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We have done some testing on both bone/tendon/bone preparations and
free tendons in tension. A free tendon is difficult to hold, but if you have
enough length it can be done. We manufactured small wedge action grips
with interdigitating involute teeth to hold the tendon. Try to avoid sharp
edges and hard corners. The total grip length was about 20 mm, and the
free length about 60 mm (the tissue was from dogs). We got most of our
failures in the mid substance of the tendon, but there was a significant
initial slip within the grips, which then settled down. An extensometer
across the gauge length gets around this problem.
For bone blocks, we usually embed them in PMMA and then drive a small
wire or pin through the PMMA/bone block. For bigger blocks we use
PMMA to embed in a metal container (square tube works well), and then
pin the lot before fixing the metal container to the grips.
We have not yet tried ice vice type systems, but we would like to in future
when we get the time ;-). All our equipment was made up in our lab here.
Rob.
--
Robert Day rob.day@nero.rph.health.wa.gov.au
Project Bioengineer ph +61 8 9224 3227
Royal Perth Hospital fax +61 8 9224 1138
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free tendons in tension. A free tendon is difficult to hold, but if you have
enough length it can be done. We manufactured small wedge action grips
with interdigitating involute teeth to hold the tendon. Try to avoid sharp
edges and hard corners. The total grip length was about 20 mm, and the
free length about 60 mm (the tissue was from dogs). We got most of our
failures in the mid substance of the tendon, but there was a significant
initial slip within the grips, which then settled down. An extensometer
across the gauge length gets around this problem.
For bone blocks, we usually embed them in PMMA and then drive a small
wire or pin through the PMMA/bone block. For bigger blocks we use
PMMA to embed in a metal container (square tube works well), and then
pin the lot before fixing the metal container to the grips.
We have not yet tried ice vice type systems, but we would like to in future
when we get the time ;-). All our equipment was made up in our lab here.
Rob.
--
Robert Day rob.day@nero.rph.health.wa.gov.au
Project Bioengineer ph +61 8 9224 3227
Royal Perth Hospital fax +61 8 9224 1138
---------------------------------------------------------------
To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------