Patent ID: 7914545

Claim:
A system for creating an implant site on an articular surface of a bone comprising: a sheath comprising a generally tubular body defining a passageway extending along a longitudinal axis of said sheath from a proximal end to a distal end of said sheath, wherein at least a portion of an outer surface of said tubular body includes a threaded portion configured to engage with a tunnel extending within said bone such that said sheath is configured to provide positive alignment with a reference axis of said tunnel extending through said articular surface; and an excision device comprising: a shaft configured to be received through said proximal end of said sheath and to axially rotate within said passageway relative to said longitudinal axis of said sheath; and at least one cutter coupled to said shaft to axially rotate with said shaft relative to said longitudinal axis of said sheath to excise a least a portion of said articular surface in a retrograde manner as said at least one cutter is urged towards said distal end of said sheath, said at least one cutter having at least a portion of a cutting surface extending radially outwardly beyond an outer diameter of said generally tubular body of said sheath and a shelf configured to contact against said distal end of said sheath to control said depth of said implant site as said excision device is urged towards said distal end of said sheath in a retrograde manner.