Effect of long-term preservation on the mechanical properties of cortical bone in goats.
OBJECTIVE
Bones used in mechanical studies are frequently harvested from human cadavers that have been embalmed in a buffered formaldehyde solution. It has been reported that formaldehyde fixation or freezing hardly affects the mechanical properties of bone after a storage period of several weeks. However, human cadaver bones are usually stored for longer periods of time before use. We therefore investigated the effects of long-term embalming or freezing on the mechanical properties of cortical bone.


METHODS
After 5 different storage periods (ranging from 0 to 12 months), goat femora and humeri were used to evaluate the effect of embalming and freezing on torsion, and on bending stiffness and strength. The effect on hardness and bone mineral density (BMD) was also evaluated.


RESULTS
Even after 1 year, no statistically significant differences could be found in stiffness, strength, and energy absorption when we compared embalmed or frozen bones to a fresh reference group. In addition, although we found no significant change in BMD, there appears to be a tendency to increasing hardness.


CONCLUSIONS
We found that there was no effect on the mechanical properties of bone after storage periods of 1 year. We conclude that embalmed or frozen bones can safely be used for mechanical testing, at least for storage periods of up to one year.
Department of Orthopedic Surgery, VU University Medical Center, Amsterdam, the Netherlands.
Emil H
EH
van Haaren
Babette C
BC
van der Zwaard
Albert J
AJ
van der Veen
Ide C
IC
Heyligers
Paul I J M
PI
Wuisman
Theo H
TH
Smit
D000818:Animals; D001696:Biomechanical Phenomena; D018586:Bone Banks; D015519:Bone Density; D016025:Bone Transplantation / Q000502:physiology; D001842:Bone and Bones / Q000378:metabolism / Q000502:physiology*; D002102:Cadaver; D015925:Cryopreservation; D006041:Goats; D006801:Humans; D013314:Stress, Mechanical; D013718:Tensile Strength; D013997:Time Factors; D016707:Tissue Fixation; D014021:Tissue Preservation / Q000379:methods