1. A method of fabricating a customized patient-specific guide block, the method comprising: generating a image of a patient's bony anatomy and an implanted prosthetic component secured to the patient's bony anatomy, identifying landmarks on the patient's bony anatomy and the prosthetic component, selecting a revision surgical instrument based the image and the landmarks, and manufacturing the customized patient-specific guide block including a customized prosthesis-specific negative contour shaped to match a corresponding contour of the implanted prosthetic component, the customized prosthesis-specific negative contour includes a concave surface shaped to match a convex surface of the corresponding contour of the implanted prosthetic component.