Bending stiffness of healing fractures can be calculated from quantitativecomputed tomography

This paper revisits the relationship between bone densitometry and fracture healing by using quantitative computed tomography (QCT) to assess bone den sity. In recent time the correlation between bone mineral density (BMD) and mechanical stability of healing bone has been investigated with the purpos e to predict mechanical properties of healing fractures-such as their loadi ng capability-from data which can be collected non-invasive. One goal is to obtain a functional dependency between data obtained from QCT and the mech anical properties. In this study the computation of the mechanical stabilit y of fractures from data obtained by QCT is proved to be reliable (r(2) = 0 .947 and P < 0.0001). As one result most dependencies between mechanical da ta and stiffness are not linear but quadratic (r(2) > 0.72, P < 0.0005). Th e only linear dependencies are found between the second polar moment of ine rtia (I-p), calculated from geometric midpoint and center of mass (r(2) = 0 .688, P = 0.0052 and r(2) = 0.677, P = 0.0010), and the average density (r( 2) = 0.836, P < 0.0001) versus bending stiffness. A functional dependency b etween bending stiffness and bone mineral content (BMC) of the fracture are a in the fracture gap can be provided. The data presented in this work has been computed by a new algorithm developed by the author for detecting the fracture area of minimal density automatically in three-dimensional data ob tained from QCT. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved .