How to Correct Increased Anteversion of the Femoral Neck during THR

Abstract

In the great majority of the cases the “Anteversion Angle” (AVA) is in the normal range (10-20°) and on insertion the femoral stem follows automatically the direction of the femoral neck. There are basically 5 means of correcting an increased AVA: 1) The smaller the diameter of the endoprosthetic stem and the more its cross-section is circular the easier it is to modify the rotational position. 2) The lower the resection of the femoral neck the greater the freedom of correction of the anteversion. 3) A custom-made femoral endoprosthesis. 4) A non-cemented endoprosthesis with a stem circular in cross section - such as the conical stem of Wagner - can easily be positioned in a great variety of rotational positions. 5) To correct an AVA of the femur of more than 45 degrees an inter- or sub-trochanteric derotational osteotomy of the femur is indicated. With this not only is the AVA corrected but also the greater trochanter is brought from its posterior position to a more lateral one and the functional lever arm of the abductors is lengthened. To stabilize the osteotomy the use of a femoral endo-prosthesis with a non-cemented stem which is stable in rotation all along its length is recommended.