Abstract: A surgical instrument assembly configured to display a representation of the surgical instrument relative to a trajectory (e.g., a desired trajectory for drilling into an implant) based image data from an image sensor (e.g., a camera). For example, the surgical instrument assembly may be configured to determine a desired trajectory (e.g., a central axis of a distal hole of an intramedullary nail) based on X-ray image data representing at least one fiducial marker (e.g., an array of ArUco markers) and representing an anatomical structure and/or an implant. The surgical instrument assembly may in real time display a representation of the orientation and/or position of the surgical instrument (e.g., the orientation and position of a drill bit of the surgical instrument) in relation to the desired trajectory based on image sensor data that is generated based on an orientation of the at least one fiducial marker detected by an image sensor.