Director, Gait & Biomechanics Lab
Phone: (502) 582-7657

Thanks to all who responded to my inquiry.

Original Posting:

I have been asked by a physician I work with to post a query. Please respond
to me & I will post a summary of replies. Thanks.

We're interested in measuring load transmissions across the wrist joint but
do not have an effective pressure transducer or system for measuring the
forces transmitted across the articular surfaces of the wrist joint. The area
of the relevant joint surfaces varies from 2-4 cm2. So far we have tried a 4
fingered system by Teckscan, but the sensors are too large and are unstable
in the joint. We have also tried Fuji film, but this only allows 1 pressure
measurement at a time & we would like to conduct several measurements at a
time in response to loads applied. If anyone has tackled this or a similar
problem I would very much like to know more about your methodology. I thank
you in advance for your help in this matter. Vivian Lees, M.D.

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From: (John A. Hipp)

The following ref is a good place to start:

An KN, Berger RA, Cooney III WP; Biomechanics of the wrist joint.
Springer-Verlag, 1991

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From: Douglas Chang

This might be helpful:

1. Kristal P; Tencer AF; Trumble TE; North E; Parvin D.
A method for measuring tension in small ligaments: an application to the
ligaments of the wrist carpus.
Journal of Biomechanical Engineering, 1993 Aug, 115(3):218-24.


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From: dieter rosenbaum


We are currently working on ankle joint loading and are using
Fuji film because it is thin and can be cut to the needed shape
of the joint surface. I agree that it is a very time consuming
method since we have only one shot in each loading condition.
We have to conduct several (up to 60) measurements in different
joint positions and experimental conditions and it is a pain in the ...

Yet it seems to be an appropriate way of looking at joint loading
since I could not find another available method. Other sensors like
FSR's or Tekscan seem to be too unreliable since they apparently
change their loading conditions with repeated loading. I also looked
at PVDF film (very thin, down to 25 mikron) but it is very temperature
dependent and appears to be suited for highly dynamic loading only
(apparently used for some kind of shock wave measurements).

I would therefore be very interested if you would find anything that is
worth trying and would appreciate if you could send/summarize the other
responses you get.

Sorry that I do not have THE solution.
Good luck,


************************************************** **********************
* Dr. Dieter Rosenbaum *
* Abteilung Unfallchirurgische Forschung und Biomechanik *
* Universitaet Ulm voice0)731 - 502 3492 *
* Helmholtzstr. 14 fax: (0)731 - 502 3498 *
* 89081 ULM email: *
* Germany *
************************************************** **********************
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Have a look at a paper by Hara et al. who use a pressure-sensitive
conductive rubber at the radio-ulno-carpal joint.

Hara, T., Horii, E., An, K.-N., Cooney, W.P., Linscheid, R.L. and
Chao, E.Y.S.
Force distribution across wrist joint: Application of pressure-
sensitive conductive rubber.
J. Hand Surg. 1992; 17A:339-347.

This may be of some help to you.

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Victor Waide B.E.
Bioengineering Research Centre
Mechanical Engineering Department
University College Dublin
Belfield, Dublin 4

Tel: +353-1-7061752
Fax: +353-1-2830534


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From: Jack Kotovsky

Dear Dr. Rash;

I am fabricating a 2-D, contact-force transducer array to measure
intra-articular joint loads in the knee. The design could be applied to
a number of different joints by trimming the array to size. For the
knee, the array measures roughly 3x5cm and incorporates approx 1500
independent sensors in a cartesian grid (inter-sensor spacing of less
than 1mm). The sensor will have a thickness comparable to a Fuji film
packet and will be capable of repeated and dynamic measurements. The
array is flexible to permit conformity to the complex curvatures of the
knee. I expect to complete the fabrication of this device within the
year. Feel free to contact me if I may provide any additional information.


:::::Jack Kotovsky
::::H) (916) 758-6278 (SLUM-ART)
::::W) (916) 752-2713
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From: Novel Biomechanics Lab

Dear Vivien

I recently wrote to you from Novel telling you about a research project that we
have applied for to develop an inter-articular sensor.

Although it is probable that this project may take a couple of years to come to
fruition, I would also like to add that we are always willing to cooperate with
anybody who has any good new ideas! So if you are interested in talking to us
about this, please, please, please get in touch with us.

Very best wishes

Anna Hayes

Dr. Anna Hayes
Biomechanics Research
Novel GmbH
Beichstrasse 8
80802 Munich
Tel: +49 89 390102
Fax: +49 89 337432

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From: Thomas W Kernozek

Dear Vivien and Gregory,

Contact Novel Inc ( makers of pressure distribution
measurement equipment. They may be able to help you out. The contact is
Susan Diekrager (612-332-8605).

Tom Kernozek, Ph.D.
Thomas W. Kernozek, Ph.D. Y " Y "
University of Minnesota / /\ \ / /\ \ GO--------
Division of Kinesiology / / \ / \ \ GOPHERS!!!
Human Movement Research Lab Y " Y " Y " ----------

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