1. A method of generating a patient-specific bone shell representative of at least a portion of a patient's bone in its current state, the method comprising: imaging at least a portion of a patient's anatomy to create a plurality of 2D image slices of the patient's anatomy taken orthogonal to an axis extending through the patient's anatomy, where each of the plurality of 2D image slices includes a bone segment comprising an enclosed boundary corresponding to an exterior of the patient's bone; constructing a 3D image bone shell of at least the portion of the patient's bone for which the plurality of 2D image slices of the patient's bone were taken, where the construction of the 3D image bone shell includes using software to recognize the enclosed boundary of each bone segment by using a template 3D image bone shell that is not patient specific, and where the 3D image bone shell depicts a current state of the patient's bone.