1. A method of manufacturing an arthroplasty cutting guide, the method comprising: a) using a medical imaging machine to generate images of a patient joint bone selected for an arthroplasty procedure; b) transferring the images to a computer; c) identifying a target region in the images corresponding to a portion of the patient joint bone to undergo the arthroplasty procedure; d) using the computer to define first contour lines along the target region, the first contour lines extending along contours of an outer cartilage surface in an articular area of the target region; e) using the computer to define from the first contour lines a mating region of the arthroplasty cutting guide; f) converting the mating region into first production file data; g) using the computer to define second contour lines along the target region, the second contour lines extending along contours of an outer cortical bone surface in the articular area of the target region; h) using the computer to define from the second contour lines a resection plane of the arthroplasty cutting guide; i) converting the resection plane into second production file data; and j) transferring the first production file data and second production file data to an automated manufacturing machine that uses the first production file data and second production file data to manufacture the arthroplasty cutting guide to have the mating region and resection plane.