Micro-cantilever bending for elastic modulus measurements of a single trabecula in cancellous bone

Abstract

Mechanical tests performed on small bone specimens such a single trabecula remain challenging because their isolation, fixation, and precise loading are complicated. Hence, we describe a novel experimental method to measure the elastic properties of a single trabecula using micro-cantilever bending (MCB) testing. The method does not require specimens to be completely separated from the cancellous bone, and the specimen can be easily fixed during the test. In total, 10 trabecular specimens taken from the proximal epiphysis of an adult bovine femur were used in the present study. Measurements were conducted using a small testing device comprising a 1-axial stage, load cell, optical microscope, and small plate with a taper bore for applying load at the edge of the specimen. Each specimen was positioned at the edge of the bore and was deformed by displacing the stage. The deflection of the specimen was observed by optical microscopy. The elastic modulus of the specimen was calculated on the basis of the force-deflection relationship, assuming that the shape of the specimen was a vertical circular cylinder. As a result, an average elastic modulus of 9.1±5.4GPa was obtained for a single trabecula, including the values in literature. Thus, the MCB test is a novel simple method for biomechanical analysis of a single trabecula.

Keywords: Cancellous bone; Elastic modulus; Mechanical test; Single trabecula.