this all the time.


Good afternoon Dr. Kiper. I am writing to you after reading up on you web site. I guess I am looking for a miracle. As you state on your web site, I am one of those patients that just cannot get relief from custom orthotics. I am on my seventh pair in the last 4 years. Since the pain started in my feet I have developed a hammer toe on my left foot, and I can no longer walk without shoes on, my feet kill all the time. I am a 49 year old very active male. I am a 5th degree black belt in taekwondo and have crazy pain in my feet and constant throbbing in my calves. I can no longer run because of the pain. Every podiatrist that I have seen claims that the previous one didn’t know what they are doing. I am tired of feeling pain. Do you think you can help me. The big problem is that I am in Montreal,Quebec, Canada. This pain is ruining my life. Thank you in advance for any help that you can provide.

 

Ereic
Let me rephrase my question:

At what point (from just before midstance to the end of midstance) are you able to stop STJ pronation?

 

Why do you care when it stops? The more important question is what stops it.

 

Eric,

I don't agree with what you said. Tell me when it stops barefoot and with a well fitting orthotic.
Then we can discuss that.

 

It is variable. Pronation of the STJ stops when the supination moment is high enough and applied long enough to bring pronation angular velocity to zero.

I've said lots of things. Could you at least quote what you disagree with?
Eric

 

Eric

I disagreed with the fact that you thought when pron stopped wasn't impt to know. I think it is impt.

Everybody went crazy when I used the term instability moment, yet here you use sup moment. Well, when is the supination moment in this foot??

 

I've never liked the term loss of windlass mechanism. The windlass is still there. I'm not sure what people mean when they say loss of windlass.

Trevor, why do you think that loss of the windlass will increase load on the peroneals? By loss of mechanical advantage of peroneus longus are you referring to the diagrams that are in Normal and Abnormal Function of the foot. I disagree with that analysis. The first ray does not plantar flex because the base of the metatarsal is pulled downward. It plantar flexes because there is a rearward pull on the base and this creates increased compressive forces at the base of the metatarsal and that creates a force couple that creates a plantar flexion moment on the first ray.

I agree there is sort of an imbalance with post tib dysfunction. When you think about rotational equilibrium about the STJ there are more sources of moment than just the peroneals and posterior tib. There is also the ground. If there is a large pronation moment from the ground, you could still reduce the peroneal pronation moment to zero and the posterior tibial muscle might not be able to produce enough supination moment to over come the pronation moment from the ground.

Eric

 

Dennis, do you understand the different definitions of moment. There is a moment in time. And there is a moment that is the same as torque. Moment = force x distance. Moment = moment of inertia x angular acceleration. So to start or stop a rotation you need a moment (= torque). If orthotics alter motion, they have done so by altering moments. Fluids can apply a moment. If you look at the center of pressure of a fluid you could calculate a moment being applied by that fluid. Someone who understood hydro dynamics would know this.

I'm not going to go back and look and see if instability moment (point in time) makes sense. Dennis I'll let you make the case that the "time" definition made sense.

Eric

 

Eric,

I'm asking where in the gait cycle is that supination moment in time? I don't need you to tell me what a moment is,

 

So, you can see why we went nuts when you talked about instability moments.

Why do you care when the supination moment is applied to the STJ?

From the equation Moment = moment of inertia x angular acceleration. When you see the pronation motion decelerate, a supination moment is being applied.

Eric

 

Eric,

Your answering my question with a question. Why can't you answer the question. Your moment formula does not answer the question either.

A simple biomechanical question of where is the supination moment you are describing in your formula occur in the stance phase of the gait cycle??

 

When will a moment occur Dennis ?

In this case a Supination moment that stops the angular velocity of pronation around the Subtalar joint axis.

Is that what you asking a specific time point

Eric already told you,

it is individual and occurs at different times

 

Eric and Mike

Are you saying the variable time is due to the different structural shapes and rom of each foot?

dennis

 

It's a simple rate of change of angular momentum problem.

 

Then within a few nano seconds of each other, where in the gait cycle does this happen??

 

it will be unique to the individual and the environment, since the phenotype (in this case being the point at which pronation motion is stopped ) = Genotype + Enviornment + (Genotype x Environment) + measurement error.

