Holding power of the 4.5 mm AO/ASIF cortex screw in cortical bone in relation to bone mineral.

To obtain basic data about the holding power of a 4.5 mm AO/ASIF cortex screw in cortical bone in relation to bone mineral as expressed by densitometric methods, uniaxial pull-out tests were performed on 14 human cadaver femurs. The mechanical parameters were correlated with bone mineral which was assessed by quantitative computed tomography (QCT) and dual energy X-ray absorptiometry (DXA). High correlations were found between the QCT mass, the DXA density and content values and the holding power of the screw. The QCT density values, expressing the physical density of the bone, did not correlate similarly well.