The indications for surgical intervention in complex fractures of the proximal humerus are disputed. In elderly patients with poor bone stock it may be impossible to obtain satisfactory fixation of the tuberosities to a hemiarthroplasty (HA). In such cases primary insertion of a reverse shoulder arthroplasty (RSA) has been suggested. We aimed to review clinical studies reporting benefits and harms of RSA in acute fractures. A systematic review. We included 18 studies containing 430 RSA in acute fractures. We found no randomized clinical trials. Four studies compared outcome after RSA with a historical control group of HA. The median constant score was 58 (range 44-68) which is comparable to previous reviews of HA in 4-part fractures. Complications included dislocation, infection, hematoma, instability, neurological injury, reflex sympathetic dystrophy, intraoperative fractures, periprosthetic fractures, and baseplate failure. Scapular notching was reported in 11 studies with a median value of 25% (range 0-94). Heterogeneity of study designs and lack of primary data precluded statistical pooling of data. No high quality evidence was identified. Based on the available evidence the use of RSA in acute fractures is questionable. The complication rate was high and the clinical implications of long term scapular notching are worrying. Randomized studies with long term follow up using the latest techniques of tubercular reinsertion in RSA toward HA should be encouraged.