A kit for making a glenoid prosthesis, the kit comprising: an articulating member having an articulation side and an opposing second side opposing the articulating side, in which the opposing second side includes a locking mechanism, and a plurality of bases, each of the plurality of bases having an articulating-member facing side and a glenoid attachment side, in which each of the plurality of glenoid attachment sides includes at least one glenoid attachment member (20, 22) extending outwardly and sized and shaped to extend into a patient's glenoid, in which the glenoid attachment member of one of the plurality of bases differs from the glenoid attachment member of at least one other of the plurality of bases, and in which each of the plurality of bases includes a locking mechanism sized and shaped to lock each of the plurality of bases to the articulating member, characterised in that the opposing second side of the articulating member includes a recess defined by first, second and third sidewalls with a lip at the top of each of the said sidewalls, the second sidewall being located opposite to the third sidewall and an opening being located opposite to the first sidewall which allows a selected base to be slid between the second and third sidewalls into the recess, the locking mechanism on the articulating member comprising a locking recess in each of the second and third sidewalls and the locking mechanism on the base comprising a pair of locking protrusions which are positioned so as to be received in the locking recesses in the side walls when the base is slid fully into the recess in the articulating member. an articulating member having an articulation side and an opposing second side opposing the articulating side, in which the opposing second side includes a locking mechanism, and a plurality of bases, each of the plurality of bases having an articulating-member facing side and a glenoid attachment side, in which each of the plurality of glenoid attachment sides includes at least one glenoid attachment member (20, 22) extending outwardly and sized and shaped to extend into a patient's glenoid, in which the glenoid attachment member of one of the plurality of bases differs from the glenoid attachment member of at least one other of the plurality of bases, and in which each of the plurality of bases includes a locking mechanism sized and shaped to lock each of the plurality of bases to the articulating member, characterised in that the opposing second side of the articulating member includes a recess defined by first, second and third sidewalls with a lip at the top of each of the said sidewalls, the second sidewall being located opposite to the third sidewall and an opening being located opposite to the first sidewall which allows a selected base to be slid between the second and third sidewalls into the recess, the locking mechanism on the articulating member comprising a locking recess in each of the second and third sidewalls and the locking mechanism on the base comprising a pair of locking protrusions which are positioned so as to be received in the locking recesses in the side walls when the base is slid fully into the recess in the articulating member.