Reverse shoulder arthroplasty has become the classical treatment for glenohumeral joint arthritis associated with rotator cuff dysfunction. The design of the prosthesis, the fixation of the implant and the surgical technique are however still to be improved. One of the remaining question is the number and positioning of the screws that stabilize the baseplate in the glenoid bone. The goal of this project is to evaluate the advantage and stability of a 3-screws baseplate, compared to a more conventional 4-screws baseplate. This project is mainly based on finite element analysis.