Computer aided evaluation of total hip prosthesis stability

Abstract

© 1998 Heldermann Verlag. To obtain a stable total hip prosthesis it is of crucial importance that a prosthesis is well positioned and well orientated. In order to evaluate the position and orientation of the prosthesis one must determine at least four angles from the postoperative radiograph of the operated hip: inclination of the cup, anteversion of the cup, anteversion of the femoral part and valgus of the femoral part. If the measurement of these angles is carried out by a human himself, some mistakes caused by subjectivity of the person may frequently occur as well as the fact that this information is not useful intraoperative, since the measurement of these angles is usually done after the operation, when there is no way to correct the position and orientation of the prosthesis without another operation. The aim of this paper is to create an algorithm and a program for computer aided evaluation of total hip prosthesis stability in order to gain the most objective and sufficiently fast information which could greatly help the surgeon during the operation, before closing the wound, to decide whether the prosthesis is stable or not.