Importance of newly defined epiphyseal version in diagnosis and therapy of epiphysiolysis capitis femoris (additional data to epiphyseal dislocation and epiphyseal torsion)

: The displacement of the femoral epiphysis in epiphyseolysis capitis femoris is usually determined by measuring both the epiphysis-diaphysis angle (ED angle) in the plane of the dislocation and the epiphysis-torsion angle (ET angle) in the torsional plane. In this paper we define an epiphyseal version angle (EV angle) in the sagittal plane of the femur, calculate it trigonometrically and show it in diagrams and tables. The clinical application of the EV angle indicates that in cases of displacement with an ED angle of less than 135 degrees, absolute displacement is better shown than with the ET angle. Additionally, the EV angle improves our comprehension of the 3-D displacement due to the fact that, in the "Lauenstein" x-ray, the femur is increasingly projected more in a sagittal plane with increasing abduction. The essential correction using the Imhauser-osteotomy is also done in the sagittal plane. The ability of the orthopaedic surgeon to visualize the situation in three dimensions is also improved by this additional standard plane.