“…Joint instability, defined as the inability to maintain the humeral head centered in the glenoid fossa (Matsen and Fu, 1993), also represents a serious complication after conventional (Franta et al, 2007;Wirth and Rockwood, 1996) and reverse shoulder replacement (Sirveaux et al, 2004;Wall et al, 2007). Adequate treatments to restore joint stability in the presence of glenoid defects (Beran et al, 2010), atypical labrum anatomy (Kanatli et al, 2010) or with unconstrained prostheses (Gonzalez et al, 2011) remain limited.…”