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View Full Version : Re: Tendon gripping tensile testing....techniques?



jdesjardins50
11-23-1999, 01:25 AM
In response to the Tendon gripping question:

At the Johns Hopkins University Biomechanics Lab, we have had
the opportunity to develop a novel Cryo-clamp design that has worked
very well for us and is relatively inexpensive as compared to liquid
Nitrogen cooling.

The design consists of machining up two thin aluminium plates
(1/4 to 1/8 inch thick) and putting groves on the inside
faces. We used V shaped groves that fit into one another with a depth of
about 1/8 inch. Not too sharp or you can cut the ligament. Then using 4
bolts tighten the ligament between the plates only ever so slightly. This
is not what holds the ligament, so don't tighten it very much at all.
Then, take a small block of dry ice, and place it one one of the outside
faces of the clamp. We designed some small spring loaded plastic
containers that both held the ice in place, insulated it, and pressed it
against the face of the clamp. That'a all there is to it. We had one
end of the clamp with a hinge joint so that we could attach it to the
actuator, but any interface will do. The ice block (1inch x 0.5 inch x
inch lasted about 15minutes and then we just put another in. The frozen
clamp could hold more than 5000N, but we never did test it to failure.
Once the clamp unfroze and the ligament just slipped right out, but that
was our fault. The freezing never had any bad effects on the ligament and
we were always very happy with the design. You could use muscle as well
as ligament in the clamp, and aside from the small amount of extra weight
that the clamp added to the system, it was perfect.
Try it out, I highly recommend using dry ice, and the left overs are great
for the grad student parties.
It cost us about 50 cents a pound and we usually got 10 pounds for a
complete day of testing. We cut it into blocks using a regular band saw,
but watch out that you give the band saw a rest every minute or so, of you
will freeze the blade and it will fracture.

We used these clamps for a number of experiments to hold the quadriceps
during physiologic loading experiments and this work is published in the
following references:

J.D. Des Jardins, B.A. MacWilliams, D.R. Wilson, E.Y.S. Chao, The In-Vitro
Assessment of Knee Joint Kinematics Under Physiologic Loading. Proceedings of
the 43rd Annual Meeting of the ORS, February 9-13, 1997, San Francisco,
California.

B.A. MacWilliams, J.D. Des Jardins, D.R. Wilson, J. Romero, E.Y.S. Chao, A
Repeatable Alignment Method and Local Coordinate Description For Knee Joint
Testing and Kinematic Measurement. Journal of Biomechanics, Volume 31, Number
10, pp. 946-950, 1998.

J.J. Elias, J.D. DesJardins, A.F. Faust, S.A. Lietman, E.Y.S. Chao, Size and
Position of a Single Condyle Allograft Influence Knee Kinematics. Journal of
Orthopaedic Research, Vol. 17, No. 4, 1999.

B.A. MacWilliams, D.R. Wilson, J.D. DesJardins, J. Romero, E.Y.S. Chao,
Hamstrings Cocontraction Affects Knee Kinematics and Kinetics during
Weightbearing Flexion. Journal of Orthopaedic Research, Accepted for
Publication, 1999.

A.M. Bevilacqua, J.D. Des Jardins, D.R. Heekin, A.F. Faust, J.J. Elias, E.Y.S.
Chao, The Effect of Tibial Tray Malrotation on Knee Kinemaitcs in Total Knee
Arthroplasty. Journal of Arthroplasty, Submitted for Publication, 1998.

D.R. Wilson, B.A. MacWilliams, J.D. Des Jardins, E.Y.S. Chao, In-Vitro
Simulation of Knee Joint Kinematics. Proceedings of the 1996 ASME Mechanics and
Materials Conference, June 12-14, 1996, Baltimore, Maryland.

D.R. Wilson, B.A. MacWilliams, J.D. Des Jardins, E.Y.S. Chao, Effects of
Hamstrings CoContraction on Tibial Position. Proceedings of the 43rd Annual
Meeting of the ORS, February 9-13, 1997, San Francisco, California.

J.D. Des Jardins, J.J. Elias, A.F. Fuast, P. Shih, F.J. Frassica, E.Y.S. Chao,
Influence of Allograft Size and Position on Knee Kinematics. Proceedings of the
Annual Meeting of the International Society on Limb Salvage (ISOLS), September
10-12, 1997, New York, New York.

