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I wonder if you could give your opinion on the following.

Propsal:

To test X number of biomechanical theories, (three for now) through their application in a foot orthoses, against each other and the no orthotic control, using dynamic gait parameters to be determined.

Hypothesis:

Each test orthoses will have a significant effect on the gait parameters tested against the no orthoses control.

One device will indicate a significant improvement in gait parameters tested against the no orthoses control and the other orthoses tested.


Method:

One subject

One set of "Neutral" casts

One lab to produce all the orthoses

Same base orthoses shell material.

Questions:

What gait parameters should be tested?

How should these be tested?

What acceptible agreed on "normal/ideal" biomechanical parameters can we use to test against?


Your thoughts ?

Graham

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

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Hey Graham

I'm no expert on research but my thoughts are as follows.

Depends on the condition affecting the foot. For eg a foot with a deviated axis might respond better to a Kirby skive than a standard root. Does'nt mean it was better, or even more effective, just that it exerted more of an effect on that patient at that time.

The gait parameters would also be tricky. How would one measure the significance of kinetic rather than kinematic changes?

A study should start with a Null hypothesis rather than a hypothesis. One should always seek to disprove ones theory. Also need to define what constitutes an "improvement" in gait parameters. Movement towards a norm? if so, what norm.

Statistically insignificant. Would'nt show anything.

Unrepeatable. You'd have to use a single cast and duplicate it. (take casts of the cast for eg.)

Might need to blind the lab

What if the different theories required different materials

All the tests are imperfect. Almost impossible to test internal kinetic changes for example. Damn hard to do force plate analysis with insoles and anyway they are only 3 dimensional. External kinematics could be tested with a motion capture system is the best i could come up with.

Also you'd have to carry the test through over time to avoid the "spikeorthotic effect" (TM all rights reserved Kevin Kirby and precision intricast, Copyright 2008). Ie, whan an insole is new the sensory effect of the device may cause concious or subconcious modifications in gait due to exteroceptive change which may well moderate or dissappear in time. Familier to anyone who has ever seen a patient walk like a deep sea diver when you first put insoles in their shoe!

Some evil researcher did a study where they made students sit with their feet in ice water for ages to numb them then watched the changes in their gait. I forget what it showed. Might have been Hylton Menz but my memory is not perfect.

See above
Thats a unicorn. No such thing as a "normal" gait.

The study you propose has far, far too many variables, especially with only one subject! Might also be worth clarifying what you mean by "biomechanical theories". Are we talking insole mods? assessment tools? Types of insole? Without knowing what you seek to test its hard to construct a methodology!

Great idea for a thread BTW, very stimulating.

Regards
Robert

The problem here is that whatever gait parameter you choose to measure if there was a change has to be a parameter that is correlated to a change in patient symptoms or outcome .... so far we do not know what that parameter actually is. Why does it have to be a gait parameter? Why not a clinical outcome measure? (eg the Foot Health Status Questionaire)

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Craig Payne
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Follow me on Twitter | Run Junkie | Latest Blog Post: Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.

Thanks for the replys.

" Shouldn't we be lloking at multiple parameters and seeing what of these an orthoses can change first. Looking at one parameter won't tell us much. Also, if you agree with tissue stress modeling reduction in individual symptoms would likely result in variable parameter changes. I doubt if you could categorically link a specif change to a specific symptom?

Because we can't tell if we have just made the subject different rather than make them better, re: improve gait parameters tested. Isn't t6his the main concern with current Orthses research?

Graham

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

BUT, we don't yet know which gait parameters are clinically relevant.

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Craig Payne
__________________________________________________ ___________________________________
Follow me on Twitter | Run Junkie | Latest Blog Post: Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.

Do we not "know" what we believe to be ideal in certain parameters of the gait cycle. We also know that "foot orthoses" can improve symptoms. Hopefully this is by bringing the parameters we know should be ideal closer to the ideal.

So by testing pre orthoses and with orthoses ,with various theoretical applications, would we not identify the ortoses prescriptions which bring gait parameters closer to the ideal, and then see if theses devices also relieve symptoms?

graham

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

I don't!

What is, for example, the ideal position of the Sub talar joint during mid stance?

