Methods for shoulder prostheses

A method for converting a modular anatomic shoulder implant to a modular reverse shoulder implant, wherein the modular anatomic shoulder implant comprises a distal stem, an anatomic metaphysis, and an anatomic humeral head, and wherein the modular reverse shoulder implant comprises the distal stem, a reverse metaphysis, and a reverse insert, the method comprising:

• removing the anatomic humeral head from the anatomic metaphysis;
• separating the anatomic metaphysis from the distal stem;
• installing a reamer guide to the distal stem;
• reaming bone using the reamer guide to guide a reamer;
• attaching the reverse metaphysis to the distal stem at one of a plurality of rotational positions and setting the reverse metaphysis into the bone;
• and
• attaching the reverse insert to the reverse metaphysis in one of a fixed number of positions, the fixed number of positions corresponding with an order of rotational symmetry of a reverse insert distal end protrusion shape with respect to a reverse metaphysis proximal end opening shape.