Patent ID: 7749223

Claim:
A kit of instruments determining an axis of a femur based on a femur intramedullary canal comprising: an axially extending shaft having a proximal and a distal end, the proximal end having a location element for positioning a pointer of an optical navigation system thereon; a plurality of distal sizers of different sizes for releasably engaging the distal end of said shaft the distal sizers having a central longitudinal axis co-axial with a longitudinal axis of the shaft when engaging the shaft; a plurality of proximal sizers of differing sizes each having a proximal and a distal end for releasably engaging said proximal shaft end and slidably moveable axially therealong after said releasable engagement in the proximal to distal direction, each proximal sizer having a u-shaped recess with an open side extending axially from the proximal to the distal end thereof allowing for the releasable engagement with said shaft by movement in a direction transverse to a longitudinal axis of said shaft, the proximal sizers having a central longitudinal axis co-axial with both the shaft longitudinal axis and the distal sizer longitudinal axis when engaged on the shaft the proximal sizers independent of the distal sizers; wherein the proximal sizers are wedge elements having a conical surface formed adjacent a distal end thereof and formed about the central longitudinal axis of the proximal sizer and the U-shaped recess having a bore with an open side for engagement with a shaft by movement of said wedge element in a direction transverse to a shaft longitudinal axis and slidable axially along said shaft after being mounted thereon in a direction from said proximal to said distal end, the bore in the U-shaped recess including a radially inwardly extending stop element for engaging the shaft; and an insertion sleeve engageable with the proximal shaft end for moving said proximal sizer from the proximal end towards the distal end of the shaft.