Influence of different methods of bone processing on bone mechanical properties

Introduction Bone graft is the best option to repair postsurgical bone defects. The biomaterial is highly adaptive, structurally dynamic, metabolically active and characterized by high strength. Standard preparation of grafts for implantation includes cleaning followed by deep freezing and sterilization. However, methods used for processing bone material and reagents can change the biomechanical properties of the bone. The purpose was to explore the effect of chemical purification and subsequent lyophilization on the mechanical strength of bone grafts in comparison with native fresh frozen bone. Material and methods Metaepiphyseal sections of a single level of one tibia of a single cattle were used to rule out the influence of the variable density of native bone obtained from different donors. The bone was cut into blocks with a hand saw. Three groups of samples formed depending on the processing method included freshly frozen native bone, bone purified by combined chemical and physical methods and bone purified by the same technique followed by lyophilization. Mechanical properties were measured by axial compression mode using a 1958U-10-1 strength machine. Statistical data analysis was performed using the Kolmogorov-Smirnov (K-S) test and the Lilliefors correction with statistical significance of differences assessed with one-way analysis of variance (One-Way ANOVA). Results The cross-sectional area of hand-made blocks was comparable. No decrease in bone strength below the baseline was recorded regardless of the method of bone processing. Purified bone blocks demonstrated maximum strength characteristics prior to lyophilization. The sample strength decreased after lyophilization and was higher as compared to freshly frozen native bone. No statistically significant differences in the maximum force applied and the cross-sectional area were recorded between groups of samples. Modulus of elasticity and relative deformation had statistically significant differences in the groups (p < 0.05). Conclusion Modern methods of bone processing were shown to maintain biomechanical properties of the bone and can be used in the form of bone blocks or chips and as a structural graft.