[Stability of human bone cortex following various preservation and sterilization methods].

In a biomechanical study we evaluated the stability of human femurs. In order to document the inter- and intraindividual differences in bending stability, and the changes in breaking strength after different storing and sterilizing procedures, we tested 200 bony blocks, which were harvested from the femurs of 5 multiorgan donors. The bending tests were performed with a material testing machine (ZWICK) under standardized conditions. The bone blocks we randomized into five different treatment groups (-25 degrees C deep freezing, steam sterilization, lyophilization, lyophilization + gamma irradiation, lyophilization + gamma-irradiation in argon). The statistical analysis was performed by a multivariant analysis. Our results revealed significant differences concerning breaking strength among different femurs of the 5 multiorgan donors, and a significant difference concerning stability in different areas of the same femur. Further on we found a significant difference with regard to the treatment modalities of the five groups. Compared to the control group (-25 degrees C deep freezing), we documented a decrease of 8.7% after steam sterilization, an increase of 18.9% after lyophilization, a decrease of 1.7% after lyophilization + gamma-irradiation, and an increase of 3.4% after lyophilization + gamma-irradiation in argon.