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

Area of Science:

• Orthopedic Biomechanics
• Materials Science

Background:

• Human femur biomechanical properties are crucial for orthopedic applications.
• Understanding inter- and intra-individual variations in bone stability is essential.
• The impact of various storage and sterilization methods on bone strength requires detailed investigation.

Purpose of the Study:

• To evaluate the bending stability and breaking strength of human femurs.
• To document inter- and intra-individual differences in femur biomechanics.
• To assess the effects of different storage and sterilization techniques on bone strength.

Main Methods:

• Biomechanical testing of 200 bony blocks from 5 multiorgan donors using a material testing machine.
• Randomization of bone blocks into five treatment groups: deep freezing, steam sterilization, lyophilization, lyophilization + gamma irradiation, and lyophilization + gamma irradiation in argon.
• Statistical analysis using multivariate analysis to compare results.

Main Results:

• Significant differences in breaking strength were observed among femurs from different donors and within different areas of the same femur.
• Steam sterilization decreased breaking strength by 8.7% compared to deep freezing.
• Lyophilization increased breaking strength by 18.9%, while lyophilization with gamma irradiation showed a slight decrease (1.7%) or increase (3.4%) depending on argon presence.

Conclusions:

• Human femur biomechanical stability exhibits considerable inter- and intra-individual variability.
• Lyophilization appears to enhance femur breaking strength, whereas steam sterilization diminishes it.
• Specific storage and sterilization protocols significantly alter the mechanical properties of human femur bone blocks.