Materials and methods: A consecutive 106 total shoulder arthroplasty cases for primary glenohumeral
osteoarthritis were studied. We classified glenoids by direct visualization and noted lines of biconcavity
demarcation and erosion in B2s. We then calculated the ‘‘angle of erosion’’ as that between the back
side of the unsupported, smooth-backed glenoid sizer disk and the neoglenoid. We obtained depth
measurements throughout the reaming process and monitored subchondral bone.