What value barefoot assessment?

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The data from a recent study looking at LAA (SNA/Feiss line) in barefoot, shod and shod with insole, static and dynamic

Barefoot static 140.18
Barefoot dynamic 139.83

Shoe only static 156.65
Shoe only Dynamic 154.27

Orthotic and shoe static 154.32
Orthotic and shoe Dynamic 154.12


The study thread is here.

Now the study, rather bizarrely, looked at the ability of static to predict dynamic patterns. And lo, it saw that they were good. Praise be.

But the far more interesting element of this data for me is how barefoot assessment (static AND dynamic) varies from the Shod situation. That is a HUGE difference.

Much is written about how well (or not) static assessment predicts dynamic. Should we be more worried about how well barefoot assessment predicts shod performance?
Most static WB assessment and a lot of gait analysis is done barefoot. Most people function shod in the real world (unless your name starts with "barefoot").

What say you?

 

Hi Rob,

I say that the study is flawed - it's too small a cohort to reveal anything meaningful.

But I take your point about barefoot gait analysis (I do it all the time) and how it's different to shod gait.
Lets have a look at what else affects gait (in the real world).

1. Footwear. Unless each pair of shoes is exactly the same, with exactly the same wear, then gait will alter depending on which shoe is worn.
2. Surfaces. I know I bang on about hard and flat, but in reality most outside surfaces do vary a tiny bit - even pavements.
3. Normal diurnal variation. Back, hip and knee joint stiffness (varying degrees of during the course of the day) will affect gait I would have thought.

Podiatric Biomechanics cannot be a precise science - I think this illustrates that fact perfectly.

Barefoot gait analysis using a system for capturing objective data is a well-documented, useful clinical tool. I'm not about to be persuaded otherwise by a single study with a dodgy conclusion carried out on 17 subjects.

 

Hey David.

Playing devils advocate here you understand.

Not sure I entirely agree that 17 is too small a number to show anything. Granted it is a very specific sample of a very specific demographic and a single type of shoe. But it is a very, very large difference in averages.

Ben goldacre

Does it show that barefoot assessment is never predictive of shod performance? No. Even if it were 17,000 it wouldn't, because barefoot might be directly proportional to shod. If arches always raised by 20% then different as it was it would still be clinically useful.

It does, however, show that in some subjects (not bizarre subjects) and some conditions (not bizarre conditions) the barefoot LAA bore little resembelance to the shod condition. I think that is enough to ring a note of caution!

The study is a good barometer of how many (most) people think. They're patting themselves on the back because their static test predicts the dynamic and completely ignoring the vast, vast gulf between their dynamic condition in vitro to the real world.

Yeah, you were one of the first to teach me that.

Hmmmm?. What data, and is that data representative of the actual in vivo function of the human?

 

By the by, I just stuck the data for barefoot dynamic and shod dynamic through a 2 tailed T test and got a P of <0.0001

 

I think we broadly agree here (which is not much use for a debate).

Barefoot gait analysis with objective data.
As you know I use a Tekscan mat system. Easy to use, portable, reliable, and gives good repeatability if used properly. There are other brands of gait analysis system which may just as good.

As a couple of simple examples of what it can do, in paediatrics it captures in-toe gait nicely. It gives as an objective picture of what we see when we walk the child along the corridor.
Paediatric flatfoot. How many times has the GP referred a paediatric pt with flat feet to you, only for you to look at the feet and say (probably with some exasperation) "these are not flat - did he look at you standing on a carpet"?

The Matscan can give objective data about flat feet (or not), abduction angles during gait (which are always a good match for what I see when I walk the patient with shoes on.

What it can't do is give specific data which can be extrapolated out as being true for that patient every day, all day. It can record data which can be used as guidelines. It's a useful tool nevertheless.

Now that small cohort - I have no probems with small cohorts per-se, as long as the results are clear and fit the data.
I did my Pod degree final year research project on the vaso-activity of two local anaesthetics. Did anyone else wonder at that leaflet in the Mepivacane tin which said mepicacaine is a slight vaso-constrictor?

I used a cohort of ten. I was advised, strongly, that as a pilot project it would work, and a carefully worded meaningful conclusion could be drawn. Had I submitted this as a piece of stand-alone research it would have been marked down, no doubt about that.

Really though, I query the validity of a study which pronounces a firm conclusion based on that published data. That means I question the whole thing, which is why I'm not happy drawing any conclusions from the study.

Based on my final-year project results (and the Anaesthetist member of the Ethics Committee I had to go before was already pretty certain about this) Mepivacaine is not a vaso-constrictor, not in the great toe anyway.
I found some robust evidence that it is a vaso-constrictor in rat spinal tissue....

 

Rob,

I agree that (sample) size isn't everything. Certainly in qualitative research people have completed PhD's with a sample of 1. But when looking at quantitative data and then potentially extrapolating our findings to a population its a bit more important. It's all about the 'power analysis'.

The more I look at those figues from said study the less convinced I become. Remind me (as I don't have the article to hand); I know they were the mean angles, but were they the mean of just one foot (n=17) or did they use both feet for each subject (n=34)?

I'm with you and DH on the in-exact science we all practice, and kinda see your what you're shooting at re the barefoot/shod point. But as long as we are aware of our limitations I think that's the best we can do. I always check 1st MTPJ range/stiffness barefoot - but I'm pretty certain that will change in a given shoe, on a given terrain during a given activity. I'm certainly not about to change my clinical practice based on the aforementioned study (as I'm sure you aren't!). Speaking of which, does anyone here actually use the LAA on a daily basis?

 

This was hit home for me when we started doing the Lunge test in the shoe. We were seeing people who where clearly limited ankle joint ROM when barefoot, but as soon as you put the shoe on (with a cm or so heel raise), range of motion was easily adequate.

Think back to when life was simpler and 10 degrees was the normal ROM for the ankle joint (with STJ neutral etc etc) ... that foot then functioned in a shoe with a 1cm heel raise, so the minimum required is only probably 5 degrees or less. In the past if I measured 5 degrees, they needed treating ... food for thought.

 

Craig,
Apart from fashion, surely that's why footwear manufacturers incorporated a heel in mens shoes (come in SK)?

Comfortable shoes sold/sell (to the masses) whereas uncomfortable shoes didn't/don't.
A little heel (on a hard, flat surface) is much more comfortable for most people ( M and F) than no heel.

Remind me - that 10 degree normal dorsiflexion was eventually discredited - right?

 

I don't think it was necessarily discredited. in some work we did in measuring how far the tibia moved over the foot before the heel came off the ground at ground while walking at different velocities, the mean was 9.9 degrees!, BUT, the subject specfic variation was substantial - some subjects only needed 0 degrees and others needed 15 degrees. ... but that was done barefoot!

 

My poor wording (I blame a good afternoon clinic, long drive home, and several glasses of wine)

The subject specific variation was substantial is certainly what I found (n=100+), and I guess is what I was trying to say - thanks.

 

RSCP should be vertical, Ankle dorsi should be 90 + 10, forefoot perpendicular to rearfoot, sub talar joint in neutral in static WB...

"Can it be that it was all so simple then
Or has time rewritten every line
If we had the chance to do it all again
Tell me - Would we? Could we?"

I actually saw a teeneager with all of that the other day. They were all kinds of broken.

 

I have just posted some pics in this thread which show how barefoot and shod assessment may not agree...

 

Attached article worth a read

 

Ian:

You....da....man!!!

 

Watching Craig T´s videos on the overpronation thread reminded me of another curve ball re assessment.

Say we do an assessment on a treadmill and issue a device for over ground running.

tis a tangled web....