G0200205 Micro Cantilever Bendingによる海綿骨骨梁単体の弾性率計測

Abstract

Cancellous bone has a three-dimensional network of single trabecula. It has been reported that the apparent elastic modulus of cancellous bone is much smaller than that of cortical bone and that the elastic modulus depends on the trabecular network. However, the mechanical properties of single trabecula are still unclear, because mechanical tests of single trabecula are challenging. This study aimed to develop an experimental method to measure the elastic properties of single trabecula that was 1 mm in length by micro cantilever bending. In the experiments, 10 single-trabecula specimens taken from the proximal epiphysis of a 2-year-old bovine femur were used. The tests were conducted using a small testing device that consisted of an acrylic plate for applying load to the specimen, a linear stage, and a load cell. The specimen was in contact with the edge of a taper bore drilled in the acrylic plate and was deformed by applying the displacement with the stage. The deflection of the specimen was observed by optical microscopy. A finite element model of the specimen was constructed from a micro-CT observation. The elastic modulus of the specimen was calculated from the force-deflection relation by finite element analysis. As a result, elastic modulus of single trabecula was 8.2 ± 3.3 GPa. There was no correlation between the elastic modulus and trabecular orientation in the femur. The study showed that the elastic modulus of single trabecula was much smaller than that of the cortical bone in bovine femoral diaphyses by proposed method.