Ball element temporarily used for determination of position of hip replacement unit, comprising adjustable components

摘要

For a first implant or a replacement of a worn out unit the final position has to be determined with a test element. The test element is assembled of a calotte-shaped head (1) with a cylindrical inner space accommodating a cylindrical element (3) with a conical inner space. A movable spring supported conical element (2, 4) is positioned inside the space. A scale printed on the outer surface of the cone (4) can be used for a determination of the length of the collum femoris.