The Effect of Orientation on Some Mechanical Properties of Femoral Cortical Specimens

Abstract

The material used consists of 140 samples of human femoral diaphyseal bone obtained in routine postmortem examinations from 12 adult subjects ranging from 30-74 years of age. Both sexes were included. Many of the specimens obtained were from patients who were bed-ridden during varying periods of time before death. The specimens, which were standardized in size, were taken from different parts of the bone. After preparation the specimens were stored in Ringer''s solution at -30[degree] C until tested. The specimens were then tested under bending in an Instron model tensile testing machine calibrated to an accuracy of [plus or minus] 5%. The specimens were tested like a free, simple beam. The maximum deformation, the residual deformation, and the energy dissipated in each cycle were measured. The stiffness of the cortical bone was closely related to the angles to which the bone was cut; it was less stiff as the angle increased in relation to the longitudinal axis of this shaft. The residual deformation and the energy dissipated are proportional and vary with the angle. The results are illustrated by graphs, presented in tabular form and there is a photograph of the specimen in the testing chamber. Eleven references are cited.