The patient specific glenoid guide comprises a guide feature, at least three arms having a first end coupled with the guide feature and a second end disposed away from the guide feature, at least three peripheral pegs, each peripheral peg extending from the second end of a corresponding arm and comprising an engagement surface configured to engage the scapula of the patient, and a strut extending laterally from the guide feature, the strut comprising a positioning opening that is provided to be positioned in use along a supero-inferior axis of a glenoid component to be implanted with reference to the guide.