Where, the environment is all non-genetic factors.

 

I realize its unique to the individual and environment, but read the question for a foot in at your office under controlled conditions??

 

Simon answered your question


you want a time during the contact phase of gait ?

No one can give you time, it will be different from person to person and even in an invidual under different conditions.

 

It's still unique to the individual, for the reasons I outlined above. if I got the same patient to come in on two consecutive days and measured the same variable, it should be different- part of this will be measurement error, part will be due to "normal" between-day variation because by definition a phenotype is only valid at the time it is measured. That's how life is... To quote The Verve: "I'm a million different people from one day to the next".

 

So, with all the variables and all the nano seconds, from the same person or another on different days or not would that "moment" (approximate) occur in the gait cycle?

 

Moment = force x distance or, "moment in time"? https://www.youtube.com/watch?v=K_t4UyYh9Ds

 

to quote Eric again

so whenever that is

Some early, others late, or not at all and some when Root et al suggested it would

 

Root et al also suggested all of the above Mike. For the ideal foot, they created graphs to demonstrate the direction of motion of the STJ. However, in "abnormal" feet, they discussed a variety of conditions and situations in which the STJ would not move like it does in the "normal" foot.

Jeff

 

Because no one is able to really answer specifically, is because your whole approach is not based on any mechanism of physics.

so whenever that is

Some early, others late, or not at all and some when Root et al suggested it would

In another 500 years, none of you will still be able to answer based on your technology.

I can tell you to the moment of the biomechanical motion, when and where in a gait cycle, I expect to see a “moment in time”

If you think you know, what's your best guess on whether pronation at the STJ stops 1st, or does pronation at the MTJ stop 1st??

 

OMG....SMH.

 

except they did not do it for every individual and therefore has little meaning in the real world.

individuals with whatever condition will not go through the same motions at the same.

good teaching tool to get people thinking though

 

Keep hitting your head, that's fine

 

There are about 20 people in the world who on the day the measurements were taken we can tell the exact timing of that Pronation of the STJ stops when the supination moment is high enough and applied long enough to bring pronation angular velocity to zero

those who have undergone the bone pin studies.

The rest of the time it is at best educationed guesses.

even in shoe measuring systems are not accurate enough to work it out exactly

 

Your grasp of Urban acronyms is only rivaled by your lack of biomechanical understanding...but, it appears you're in good company on this forum.

http://www.urbandictionary.com/define.php?term=smh

 

well that's funny always thought that wS smack my head

as for the rest no wonder people put you on ignore

 

Hear, hear! :drinks

 

Mike



individuals with whatever condition will not go through the same motions at the same.


I disagree, regardless of their conditions (with some anomolous exceptions), they go through the same motions. The same instability moments, abduction-eversion and dorsiflexion.
Those are the motions. At exactly what specific time, doesn't matter if you look at the whole picture.


There are about 20 people in the world who on the day the measurements were taken we can tell the exact timing of that Pronation of the STJ stops when the supination moment is high enough and applied long enough to bring pronation angular velocity to zero

I never asked for an “exact” moment of time


What separates their pathologies are the variety of other factors of biomechanics and where the biomechanical weaknesses manifest over decades.

BTW--I noticed no one responded to the fact, that your technology is not scientific???

 

"That's funny...always thought". You would've been better off stopping there. Why don't you do something novel and, say...learn from your own patients? That may be a "foreign" idea, but it works. Instead of depending on academics to perform your own thinking for you, why not follow your own path, use your own experience that your patients also represent, and formulate your own ideas? Perhaps that is why/how I determined the source of GP's in children...and eventually made the anatomic/neurologic connection to RLS.
..the first step was to ignore most of the academics. But let me ask you the following...

1) what pathology has TST ever resolved?

2) how has TST changed the way you examine patients and write Rx's for orthotics?

3) please explain how a "supination moment" occurs in the gait cycle after mid-stance

Take one or all of the questions above and answer them...this is where the rubber meets the road...isn't it? Or...you can place me on ignore like Simon has because he can't defend an indefensible position. Good luck...(the sound of Jeopardy music playing in the background).