Is the same ideal for everybody regardless of physiological variation? Regardless of the nature of function?

State, if you will, the ideal you seek to work towards.

Regards
Robert

I used to know! Life was simpler then (bit like when 10 degrees was the normal for ankle joint dorsiflexion)

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Craig Payne
__________________________________________________ ___________________________________
Follow me on Twitter | Run Junkie | Latest Blog Post: Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe
God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.

So when Kevin reminded me to eloquently that he hasn't talked about "Root" for a long time. Did he mean that he has just moved on to another part of the "Theoretical tree" further away from the front line clinician but still of no practical use?

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

Memories memories.... Funny how the more you learn the less you know! I remember when Simon introduced me to the concept of the triple interface. I lost a lot of sleep that week! Ruined everything i'd held as fact.


Careful graham. Thems fighting words.

I think to imply that moving away from root is to become "theoretical" and "of no practical use" is erroneus in the extreme! I suspect what Professor Kirby means is that we now have a rather fuller understanding of biomechanics (due in no small part to his own contribution) and that to rely on 40 year old models is to limit our understanding significantly.

The front line clinician is, IMO made more effective by an understanding of good theory. The two are inseperable.

Regards
Robert

Indeed. And as a front line clinician who now practices 100% sagital plane facilitation with a heel skive here and there, I agree totally. However, creating biomechanical theory and believing it to be a greater understanding is a false doctrine. Unless we devise an objective baced framework on which to test the theory how will it ever become practical to the mainstream, "non accademic" practitioners?

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

Yes I noticed your profile as "sagital plane facilitator". Interesting approach. What do you do if the problem is not caused by sagital plane blockade? Or do you contend that 100% of pathology stems from sagital plane dysfunction.

Is not sagital plane progression just another "theory"?

As to how theory finds its place in everyday practice, I suggest that this is inevitable! The clinician garners data by observing/ assessing the patient, processes it through their understanding of biomx and builds their treatment plan based on this. The only variation as far as I can see is what models / theories the clinician finds helpful.

I'mstruggling to see where you are coming from here. Perhaps an example of a theory you feel is not applicable in frontline practice.

Regards
Robert

Seeing as we walk forward in the sagital plane, any problem which inhibits "ideal" foot function would be regarded as inhibiting efficient motion in the sagittal plane. The diference is we look at the same thing you do but from a different perspective.

The theory was developed based on observations, using F-Scan and video analysis, looking at changes in objective data with and without an orthoses. When using a conventional device the data anomolies merely changed but did not disapear. When an orthoses was made that actually improved the data to a more "ideal" situation the prescription could not be explained using conventional theory, therfore a new theory evolved to explain the treatment. Thanks to Danaberg.

How then was "Rootian" principals replaced and what has replaced it? If the majority no longer believes in a conventional varus posted orthoses ,for example, and incorporates a new theory into their practice. What justification can they use for this if it is"just another theory"? How can this new approach be demonstarted to be any better than the previous one. Sagittla plane facilitation utilizes the technology we have available to see if the orthoses actually makes a difference.

__________________
Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

Robert

I think you'll find that was in relation to your gunslinger reference and Graham just came in to the saloon and fired a shot at you, or came out into the street, not quite sure which he is?

LoL Dave

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Descartes seems to consider here that beliefs formed by pure reasoning are less doubtful than those formed through perception.

It seems obvious (but I can't see where it has been mentioned in this thread so far) that in the interests of accuracy someone (its going to be me, obviously) should point out that any measurements taken with F-scan or any other vertical loading gait analysis system are only measuring gait on one surface - a flat, hard one.

Looking at "normal" gait parameters, one of which is the Force-against-Time curve, on a hard, flat surface, does not accurately tell us whether our gait is normal or abnormal (except in those circumstances where the gait is obviously pathalogic).

This is not to say that I consider vertical loading systems (VLS) useless, far from it - I use a Tekscan Mat myself very frequently. It is very good at recording "gross" gait parameters such as no heelstrike, very early heellift, non-weightbearing 1st MPJ etc. The problems with VLS are:
The system is incapable of collecting truly repeatable data due to diurnal variation.
Data collected is only representative of the subject walking on one surface.

