title: Synergetic effect of freeze-drying and gamma irradiation on the mechanical properties of human cancellous bone.
abstract: Freeze-drying and irradiation are common process used by tissue banks to preserve and sterilize bone allografts. Freeze dried irradiated bone is known to be more brittle. Whether bone brittleness is due to irradiation alone, temperature during irradiation or to a synergetic effect of the freeze-drying-irradiation process was not yet assessed. Using a left-right femoral head symmetry model, 822 compression tests were performed to assess the influence of sequences of a 25 kGy irradiation with and without freeze-drying compared to the unprocessed counterpart. Irradiation of frozen bone did not cause any significant reduction in ultimate strength, stiffness and work to failure. The addition of the freeze-drying process before or after irradiation resulted in a mean drop of 35 and 31% in ultimate strength, 14 and 37% in stiffness and 46 and 37% in work to failure. Unlike irradiation at room temperature, irradiation under dry ice of solvent-detergent treated bone seemed to have no detrimental effect on mechanical properties of cancellous bone. Freeze-drying bone without irradiation had no influence on mechanical parameters, but the addition of irradiation to the freeze-drying step or the reverse sequence showed a detrimental effect and supports the idea of a negative synergetic effect of both procedures. These findings may have important implications for bone banking.
authors: Orthopaedic Research Laboratory, Orthopaedic Department, Université Catholique de Louvain, Cliniques Universitaires St-Luc-2/P5, Av. Hippocrate 10, Brussels, Belgium. olivier.cornu@uclouvain.be
authors: Olivier
authors: O
authors: Cornu
authors: Jérome
authors: J
authors: Boquet
authors: Olivier
authors: O
authors: Nonclercq
authors: Pierre-Louis
authors: PL
authors: Docquier
authors: John
authors: J
authors: Van Tomme
authors: Christian
authors: C
authors: Delloye
authors: Xavier
authors: X
authors: Banse
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena / Q000528:radiation effects; D001842:Bone and Bones / Q000502:physiology* / Q000528:radiation effects*; D019245:Compressive Strength / Q000528:radiation effects; D004367:Dry Ice; D005612:Freeze Drying; D005720:Gamma Rays; D006801:Humans
chemical_list: D004367:Dry Ice