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Smit, Th.h. Kft
01-10-1997, 03:42 AM
Dear subscribers,

some time ago I posted the following message:

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Subject: tissue fixation and mechanical testing

Dear list subscribers,

We are doing an animal study on the fixation of implants in bone. We are
interested both in histology and in the mechanical fixation strength, but
we have a problem in determining both aspects in the same animal. For
good histology, we need to fix the material as soon as possible after
obduction. At the moment, we do that in 70% alcohol. However, we have
serious concerns about changes in the mechanical properties of the
tissues (and consequently in the fixation strength) due to this. In
particular, we are concerned about the mechanical property changes in
cement, fibrous tissue and bone. We could not find studies addressing
this particular question, and therefore would like to put the following
questions on the net:

1. Does anyone have information on the mechanical changes of the cement,
fibrous tissue and bone due to fixation in alcohol?
2. Does anyone have a suggestion for an alternative fixation method,
especially one that would not (or hardly) affect the mechanical
properties?

Obviously, we also considered the possibility of sawing bone and implant
first and a fixation afterwards, but sawing several slices through an
implant takes several hours, and our histology department is most
suspicious about the quality of histology if we would do it like that.
Maybe there also are suggestions how to reassure these people, e.g. by
good examples from elsewhere.

Many thanks in advance,

Theo Smit
University Hospital Vrije Universiteit
Amsterdam, the Netherlands
e-mail: th.smit@azvu.nl
______________


and I received the following reactions (summarised):


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From: Jose Luis Peris Serra[SMTP:jlperis@ibv.upv.es]

Dear Dr. Smit,

We had similar problems working on fracture healing in rabbits and we
decided to use two different groups: a) mechanical tests and b)
histomorphometry. Probably this choice was not the cheapest one but it
worked well.
I would be very grateful if you could send me the information about
this subject that you collect.

Thanks in advance.

Jose L. Peris
Orthopaedic Biomechanics
Instituto de Biomecanica de Valencia (IBV)
PO Box 199
46980 Paterna (Valencia)
SPAIN
Phone: +34 6 1318355
Fax: +34 6 1318016
e-mail: jlperis@ibv.upv.es
_________



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From: KHAYES[SMTP:KHAYES@CMSA.gmr.com]
***********************
From: Hayes, Kevin W.
(810) 986-2504

Subject: tissue fixation and mechanical testing

Theo,

You sent a message to the Bio Mech list about fixation of bone and its
properties. Clemson University in Clemson, South Carolina, USA has done
a
lot of work with hard tissue implants and bone cement in animal models
over
the years. You might want to contact Linda Jenkins, the Histologist
there
as a starting point. She might be able to help you.

I don't have her email address but you should be able to reach her
through
Nancy Looney at (864) 656-5556. Nancy should be able to connect her to
Linda or give you an email address for her. I hope this helps.


Sincerely,

Kevin Hayes, M.S.
Clemson Bioengineering '95

Kevin W. Hayes
Delphi Interior and Lighting Systems-Contracted through Altair Eng.
(810) 986-2504 (8) 226-2504
khayes@cmsa.gmr.com
________



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From: Carl DePaula[SMTP:depaula@UMDNJ.EDU]


i have mechanical test results of bone tissue treated in alcohol

after treating the bone in alcohol the mechanical properties of the
tissue increase. the elastic modulus goes up along with the ultimate
strength. it gives a similar result to testing dry bone tissue.

alex


C. Alex Depaula
Doctoral Candidate
lab: 908 235-5755
fax: 908 235-4030
email: depaula@umdnj.edu
http://www2.umdnj.edu/~depaula/
Family and friends are what make life great

_______





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From: brian[SMTP:brian@gibbon.anat.sunysb.edu]
Subject: Effect of alcohol on bone

Theo,

I don't know about the effects of alcohol off the top of my head,
but
here are some references that may help you find the answer:


Sedlin, E.D. and C. Hirsch (1996) Factors affecting the determination of
the
physical properties of femoral cortical bone. Acta orthop Scand
37:29-48.

Sonstegard, D.A. & L.S. Matthews (1977) Mechanical property dependence on

storage technique and local of knee joint trabeculae. Trans. ORS 2:283.


Best of luck!


Brian


Brian G. Richmond
Doctoral Program in Anthropological Sciences
State University of New York at Stony Brook
Stony Brook, NY 11794-4364
_______



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From: Melinda Harman
Subject: bone cement in alcohol

..summarised poster text; see next response...

..The purpose of this study was to quantify processing artifacts that
accumulated over time as bone cement was exposed to chemicals used in
routine histological specimen preparation. This information is necessary
to insure accurate interpretation of cement mantle characteristics
observed after implant retrieval and is useful for choosing appropriate
fixation, dehydration, and embedding media...

..Both structural and mechanical differences in the cement specimens
were observed. Statistical analysis with post-hoc multiple comparisons
(ANOVA, Student-Newman-Keuls test) showed that the type of fixative,
dehydrant, or embedding resin used and length of time in solution were
significant factors in the compressive strength, weight and volume of the
bone cement specimens (p