A.M. Bevilacqua, J.D. Des Jardins, D.R. Heekin, A.F. Faust, J.J. Elias, S.
Yang, P.Rullkoetter, E.Y.S. Chao, The Effect of Tibial Tray Malrotation on Knee
Kinemaitcs in Total Knee Arthroplasty Proceedings of the 10th Annual Symposium
of the International Society for Technology in Arthoplasty (ISTA), September
25-27, 1997, San Diego, California.

A.M. Bevilacqua, J.D. Des Jardins, D.R. Heekin, A.F. Faust, J.J. Elias, S.
Yang, P. Rullkoetter, E.Y.S. Chao, The Effect of Tibial Tray Malrotation on
Knee
Kinemaitcs in Total Knee Arthroplasty. Proceedings of the Meeting of the
Society
of Military Orthopaedic Surgeons (SOMOS), October 6-10, 1997, Lake Placid, New
York.

A.M. Bevilacqua, J.D. Des Jardins, D.R. Heekin, A.F. Faust, J.J. Elias, P.
Rullkoetter, E.Y.S. Chao, The Effect of Tibial Tray Malrotation on Knee
Kinemaitcs in Total Knee Arthroplasty. Proceedings of the 31st Annual Residents
Conference of the American Orthopaedic Association (AOA), February 19-22, 1998,
Sacramento, California.

J.D. Des Jardins, A.F. Faust, J.J. Elias, S. Lietman, E.Y.S. Chao, The
Influence
of Segmental Femoral Allograft Size and Position on Knee Kinematics.
Proceedings
of the 44rd Annual Meeting of the ORS, March 16-19, 1998, New Orleans,
Lousiana.


J.D. Des Jardins, B.A. MacWilliams, D.R. Wilson, S. Kato, J.J. Elias, E.Y.S.
Chao, The Kinematic Effects of Hamstring Cocontraction on Intact and ACL
Deficient Knees. Proceedings of the 44rd Annual Meeting of the ORS, March
16-19,
1998, New Orleans, Lousiana.

A.M. Bevilacqua, J.D. Des Jardins, D.R. Heekin, A.F. Faust, J.J. Elias, E.Y.S.
Chao, The Effect of Tibial Tray Malrotation on Knee Kinemaitcs in Total Knee
Arthroplasty. Proceedings of the 44rd Annual Meeting of the ORS, March 16-19,
1998, New Orleans, Lousiana.

Good luck, and if you need any drawings or anything like that, please
contact me at the above email.

John DesJardins
At 05:06 PM 11/19/99 -0500, Jeffrey Cartmell wrote:
>Hello,
>
>As part of my research project, I am planning to do mechanical testing
>of rabbit patellar tendon specimens. I would like to do testing on the
>tendon itself (without the bone ends attached), but may consider using a
>bone-tendon complex. I am having difficulty achieving adequate gripping
>of the samples on our Instron mechanical tester, and was wondering if
>this group could be of help. A number of protocols utilizing custom
>clamps and/or potting methods appear in the literature, specifically
>utilizing liquid nitrogen.
>
>I was wondering if anyone has information on:
>1. What are the best methods for gripping the specimens if the bone
>attachmenst are left intact ?
>2. What are the best methods for gripping the specimens if the bone
>attachments are removed ?
>3. Are liquid nitrogen cooled grips for tissue esting comercially
>available, and if so who is the supplier ?
>4. Are there other methods of gripping tendon (either with or without
>the bone attachments) which you can recommend?
>
>I will be happy to list a summary of the responses to this query. Thank
>you in advance for your help.
>
>- J. Cartmell
>
>.
>
>*************************************
>Jeffrey S. Cartmell
>Ph.D. Candidate
>Biomedical Engineering
>Rutgers University and UMDNJ
>-------------------------------------
>email: cartmejs@umdnj.edu
>phone: (732) 235-6954
>fax: (732) 235-6002
>*************************************
>
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**************************************************
John DesJardins, M.S.
Research Associate
Clemson University
Department of Bioengineering
401 Rhodes Research Building, Room 503
Clemson, South Carolina 29634-0905
Office: (864) 656-4178
Lab: (864) 656-4199
Fax: (864) 656-4466
email: jdesjar@clemson.edu
**************************************************

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