System and method for retrograde procedure
A system and method may be used for accessing an articular surface and for preparing an implant site on the articular surface. The method may include locating a portion of the articular. An access passage may be drilled towards the articular surface though bone behind the articular surface. An implant site may be excised in the articular surface relative to an axis defined by the access passage.
1. A method of replacing a portion of an articular surface comprising:
locating a portion of said articular surface;
creating an access tunnel through bone behind said articular surface, said tunnel extending toward said articular surface;
securing at least a part of a guide sheath to, and at least partially within, said access tunnel and below said articular surface; and
excising at least a portion of said articular surface, said excising comprising inserting an excision tool at least partially through said secured guide sheath.
2. A method according to claim 1 , wherein locating a portion of said articular surface comprises providing a reference axis extending through said articular surface relative to said portion of said articular surface.
3. A method according to claim 2 , wherein providing said reference axis comprises providing a drill guide having a cannulated shaft comprising a lumen defining an axis extending through said articular surface relative to said portion of said articular surface.
4. A method according to claim 3 , wherein providing said reference axis further comprises inserting a guide pin through said cannulated shaft and into said bone behind said articular surface.
5. A method according to claim 4 , wherein creating said access tunnel comprises drilling a passage over said guide pin.
6. A method according to claim 1 , wherein securing said guide sheath comprises threadably engaging said guide sheath in said access tunnel.
7. A method according to claim 1 , wherein excising at least a portion of said articular surface comprises inserting an excision tool at least partially through said guide sheath and deploying a cutting blade.
8. A method according to claim 7 , further comprising rotating said excision tool and translating said excision tool relative to said articular surface to create an excision site.
9. A method according to claim 1 , wherein excising at least a portion of said articular surface comprises translating said excision tool relative to said articular surface to create an excision site.
10. A method according to claim 9 , wherein said excision site has a cross-section that is larger than a cross-section of said access tunnel.
11. A method according to claim 9 , wherein translating said excision tool relative to said articular surface to create said excision site comprises translating said excision tool until said excision tool contacts said guide sheath.
12. A method according to claim 9 , wherein securing said at least a part of said guide sheath comprises securing said guide sheath to, and at least partially within, said access tunnel a predetermined distance from said articular surface.
13. A method according to claim 12 , wherein said predetermined distance generally corresponds to a depth of said excision site.
14. A method according to claim 9 , further comprising inserting an implant at least partially within said excision site.
15. A method according to claim 9 , wherein said excision tool comprises:
a shaft configured to be received through said guide sheath and to axially rotate therein relative to said longitudinal axis of said guide sheath; and
at least one cutter coupled to said shaft to axially rotate with said shaft relative to said longitudinal axis of said guide sheath to excise said a least a portion of said articular surface in a retrograde manner as said at least one cutter is urged towards a distal end of said guide sheath.
16. A method according to claim 15 , wherein said at least one cutter includes at least a portion of a cutting surface extending radially outwardly beyond an outer diameter of said guide sheath and a shelf configured to contact against said distal end of said guide sheath to control a depth of said excision site as said excision tool is urged towards said distal end of said guide sheath in a retrograde manner.
17. A method according to claim 1 , wherein said guide sheath comprises a generally tubular body defining a passageway extending along a longitudinal axis of said guide sheath from a proximal end to a distal end of said guide sheath.
18. A method according to claim 17 , wherein at least a portion of an outer surface of said tubular body includes a threaded portion configured to engage with said access tunnel such that said guide sheath is configured to provide positive alignment with a reference axis of said access tunnel.
19. A method according to claim 1 , wherein a distal end of said guide sheath comprises a taper configured to facilitate alignment of said guide sheath with said access tunnel
20. A method of replacing a portion of an articular surface comprising:
locating a portion of said articular surface;
creating an access tunnel through bone behind said articular surface, said tunnel extending toward said articular surface;
securing at least a part of a guide sheath to, and at least partially within, said access tunnel and below said articular surface;
inserting an excision tool at least partially through said guide sheath; and
rotating said excision tool and translating said excision tool relative to said articular surface to create an excision site.