A NEW METHOD OF COMPARATIVE BONE STRENGTH MEASUREMENT

Most investigations of the material properties of bone have been conce rned with the measurement of absolute values for various mechanical pa rameters. irt can be necessary, however, to produce test samples with similar mechanical properties in order to assess the effect on these p roperties of particular treatments. Absolute values for these properti es mag not be as important ar any changes observed. We describe hen a new method whereby many bone test samples with very similar mechanical properties can be produced. If the femoral shaft at the diaphysis is cut in transverse section, it is possible to produce many similar shap ed rings of bone. We compared the material properties of 48 ring sampl es with 65 beam specimens. Both were tested in three-point bending. Gl obal estimates of coefficient of variation (CV) for each parameter wer e used to assess similarity within each group. All the rings had very similar ash weights (1.98%), thicknesses (1.97%), and diameters (< 0.0 1%). Values of load/deflection of the rings were more similar than the values of Young's modulus (E) for the beams (7.06 versus 9.9%), and t he maximum loads sustainable by the rings were more similar than the b ending strengths of the beams (5.7 versus 13.6%). The energy absorbed by the ring samples was more consistent than the beams (14.31 versus 3 4.41%). We suggest that there is improved similarity in mechanical cha racteristics within groups of samples produced in this manner than wit h more conventional sample configurations.