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summ.: tissue fixation and mechanical testing

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  • summ.: tissue fixation and mechanical testing

    Dear subscribers,

    some time ago I posted the following message:

    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

    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

    and I received the following reactions (summarised):

    From: Jose Luis Peris Serra[]

    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)
    Phone: +34 6 1318355
    Fax: +34 6 1318016

    From: KHAYES[]
    From: Hayes, Kevin W.
    (810) 986-2504

    Subject: tissue fixation and mechanical testing


    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
    lot of work with hard tissue implants and bone cement in animal models
    the years. You might want to contact Linda Jenkins, the Histologist
    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
    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.


    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

    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.


    C. Alex Depaula
    Doctoral Candidate
    lab: 908 235-5755
    fax: 908 235-4030
    Family and friends are what make life great


    From: brian[]
    Subject: Effect of alcohol on bone


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

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

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

    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