Parsons M, Greene A, Polakovic S, et al. - The inter- and intrasurgeon variability in preoperative planning a series of reverse total shoulder arthroplasty (RTSA) cases were evaluated to distinguish variations in how surgeons consider optimal implant placement. Researchers panned a total of 49 computed tomography scans from actual RTSA cases for RTSA by 9 fellowship-trained shoulder surgeons using the same platform (Exactech GPS, Exactech Inc., Gainesville, FL, USA). Each case was planned a second time 6-12 weeks later.  This research indicates substantial variability both between surgeons and between rounds for individual surgeons when planning RTSA. There were large differences in specific cases implying little consensus on optimal planning parameters and opportunities to establish guidelines based on glenoid pathoanatomy, although average differences between plans were relatively small. The association of preoperative planning with clinical outcomes will guide to develop such guidelines.