Restoration of femoral offset during hip replacement

Abstract

Restoration of femoral offset is an important part of total hip arthoplasty. Since radiographs showeing the femur at a sufficient degree of internal rotation to allow direct measurement of femoral offset are not usually available, templates of the prothesis at 25 and 45 degrees of rotation are created. Radiographs of 20 cadaver femurs with a mean offset of 44 +- 5 mm (r 36-56) were then obtained at different degrees of rotation. Simple guidelines to indicate the correct template for each projection of the femur were found. The system could be used to select a prothesis with correct offset using radiographs obtained at angles of rotation between 20 degrees internally ad 40 degrees externally.