Pairwise strength relationships of cortical and cancellous bone in human femur: an autopsy study

To analyze the mechanical properties of cortical and cancellous bone in the femur and relate them to bone mineral, we retrieved 14 pairs of femurs from elderly subjects at autopsy. Bone mineral was measured by quantitative single-energy computed tomography. Significant associations were found between two types of cortical bone mechanical tests, three-point bending and pull-out of screw, one performed on the right and the other on the left femur. Similarly, pairwise associations were found between the mechanical tests of cancellous bone, punch and cube compression, one performed on the right and the other on the left femur. Also, all mechanical tests correlated with bone mineral as determined by quantitative single-energy computed tomography. In general, bone mass measures correlated better with bone strength than did bone density measures. However, the cortical and cancellous bone mechanical properties were not interrelated, which suggests a separate regulation of the strength of these two types of bone. Bone mineral may not only have importance for the occurrence of fractures; it should be considered as an important factor in the fixation of fragile bone.