A bone preparation guide including a first patient-specific portion based on image data of a specific patient's bone and configured to match the patient's specific bone surface. A second patient-specific portion is based on image data of the specific patient's bone and configured to match the patient's specific bone surface. A patient-generic portion is configured to be a bone-facing portion supported by the first and the second patient-specific bone contacting members at a portion of the patient's bone surface not imaged during preparation of a preoperative plan.