Antuna et al have classified glenoid bone deficiencies after glenoid component removal into central, peripheral or combined, each with mild, moderate or severe degrees of bone loss.17 The deficiencies were classified as mild if they involved less than one-third of the glenoid surface or rim; moderate if they involved between one-third and two-thirds of the surface or rim; and severe if they involved more than two-thirds (Figure 5).