Shoulder prosthesis positioning and tuberosity reconstruction in fractures have until now been very approximate. Because of the “eye-balling” involved in prosthesis positioning, tuberosity reconstruction was inaccurate. Not surprisingly, clinical results were poor and unpredictable, with a high rate of greater tuberosity migration. Anatomical reconstruction of the tuberosities is possible only if the prosthesis is positioned precisely for length and retroversion. The Aequalis fracture jig is a new device designed to help surgeons position the humeral implant correctly in both height and retroversion. The principle is simple: a ruler restores the length and a protractor restores the retroversion. This extramedullary guide helps to stabilize the prosthesis and minimizes the subjective assessment of the surgeon (whose experience is often limited) allowing better positioning of the prosthesis and therefore better reconstruction of the tuberosities. As no surgeon would now consider implanting a knee prosthesis without the appropriate jig, so we believe the same course should be followed when using a prosthesis for shoulder fractures.