Instrument tibial trial

A set of orthopedic surgical instrument comprising: a trial (436) of tibial base adapted to be located at one end surgically proximal prepared in a tibia of a patient, an instrument (440) surgical orthopedic intramedullary coupled with a surface (446) lower assay tibial base, and a fastener (512) configured to rotate relative to the trial tibial base, including the fastener (i) a button head (514), and (ii) a shaft (516) threaded engagement with the orthopedic surgical instrument intramedullary to couple removably the orthopedic surgical instrument intramedullary the trial tibial base, wherein the assembly includes a trial (684) of the tibial bearing includes a surface (690) of articulation and a surface ( 688) lower surface opposite the joint, including the trial tibial base surface (444) upper coupled to the lower surface of the trial tibial bearing, and the button head of the fastener located in an aperture defined in being the trial tibial bearing.