System and Method for Joint Resurface Repair

Abstract

An implant for installation into a portion of an articular surface includes a protrusion configured to cover an un-excised portion of articular surface proximate to the implant. Another implant may form a cavity to allow the un-excised portion of articular surface to remodel over a perimeter edge of the implant. The implant may also include indentations such as grooves to promote articular cartilage remodeling over a portion of the load bearing surface of the implant. An elongated or non-round implant is also provided having two opposing concentric arcuate shaped sides, as well as a method to seat such an implant in an articular surface. A method for seating an implant without cutting articular cartilage is also provided.

1 . An implant comprising:
 a bone-facing distal surface; and   a proximal surface;   wherein said bone-facing distal surface and said proximal surface define an outer perimeter comprising at least two arcuate sections each having a concentric arcuate shape with a common center and a first and a second generally opposing side section extending generally along a length of said implant between said at least two arcuate shaped sections, wherein said outer perimeter has a truncated circular shape.   
     
     
         2 . The implant of  claim 1 , wherein said truncated circular shape comprises a circular shape truncated on two opposed sides. 
     
     
         3 . The implant of  claim 1 , further comprising a protrusion extending around at least a portion of said implant, said protrusion configured to cover an un-excised portion of an articular surface proximate said implant. 
     
     
         4 . The implant of  claim 1 , wherein said implant further comprises:
 a width extending between said two opposing side sections and through said common center; and   a length extending between said two arcuate sections and through said common center;   wherein said width is less than said length.   
     
     
         5 . The implant of  claim 4 , wherein said width extends along a medial-lateral (ML) curvature of said implant and said length extends along an anterior-posterior (AP) curvature of said implant. 
     
     
         6 . A system comprising:
 a reamer configured to remove a portion of a patient's articular surface in an area proximate to a defect site to form an excision site, said reamer comprising a blade portion configured to create a circular cutting projection when rotated about a longitudinal axis of said reamer, said circular cutting projection having a diameter greater than a width of said patient's articular surface in said portion to be removed; and   an implant comprising:
 a bone-facing distal surface; and 
 a proximal surface; 
 wherein said bone-facing distal surface and said proximal surface define an outer perimeter comprising at least two arcuate sections each having a concentric arcuate shape with a common center and a first and a second generally opposing side section extending generally along a length of said implant between said at least two arcuate shaped sections, wherein said outer perimeter has a truncated circular shape. 
   
     
     
         7 . The system of  claim 6 , wherein said bone-facing distal surface is configured to match with said excision site. 
     
     
         8 . The system of  claim 7 , wherein said outer perimeter of said implant corresponds to a perimeter of said excision site. 
     
     
         9 . The system of  claim 6 , further comprising a guide pin having a length configured to extend generally perpendicular to said articular surface proximate said defect site, said guide pin defining a working axis along said length of said guide pin. 
     
     
         10 . The system of  claim 9 , wherein said reamer is configured to translate along working axis of said guide pin. 
     
     
         11 . The system of  claim 6 , wherein said implant further comprises a screw configured to engage bone beneath said removed articular surface along said working axis. 
     
     
         12 . The system of  claim 6 , wherein said reamer comprises a generally circular blade portion. 
     
     
         13 . The system of  claim 12 , wherein said reamer comprises a shaft extending along said longitudinal axis of said reamer, wherein said generally circular blade portion extends generally radially outwardly from said shaft. 
     
     
         14 . The system of  claim 12 , wherein said generally circular blade portion is rotated about said shaft. 
     
     
         15 . The system of  claim 6 , wherein said reamer comprises:
 a shaft extending along said longitudinal axis of said reamer; and   a cutting blade extending generally radially outwardly from said shaft arm.   
     
     
         16 . The system of  claim 15 , wherein said cutting blade comprises an offset 
     
     
         17 . The system of  claim 16 , wherein said bone-facing distal surface of said implant includes a non-planar contour and wherein said offset arm of said cutting blade comprises a non-planar cutting surface configured to create said excision site including a base portion having a non-planar contour generally matching said non-planar contour of bone-facing distal surface of said implant. 
     
     
         18 . An implant for installation into an excision site formed within a patient's articular surface, said implant comprising:
 a bone-facing distal surface having a non-planar contour configured to match with a non-planar base portion of said excision site;   a screw extending generally outwardly from bone-facing distal surface, said screw configured to secure said implant within said excision site;   a proximal surface having a contour based on an original surface contour of said excised portion of said articular surface; and   an outer perimeter comprising at least two arcuate sections each having a concentric arcuate shape with a common center and a first and a second generally opposing side section extending generally along a length of said implant between said at least two arcuate shaped sections, wherein said outer perimeter has a truncated circular shape.   
     
     
         19 . The implant of  claim 18 , wherein said truncated circular shape comprises a circular shape truncated on two opposed sides. 
     
     
         20 . The implant of  claim 18 , wherein said implant further comprises:
 a width extending between said two opposing side sections and through said common center, said width extending along a medial-lateral (ML) curvature of said implant; and   a length extending between said two arcuate sections and through said common center, said length extending along a anterior-posterior (AP) curvature of said implant;   wherein said width is less than said length.