Automatic computation of reposition parameters of fractured long bones based on CT-analysis

First of all we segment, label and reconstruct the relevant fragments of the fractured bone in the preoperative computed tomography. After that, we use a voting mechanism to compute bone shaft axis and circumference of the long bone fragments, and separate the fractured surface. This Houghlike method is based on the fact, that most of the surface normals of the superficies surface (periosteum) are nearly perpendicular to the shaft axis. The axes are an important feature for calculating an initial reposition solution (constraining 4 dof). After these processing steps, it is possible to calculate the relative transformations between corresponding fragments by using wellknown surface registration techniques, like an adapted ICP-algorithm.