The finite element (FE) method has been used in orthopaedic biomechanics to investigate the fixation role of different design parameters in total knee replacement (TKA). Previous FE model studies used 2D, axisymmetric and 3D models to represent the geometry while neglecting many essential features. They simulated the bone-implant interface as frictionless, perfectly bonded or with idealized Coulomb’s friction model. The model of screws and posts have also been neglected altogether or inadequately considered in these studies. To overcome these limitations, the objective of the present study was set to develop a detailed 3D FE model of the knee bone-implant structure including all the interacting components in an immediate postoperative period without bony ingrowth to predict the micromotion at the bone-implant interface and stress distribution within the bone and the polyethylene insert.