Abstract
The purpose of this study was to develop a method for evaluation of the three-dimensional (3D) alignment and position of the artificial knee joint using a biplanar slot radiography (SR) system and 3D models. A SR system uses collimated fan beam x-rays synchronized with the movement of a flat-panel detector. This system allows to obtain a full length x-ray image of the body with reduced dose and smaller image distortion compared with conventional x-ray systems. The biplanar SR system used a rotation table positioned at 0 deg and 60 deg relative to the optical axis of an X-ray source. Camera calibration was performed using an acrylic frame with 72 radiopaque markers. The femoral and tibial components of a total knee replacement system were immobilized and imaged using the biplanar SR system. Then, the femoral component was installed on a sawbone femur and imaged again. The 3D positions of the components and femur were recovered using an interactive 2D to 3D image registration method. Overall, the largest estimation errors were within 1 mm in translation and 1 deg in rotation, demonstrating that this method has an adequate accuracy for the clinical usage.
