This monocentric observational cohort study compares conventional instrumentation, patient-specific instrumentation, and augmented reality navigation in reverse total shoulder arthroplasty. The primary objective is to assess the accuracy of glenoid component positioning based on postoperative CT data. Secondary objectives include evaluation of functional outcomes and clinical performance at mid-term follow-up. Patients who underwent surgery between 2021 and 2024 are followed up clinically at 2 years postoperatively.