Posterior humeral subluxation (PHS) in B2 and B3 glenoid is a cause of asymmetric long-term stress on the glenoid and the potential reason for glenoid loosening in anatomic total shoulder arthroplasty and painful glenoid erosion in hemiarthroplasty with metallic heads. We hypothesized that corrective and concentric (C2) reaming of the glenoid associated with pyrocarbon hemiarthroplasty (HA-PYC) could improve the centering of the humeral head and decrease the risk of persistent painful glenoid erosion in young and active patients with B2 and B3 glenoid.