Abstract: A computer-assisted implant positioning system is provided that includes a receiver; a memory operatively connected to the receiver and a processor. The processor is configured to receive preoperative patient-specific data, receive a 3D model of the subject implant, receive an intraoperative patient-specific 2D image of the target bone, register the 3D model of the subject implant to the intraoperative patient-specific 2D image and determine a best fit for the 3D model of the subject implant to the intraoperative patient-specific 2D image, register the 3D bone model of the target bone to the intraoperative patient-specific 2D image of the target bone and determine a best fit for the 3D bone model to the intraoperative patient-specific 2D image, determine an achieved 3D implant position based on the registered 3D model of the subject implant and the registered 3D bone model, and assess the achieved implant position relative to the preoperative patient-specific data.