A humeral cut guide system for a humeral head comprises: a bone-engagement member including a first patient-specific bone-engagement surface that is complementary and made to substantially mate and nest in only one position on a specific patient's humeral head; a registration member connected to the bone-engagement member including a second patient-specific bone engagement surface that is sized and made to substantially mate and nest in only one position with the specific patient's bicipital groove; a first protrusion extending from the registration member and having a first surgeon-engaging surface for manipulation by a surgeon; and a cut guide plate connected to and extending away from the registration member such that, upon the bone-engagement member mating and nesting with the specific patient's humeral head, the cut guide plate is spaced apart from the humeral head, wherein the cut guide plate defines an elongate slot.