Review Question - QID 217899

A 64-year-old female presents to your office with a painful right shoulder. She had a fall one year ago, sustaining a four-part proximal humerus fracture shown in Figure A. She healed well without tuberosity malunion, however, she was indicated for a reverse total shoulder arthroplasty (rTSA) for persistent pain and dysfunction. She required a revision for component loosening and your partner placed a lateralizing center of rotation prosthesis two weeks ago. She had been doing well until she felt a pop getting into her car after physical therapy this morning. Her current radiographs are shown in Figure B. CT scan shows appropriate positioning of implants. Which of the following placed her at the most significant risk for this complication?