A patient-specific unicompartmental tibial guide (100) has a patient-specific body (102) with an inner surface (104). The inner surface is preoperatively configured to nestingly conform and mate in only one position with an anterior portion and a proximal portion of a tibial bone (70) of a specific patient. The tibial guide includes a vertical resection channel (136) having a variable width preoperatively configured for guiding a vertical resection through the proximal portion of the tibial bone.
