1. A method of electronically reconstructing cartilage in a patient's diseased or damaged joint, which method comprises: (a) obtaining a volumetric representation of cartilage of said patient's diseased or damaged joint in which said volumetric representation demonstrates normal and defective cartilage of said patient's diseased or damaged joint; (b) identifying a volume of interest including a cartilage defect associated with the patient's diseased or damaged joint, the cartilage defect being surrounded by normal cartilage; (c) estimating depth of lost cartilage tissue of the cartilage defect relative to expected cartilage tissue without the cartilage defect, based on the normal cartilage surrounding the cartilage defect; and (d) electronically reconstructing an estimated normal cartilage surface in the volume of interest, wherein the cartilage defect is eliminated based on the estimated depth of the lost cartilage tissue.