Bodendorfer BM, Loughran GJ, Looney AM, et al. - This study was undertaken to investigate short-term outcomes of reverse shoulder arthroplasty using a custom baseplate for severe glenoid deficiency. Between September 2015 and November 2018, individuals who had undergone reverse shoulder arthroplasty (RSA) with vault reconstruction system (VRS) for severe glenoid deformity or bone loss by 1 of 4 board-certified, fellowship-trained shoulder and elbow surgeons at 3 academic tertiary referral centers were eligible for inclusion. Via medical record review and telephone questionnaires, patient data were obtained.  Researchers obtained the Numeric Pain Rating Scale, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons, Penn shoulder scores, and range of motion (ROM) measurements pre- and postoperatively. This analysis enrolled 12 shoulders (11 patients) with a mean age of 68 years; 7 were primary arthroplasties and 5 were revisions. This research illustrates that RSA applying a custom VRS glenoid implant is a safe and effective technique addressing complex glenoid deformity or bone loss in both primary and revision settings. All patient-reported outcomes and ROM measures improved significantly, and no complications were reported at short-term follow-up. Further study should ascertain mid- and long-term outcomes, preferably in a prospective manner with defined patient populations.