A computerized morphometric evaluation of x-ray films for preoperative planning of hip arthroplasty.

Methods for measuring metric size on radiograms constitute an instrument of proven utility. For example, when preoperatively evaluating hip arthroplasty the diameter of the medullary canal and the cervicodiaphyseal angle, must be measured in order to determine the center of rotation of the femoral head, and to establish the flare index of the diaphyseal canal. These results may be obtained by using a computer-controlled graphic table to place the coordinates for the areas of greater anatomical and physiological importance on the radiologic image. Thus, a calculation of distances, anatomical axes and angles is obtained immediately, accurately defining the morphometry of the joint. In this study, the anteroposterior preoperative radiographic views of 87 femurs in 84 patients were evaluated by this method. The values provided by the morphometric analysis were then related to sex, age and weight. The diaphyseal canal was classified by typology for the preoperative planning of hip arthroplasty.