Simon and Colleagues:
In a message dated 1/12/00 1:18:46 AM Pacific Standard Time,
[log in to unmask] writes:
<< I read with interest the article in the Sunday Times "culture" magazine
9/1/ 00 entitled: Step into the future. For those that didn't see it, this
article talked about a system being developed by Janice Bruckner for the
prescription of bespoke footwear using optical scanners and CAD/CAM
technology. The article suggests that the "prescription" will be largely
dependent upon Buckner's observations of variation in facet configuration in
the STJ. A comment within the article from Tom McPoil suggests that this
approach is "somewhat shallow" since it only takes into account one joint-
fair enough.>>
I would suggest that it is quite a leap of faith to suppose that STJ facet
configuration can accurately predict optimal shoe fit and shoe function for
an individual. Shoe fit and function are dependent on many more variables
than STJ axis position and range of motion.
<<My question is: what effect does facet variation have on the centre of
rotation of the STJ? Although we model the STJ as having one centre of
rotation in reality does the presence of multiple facets indicate multiple
centres of rotation? Furthermore, how can facet configuration be accurately
predicted without opening up the joint?>>
I believe Jan has done considerable research on STJ facet configuration in
foot skeletons. However, I don't think that I have read an article of hers
which shows how facet configuration can be accuately predicted clinically.
I do know she was working with MRI scans to produce three dimensional images
of the STJ facet configuration at one point a few years ago. Maybe to get
proper shoe fit we need an MRI scan of the patient?
Researchers have shown that there are multiple discrete STJ axes present (a
bundle of axes) within the talo-calcaneal joint area. From my clinical
experience, I suggest that no individual has a single STJ axis which is in a
stationary position throughout the entire range of motion of the STJ axis.
However, it is quite convenient to model the STJ axis as having only one
stationary axis when lecturing to students and podiatrists since the spatial
movements of the STJ axis throughout the STJ range of motion is probably
quite slight in most individuals.
Cheers,
Kevin
***************************************************************
Kevin A. Kirby, DPM
Assistant Professor of Biomechanics
California College of Podiatric Medicine
Private office:
2626 "N" Street
Sacramento, CA 95816 USA
Voice: (916) 456-4768 Fax: (916) 451-6014
***************************************************************
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|
