A 62-year-old male with obstetric brachial plexus injury (OBPI) from Erb’s palsy sought surgical treatment after nonoperative approaches failed. The primary goal was pain reduction, with shoulder function improvement as a secondary goal. Preoperative imaging showed humeral head impaction, severe post-traumatic glenohumeral osteoarthritis, and severe glenoid dysplasia. Reverse total shoulder arthroplasty (RTSA) with glenoid bone graft/augment was chosen for treatment.