Disclosed herein are arthroplasty jigs each having a living hinge that allows the jigs to be snap-fitted on and off bone. The jigs each have a flexible portion and base portion. The flexible portion is adapted to move toward and away from the base portion as the guides are snap-fitted on and off bone. The jigs may include cutting slots for receipt of cutting instrument to resect the bone and/or guide holes to aid in securing the jig to the bone. The living hinge of the jigs is defined by one or more recesses in the body of the jigs.