Abstract Purpose Massive rotator cuff tear, with or without arthritis and proximal humerus fracture non-union or malunion, lead to the loss of center of rotation of shoulder, while anatomical total shoulder arthroplasty does not provide a stable center of rotation, Therefor reversed total shoulder arthroplasty (RTSA) is the suitable method for these indications, as well as in elderly patients with primary glenohumeralosteoarthritis because anatomical total shoulder arthroplasty has the risk of failure either due to loosening of glenoid component or cuff tear. This study aimed to determine the short-term results after RTSA in patients a with massive cuff tear, acute proximal humerus fracture, proximal humerus fracture malunion or non- union, and primary glenohumeralosteoarthritis. Methods This one arm clinical trial (interventional study) conducted in Ain Shams University Hospitals included 16 patients who underwent RTSA. Short-term outcomes included constant score, American Shoulder and Elbow Surgeon (ASES) score, and range of motion (ROM). Patients with rotator cuff arthropathy, massive irreparable cuff tear with or without glenohumeralarthritis, elderly patients with acute complex proximal humerus fracture, malunited or nonunited proximal humerus fracture, and patients with glenohumeralosteoarthritis were included. Patients who were aged <50 years were excluded, as well as patients with axillary nerve injury or deltoid muscle dysfunction. Results This study included 16 patients, including 8 males and 8 females. The mean age was 64.19 years and the duration of follow up-was 1 year postoperatively. Seven Patients with massive irreparable cuff tear were included, of them, 1 had associated anterior shoulder instability and recurrent anterior dislocation, 3 had a four-part proximal humerus fracture, 2 had fracture dislocation, 2 had proximal humerus fracture non –union, 1had neglected dislocation, and 2 had glenohumeralosteoarthritis. Outcomes were followed using constant and ASES scoring systems, and ROM. The global postoperative gain was statistically significant (p < 0.001). Complication in the form of dislocation occurred in one case that had RTSA after fracture non-union. Conclusion Good clinical and functional outcomes were achieved after RTSA, not only for classic massive cuff tear indication, but for other disorders, such as acute proximal humerus fracture, fracture non-union, and primary glenohumeralosteoarthritis. However, the outcomes after irreparable cuff tear were the best among all indications, while fracture non-union had the least improvement in clinical outcomes. Improvements in prosthesis design, surgeon’s experience, and clinical results are necessary to optimize this treatment for many shoulder conditions.