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Barker, Dan
04-15-1997, 03:53 AM
Thank-you to all those to replied.

The main suggestion to clamp ligaments, without a bone-ligamanet-bone
complex, for mechanical testing was liquid nitrogen. This technique may not
be suitable for small specimens however.

Joel M. Bach wrote
" For a reference on the cryogenic clamps check Riemersa, DJ; Schamhardt,
HC; The Cryo-Jaw: A clamp designed for in vitro theology studies of horse
digital flexor tendon, Journal of Biomechanics, vol. 15, no. 8, 1982, pp.
619-20. There may also be a more recent reference by Neil Sharkey from UC
Davis.
I used these clamps for applying quadriceps and hamstrings loads across
the knee. They worked extremely well but unless you control the flow of
nitrogen very well you can freeze the tissue some distance away from the
end of the clamp. For an application such as yours this may be too large a
potential limitation."

Dr Eric Powell wrote
"We used this technique to test the failure loads of repaired tendons:

Powell et al (1989). Non-suture repair of tendons. J Biomed Eng,
vol 11, pages 215-218.

there is a diagram in the paper that will give you an idea of the
construction of such cramps. The whole thing would have to be scaled
down for your purposes, and another thing to do would be to measure
the temperature of the tissue between the two clamps. If it was
cooled down too much it might effect your results."

Douglas C. Moore wrote
"Try doing a literature search on N.A. Sharkey. He did some tendon or
ligament work a few years ago in which he used freeze clamps."

Paul McArthur wrote
"As far as I am aware the liquid nitrogen filled clamp is suitable for
tendon testing or knee ligaments but I am not sure it will be
suitable for small tissue volumes. One reason could be that liquid N2
will probably freeze your specimen or at least produce temperature
variation within the sample."

Helio Schechtman wrote
"I have tested extensively tendons and for long testing periods. I found
that
a self-tightening clamp did the job, especially if the cross-sectional area
was small. The self-tightening clamp does not work for large cross-sectional
areas. There were a few people that used a liquid nitrogen clamp (cryo jaw)
for testing ligaments and even tendons. One of the references is Riemersma
D.J. & Schamhaedt H.C. - The cryo jaw, a clamp designed for in vitro
rheology studies of horse digital flexor tendons - J. Biomechanics, vol. 15
(1982), 619-620. As far as I remember, although it says tendon, due to the
anatomy of horses, in fact, it is a ligament as the muscle is inexistent,
i.e. bone-ligament-bone. I would not try the cryo-jaw, I believe that
freezing will modify the properties of the ligament and the interface zone
between the frozen specimen and the fresh specimen might be a weak point.
This would cause the ligament to fail always at this interface."

Con Hrysomallis wrote
"In the following reference, liquid nitrogen was utilised as part of the
clamping technique:

Liggins et al.,1992. Technique for the application of physiological
loading to soft tissue in vitro. J. Biomed. Eng. 1992:14:440-441."

In regards to ultrasonic techniques

Helio Schechtman suggested
Mason P. - the viscoelasticity and structure of keratin and collagen -
Kolloid z. z. polymere, vol. 202 (1965), 139-147

Mason P. & Unsworth J. - viscoelasticity and structure of fibrous proteins.
III-low frequency dynamic behaviour of native and crosslinked tendon -
Kolloid z. z. polymere, vol. 249 (1971), 1101-1106

Once again, thankyou for the information.

Dan Barker (sbarkds@rgh.sa.gov.au)
Research Engineer
Repatriation General Hospital
Division of Orthopaedic Surgery
Daws Rd. Daw Park 5041 S.A.
Australia
Fax: 61 8 8374 0712
Tel: 61 8 8275 1107