1. An arthroplasty jig for assisting in the performance of an arthroplasty procedure associated with a patient surface including at least one of a bone surface and a cartilage surface, the jig comprising: a first side; a second side generally opposite the first side; and a mating surface in the first side and configured to matingly receive and contact at least a portion of the patient surface, wherein the first side is configured to be oriented towards the patient surface when the mating surface matingly receives and contacts the patient surface, wherein the mating surface is defined according to the following process steps: a) identifying a contour line associated with the patient surface as represented in a medical image; b) using a computer processing device, evaluating via an algorithm the adequacy of the contour line for defining a portion of the mating surface associated with the contour line; c) modifying the contour line if the contour line is deemed inadequate; and d) employing the modified contour line to define the portion of the mating surface associated with the contour line.