Data thus gathered should not be taken as "gospel" (as it so often is). VLS systems should be recognised as having limitations and used accordingly.

Regards,

Sorry to state the obvious, but isn't this what we do 99.9% of the time? Isn't this the reason that creates the need for compensations and pathologies over time?

Just a thought!

Graham

to all those in Canada, I hope you all had a great Thanks Giving weekend.

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Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

This was in answer to "In response to my point about "It seems obvious (but I can't see where it has been mentioned in this thread so far) that in the interests of accuracy someone (its going to be me, obviously) should point out that any measurements taken with F-scan or any other vertical loading gait analysis system are only measuring gait on one surface - a flat, hard one. "

Graham, check out some pavement, insides of shoes, going uphill and coming downhill, then tell me if you stick by your assertion about being on a hard flat surface 99.9% of the time.

As most of us don't walk around bare foot, unless you compare this to inshoe with and without orthoses it's not very useful.

Agreed, but at least it should be used if you really want to know more of what your orthoses is doing, or perhaps not doing.

__________________
Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

Graham,
Unless you are collecting data from your patients in a normal environment your data is only showing how orthoses are working on a hard, flat surface.

Barefoot data collection is not less useful nor more useful than in-shoe data collection, just different. It records certain gait parameters. It is fairly rough and ready. It is useful for the reasons I mentioned before, and also useful as a patient education tool.

Unfortunately there are simply too many variables present to make either version of VLSs very accurate - I'll mention a few:
Diurnal variation, inability to test on more than one type of weightbearing surface, how the patient/subject is feeling on the day, proximal (to the ankle) joint/tissue disfunction or pathology, footwear (for in-shoe systems).

DH

The hard flat surface, while man made and not ideal, IS the norm for most people most of the time.

The variables exist in all aspects of treatment applications. Utilizing the footwear of the client on a surface which IS the norm for the majority of the time, we can at least demonstrate a positive/negative affect, and fine tune as necessary, our orthoses to be as functional as it can be for "most" situations. In cases where there are special considerations re: surface, the F-SCAN is mobile!

Question? How do you, beyond outcome measures, determine what prescription to apply to your orthoses and what effect these have on multiple gait parameters/variables?

__________________
Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::

Are you saying that your pavements and walkways in Canada are absolutely flat and that there are no hills/dips

I post most of my prescription orthoses 2 degs FF, sometimes I use a RF post too. Its a little simplistic, but it seems to work quite well......

Agreed-upon outcomes (between pt/practitioner) are the best way to measure how well orthoses are working (IMO) since we don't know for sure what "normal" parameters of gait are. I think CP mentioned in a previous post that normal for one pt may not be normal for another?

Graham, you also stated:
"The variables exist in all aspects of treatment applications" which is absolutely true. However we are discussing, and you are defending a technique which puports to scientifically measure absolute or near-absolute gait parameters and alterations of gait parameters using orthoses. You are also suggesting that your results can be extrapolated to include gait on all normal surfaces, which you insist is mostly (you suggested 99,0% of the time) hard and flat, like a gait lab, or clinic floor if you like.
For me the existence of those variables alone will ensure that your data cannot be as accurate as you suggest.

Would you like to comment on diurnal variation and how that might affect your data?

Come on David, you are being podantic. Despite variations in cambre and pitch the basic interface between the foot and shoe and shoe and foot is Flat! Not what the foot was designed to perform on every step.

2 degrs FF Valgus or varus? RF post when, why and what? Why? Based on what biomechanical framework?

Are they? What have you changed with the orthoses? Is it causing pressures and alterations in timing which, with your extensive knowledge, would concern you? Has symetry been established? Have you used the same Rx for both sides? How did you determine that the same Rx was approriate for both sides?

We have a good idea what we would regard as ideal (Winter/Perry et al). Agreed, what is normal for one is not normal for another. Therefore, why would you give basically the same Rx to everyone?

Not absolutely scientific, but adding more objectivity than just the human eye and a belief structure. I'm not suggesting that the data is as accurate as we would like, only better than without it! Or are you concerned with what you may find?

No! This doesn't account for night shift workers

__________________
Graham Curryer

None of us know what we are doing, but some of us know more about what we are not doing than others!::