A method of forming a shoulder prosthesis includes resecting an end portion of a humerus to form a resected end of the humerus and a resected portion separated from the humerus, the resected portion having an outer convex surface and an inner surface. The inner surface of the resected portion is processed to include a concave articular surface. The outer convex surface of the resected portion is implanted in the resected end of the humerus. An implant having a convex articular surface is secured to a glenoid. The concave articular surface of the resected portion is articulated with the convex articular surface of the implant.