[Radiometry of epiphyseolysis capitis femoris. A comparison of conventional roentgen study with axial computerized tomography].

CT scans are proposed for the measurement of tibial, femoral and humeral torsion. The value of computerised tomography in the evaluation of slipped capital epiphysis is yet not discussed. Conventional roentgenographic studies have shown that the capital femoral epiphysis slips by rotating backwards. In a study of 5 cases with a right site slip of the capital femoral epiphysis of different extent a comparison of conventional radiography with CT-scan was undertaken. True lateral films of both hips were obtained at the same time when CT scan of the femoral head and the condylar region of the femur were performed. The optimal site of cross-sectioning the femoral head lies in its center. Both measurements of the epiphysial torsion vary more ore less. This is believed to be related to the different plans in which the upper femoral end is projected in conventional radiography and CT-scan. Both angles of epiphysial torsion are geometrically related. A formula is given for mathematical transfer. Only by marked epiphysial displacement both angles vary to a greater extend. CT scan is suggested to be of certain value in the preoperative evaluation in heavy slips.