Methods for testing the strength of cancellous bone and tested method effects on cortical bone in the ovariectomized rat

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references: p. 111-121.Issued also on microfiche from Lange Micrographics.In this study, two mechanical testing procedures were developed to test the strength of cancellous bone from the proximal tibia of the rat, the "punch method" and the "whole slice method". These were used to quantify the effect of ovariectomy on rat bone tissue. For the "punch method", a compressive load was applied through two 3 mm diameter, axially aligned, cylindrical, plano-parallel platens which contact only the central cancellous region of the bone. In these tests, the cortical shell remained attached to the specimen but it was not loaded directly. For "whole slice method", the load was applied through two piano-parallel surfaces that completely support and load the entirety of the proximal and distal aspects of the specimen. For the "punch method" there was 59.9% decrease in the maximum force, a 57.9% decrease in the stiffness, a 60.0% decrease in the maximum stress, and a 58.3% decrease in the elastic modulus for the OVX group compared to the Sham group. For the "whole slice method" there was 31.6% decrease in the maximum force, a 24.4% decrease in the stiffness, a 33.2% decrease in the maximum stress, and a 28. 1 % decrease in the elastic modulus for the OVX group compared to the Sham group. Also, in this study, a comparison was made of the effect of two testing methods, torsion and three-point bending, on the mechanical strength of the rat femur and the changes in strength due to ovariectomy. From these tests, little change in cortical bone properties for the OVX rats compared to the Sham rats was detected for the two testing methods