Epicondylar axis referencing drill guide

Abstract

A tool and a method for laying out resection or alignment features to prepare a bone end for prosthetic joint replacement. The tool includes adjustable assemblies coupled to a main body for determining a preparatory cut to fit a prosthesis, for example by drilling positioning holes or otherwise setting one or more preparatory cuts, and further includes elements for sizing the prosthesis. The body carries a sighting, pointer or caliper assembly which aligns to or is positioned on the medial and lateral epicondyles, and aligns the body along the epicondylar axis, while one or more other assemblies determine a line, depth or other positioning component to adjust the position of the body with respect to other landmarks before anchoring the assembly and performing cuts. In prototype embodiments, the body positions a drill guide to locate positioning pin holes in the femur. Preferably, a template or one or more sets of graduations constitute a sizing jig in the tool, which may determine an offset, and the drill positioning block is coupled so that it positions drill holes on the bone end in coordination with sizing jig or other offset indicators. The device allows the surgeon to confirm or change the prosthesis size with regard to landmarks, and to visualize its fit in different translated positions. The drill holes may set a position for a standard cutting block to fit a femoral end component. Further, by manually shifting the assembly while the cortex hook contacts the anterior femoral surface, the prosthesis may be aligned with the trochlear groove of the femur to improve patellar tracking. Preferably, the tool places drill holes in position for a standard set of cutting blocks to fit a femoral end component of a prosthetic knee.