 

Uh Dennis, that is exactly what we said. The exact time of the motions don't matter. Although, you still haven't explained what you mean by Instability moments.

What you asked was

It was hard to tell what you were asking. One way to interpret that is asking for an exact moment in time. When you write, your sentence structure doesn't make it clear which definition of moment you are using. I was going to give you the benefit of the doubt that you do know difference between the two definitions. I'm not sure that I should.

If you read my center of pressure and windlass papers I don't see how you can say there is no science. If you throw some criticism out there, which is obviously incorrect, without any explanation, why should you expect a response.

I was going to let your quote just sit there as it collapses on its own. However, since you asked why no one responded, I will point out your criticism makes no sense. How do you expect a piece of plastic, or a bag of silicon, to tell us when a supination moment is applied.

Eric

 

You the funniest ever. I'd go for 3) Here I go....... supination moment occurs when there is a force acting medially to and at a perpendicuar distance from a joint axis that is incliined to all three cardinal planes. It occurs during the gait cycle after midstance by the reaction with the portion of the foot in contact with the ground that is medial to the joint axis of interest and from the contractile activity of the muscles that are active during this period that have their insertion which are medial to the joint axis of interest, all this multiplied by that old Devil gravity and any other acceleration, having their way with you. As anyone or anything ever had it's way with you, Dr Hunnybun?

Bless your cotton gusset drhunt3.1459265....

 

Dobbs

It occurs during the gait cycle after midstance by the reaction with the portion of the foot in contact with the ground that is medial to the joint axis of interest and from the contractile activity of the muscles that are active during this period that have their insertion which are medial to the joint axis of interest, all this multiplied by that old Devil gravity and any other acceleration, having their way with you.


But, the muscles that are active at that moment in time don't effect resupination until heel off. Otherwise the muscles do not have enough strength to resupinate a partial instability within the joint and allows the “unlocking of the rest of the foot”--

BAD TECHNOLOGY

 

Eric

(you)Uh Dennis, that is exactly what we said.

(me) What? (Mike) individuals with whatever condition will not go through the same motions at the same.

(me) How is that the same?



It was hard to tell what you were asking. One way to interpret that is asking for an exact moment in time.

Rubbish


If you read my center of pressure and windlass papers I don't see how you can say there is no science

I've repeatedly said, there is science in biomechanics including your papers, but THERE IS NO PRINCIPLE OF PHYSICS that your technology is predicated on. So all you have is theory MIXED with science.


I was going to let your quote just sit there as it collapses on its own.

Please do

 

Wow, wow, wow, sweet child of mine. The question was: 3) please explain how a "supination moment" occurs in the gait cycle after mid-stance. The question wasn't about resupination, it was about supination moment- two different things... i'd like to say as well you know, but you don't know because quite frankly, you wouldn't know your arse from your elbow when it comes to talking biomechanics, as evidenced above. Nevermind. Of the sub-genii writing her right now, I suspect you are the most sub-genius and as such you have the greatest future within the Church. You can apply to become an ordained minister here: http://www.subgenius.com/scatalog/membership.htm

 

Dobbs! I can't believe it...you're actually trying to be serious?

"It occurs during the gait cycle after midstance by the reaction with the portion of the foot in contact with the ground that is medial to the joint axis of interest and from the contractile activity of the muscles that are active during this period that have their insertion which are medial to the joint axis of interest"...

So let me get this straight....according to you, GRF would impart a "supination moment" even without the muscles, (which you don't mention by name, but generically), just because some of that force 'may' be medial to the axis of rotation?

You probably should've stayed consistent with your MO, because your description is truly sub-genius. Remove all the effects of the peroneal longus, Posterior tibialis, and, in particular, the Anterior tib, and the foot would never realize supination to overcome GRF. Throw in the triceps surae, and this is most certainly the case, (although that muscle group doesn't follow your description of medial insertion). In other words, GRF will impart a pronatory force on most, if not almost all feet...it takes something else to provide enough force to overcome pronation. Root has a full description...perhaps you should check it out.

And here...check this out:

http://www.podiatrym.com/Biomechanics_Footwear_Sports_Podiatry2.cfm?id=1632

 

Dobbs

The question wasn't about resupination, it was about supination moment- two different things..

It is the same