Immobilization for acromial and scapular spine stress AU4fractures (AF/SSF) after reverse total shoulder arthroplasty (RSA) is associated with patient dissatisfaction. Our study reports the effects and safety of intranasal calcitonin alongside sling immobilization on pain and function in the treatment of AF/SSF after RSA. The treatment was regimented calcitonin (salmon) 200 unit/actuation nasal spray (1 spray/day) for 6 weeks with sling immobilization for 4 weeks. Each patient was monitored through blood work. Visual analog scale, American Shoulder and Elbow Surgeons score, and active range of motion were collected preoperatively, postoperatively, at presentation of AF/SSF, and after completion of calcitonin treatment. Two hundred eighty-two RSAs were performed by two board-certified orthopaedic surgeons, of which 18 patients sustained AF/SSF (6.4%). Ten patients met inclusion criteria (nine AFs and one SSF). After calcitonin treatment, patients demonstrated an average improvement of visual analog scale of 5.8 points, active range of motion of 46_, and American Shoulder and Elbow Surgeons score of 43.6 points at average 7.53 months after RSA. No medical complications were reported at 6-month follow-up after calcitonin treatment. The use of intranasal calcitonin was not associated withadverse events including no aberrations/signs of cancer at 6-month follow-up after administration. Calcitonin with sling immobilization markedly improved clinical and functional outcomes of patients with nondisplaced AF/SSF and may be considered by orthopaedic surgeons for symptom management.