Epicondylar axis alignment-femoral positioning drill guide

Abstract

A tool lays out resection or alignment features to prepare a bone end for prosthetic joint replacement. The tool attaches to the end of the femur, and positions an initial cut, for example a pair of aligned drill holes for the positioning pins of a prosthesis or the cutting blocks used in preparing the distal femur. The tool includes adjustable assemblies coupled to a main body for setting its position, and these are arranged with graduations for sizing the femur. The adjustable assemblies include an epicondylar engaging assembly such as a pair of clamp arms which slide in the body to align the body along the epicondylar axis. It further includes one or more other assemblies which determine a line, offset depth or other coordinate or component of orientation to set the drill guide for optimally locating the initial cut in the femur. Preferably, the other assemblies include an A/P sizing jig in the tool which determines an offset, and the drill guide is coupled so that it positions drill holes on the bone end in coordination with sizing jig. The clamp assembly may further indicate medial/lateral offset information for shifting the center to improve tracking and alignment. This allows the surgeon to confirm or adjust both the size and the position of the prosthesis with respect to several landmarks using a single tool. The drill holes may set a position for a standard cutting block to fit the femoral end component of a prosthetic knee.