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Scanning for Orthotic Fitting

Posted by Elyse B on 10/14/04 at 07:20 (161477)

The last podiatrist I went to had me step on this mat and a computer simulation showed where I needed support etc. The screen showed in different colors etc. etc. Is this how one fits for orthotics or is this a test to see if I need orthotics?

Re: Scanning for Orthotic Fitting

Mark Evans on 10/14/04 at 10:37 (161489)

Elyse - you have entered the arena of CAD-CAM. This includes computer aided design and computer aided manufacture of orthoses. Computer aided diagnosis is a vexed area, especially when addressing orthoses.

I would be scpetical if you only stood on the mat instead of walking several steps (or more...). The foot at rest is not a good indicator of the foot in function. Also the measurements are best takken when wearing your customary footwear. Shoes have a big impact on foot function also.

My opinion - it's a lovely toy to play with and very impressive to 'customers'.But there is no technology that will tell you if you need an orthoses - this decision is determined after the customary evaluation embracing history, examination and appropriate investigations. The key is the biomechanical examination of the patient's musculo-skeletal system together with gait analysis. The evaluation may also include video analysis, and if force pressure measurements can be added, so much the better.

An area of interest to me is how can we, the clinician, really know when the orthoses is working, or at least doing what we want it to do? A reduction in symptoms is a useful indicator but objective signs are hard to come by. The precise modus operandus of orthoses is a hot area. It is perhaps in this area that force plates can assist us to understand how an orthosis has modified a patient's walking pattern. And also to evaluate what is the effect of a modification of an orthosis.

What objective information is there to say custom made orthoses are better than off-the-peg orthoses? I would guess that off-the-peg devices can meet the requirments of say 75-80% of patients with a complaint such as abnormal pronation.

Re: Scanning for Orthotic Fitting

Elyse B on 10/14/04 at 11:30 (161496)

I did walk several steps on it. I was not impressed frankly and it was way overpriced. I wish someone would tell me what is wrong with my orthotics or even if I need them. Frankly I would like to even know if I have PF. What a mess PF is.

Re: Scanning for Orthotic Fitting

Ed Davis, DPM on 10/14/04 at 21:07 (161544)

Mark:
I have been looking at that technology for years. Some of it tries to convert 2-D pressure phenomenon tO A 3-d model. I find that questionable.

Bergmann Labs has produced the best scanner technology to date with a true 3-D capture but have not been overyly impressed with the end product.

Finally, I think that one company has 'got it right' and that company does not market nationally, still quite new. They are called Pedalign and use a unique 3-D capture system that is quite fascinating. The University of Washington became involved in solving a vexing problem for NASA: studying and mapping the topography of Venus without getting too close to that planet's hostile atmosphere. Basically, a system of cameras from a distance is utilized and can achieve a remarkably accurate capture. I will look uo the website on the technology and get back to you on this...
Ed

Re: link for Mark

Ed Davis, DPM on 10/14/04 at 21:15 (161545)

Try this link ( ScottR - you may enjoy this too).

http://grail.cs.washington.edu/projects/ststereo/

Ed

Re: link for Mark

Ed Davis, DPM on 10/14/04 at 21:20 (161547)

Besides the obvious use in orthotic scanning, doing a dynamic capture; I can see other uses. I had mentioned to ScottR (Scott R) - I cannot remember which format gets his attention, the dilemna we have of insufficient material out there to demonstrate biomechanics/pathomechanics. The podiatry profession, not to mention the medical profession as a whole, could use better audiovisual materials to to explain mechanical problems...
Ed

Re: link for Ed

Mark Evans on 10/16/04 at 09:53 (161639)

Doc, I don't know about that. The Brits have a system that will do this and more....check it out : http://www.footpressure.co.uk/d3d.htm