EXAMINATION OF SEVERAL TECHNIQUES FOR PREDICTING TRABECULAR ELASTIC-MODULUS AND ULTIMATE STRENGTH IN THE HUMAN LUMBAR SPINE

Parameters quantifying architecture changes are needed to characterize trabecular bone strength. Trabecular elastic modulus and ultimate strength in the human lumbar spine were predicted by using several techniques. Elastic modulus was best predicted with apparent density, ash density, ultrasonic velocity, computed tomography number, and histomorphological parameters. The ultimate strength was best predicted with apparent density, ultrasonic velocity, or histomorphological parameters. Based on the clinical acceptance of dual-photon absorptiometry as a measure of bone mass of the axial skeleton, the relatively poor predictive value of bone mineral content by dual-photon absorptiometry was not expected. However, since dual-photon absorptiometry integrates the attenuation through the entire cross-section of the vertebra, this technique would not be capable of predicting mechanical properties of trabecular bone alone. The measurement of computed tomography number at the position at which the specimen was cut to measure the mechanical properties was understandably a better predictor. As expected, little predictive power is obtained by measuring the Ca, P, or Ca/P ratio, since the range of chemical composition of bone is very narrow.