1. A method for providing an overlay image of an implant using a mobile computing device, the implant including radio-opaque internal markers adjacent to and defining edges of the implant, the mobile computing device storing a library of 3-D implant data including 3-D positions of the radio-opaque internal markers in 3-D space, the method comprising: capturing an image of an imaging display device screen, the image including the implant and at least two of the radio-opaque internal markers being visible as fiducial markers within the captured image, the fiducial markers being 2-D positions of the radio-opaque internal markers in a 2-D plane; estimating a pose of the implant based on the relationship between the 2-D positions of the radio-opaque internal markers and the 3-D positions of the radio-opaque internal markers; retrieving or generating a 3-D model image of the implant at the determined pose using the 3-D implant data; and overlaying the 3-D model image onto the captured image, wherein the 3-D model image is provided at the estimated pose over the implant.