A system for forming keel openings in tibial bone includes a plurality of templates having different sizes, each template having a top surface, a bottom surface and a central opening extending between the top and bottom surfaces. The system includes a bone cutting instrument for forming the keel openings and a guide having a leading end that is adapted to be coupled with the templates so that the leading end of the guide is aligned with the central openings in the templates. The guide includes a plurality of slots extending toward the leading end thereof for guiding advancement of the bone cutting instrument through the central openings in the templates. Each slot is associated for use with one of the differently sized templates.