Assembled Cartilage Repair Graft

Abstract

Bifunctional and assembled implants are provided for osteochondral implantation.

1 . A bifunctional assembled implant adapted for implantation at a site of a bone cartilage junction, comprising:
 an osteoconductive portion adapted to fill a defect in a subchondral bone layer; and   a chondroinductive portion adapted to fill a cartilage layer adjacent to the subchondral bone layer;   wherein said osteoconductive portion and said chondroinductive portion are derived from different source materials and are assembled in a stacked relationship.   
   
   
       2 . The implant of  claim 1 , wherein said osteoconductive portion and said chondroinductive portion each defines a characteristic depth and a characteristic width; and
 wherein said characteristic depth of said osteoconductive portion is substantially equivalent to or greater than said characteristic depth of said chondroinductive portion.   
   
   
       3 . The implant of  claim 2 , wherein said characteristic depth of said osteoconductive portion is at least about one and one half times greater than said characteristic depth of said chondroinductive portion; and wherein said characteristic width of said osteoconductive portion is substantially the same as said characteristic width of said chondroinductive portion. 
   
   
       4 . The implant of  claim 2 , wherein said osteoconductive portion and said chondroinductive portion are assembled to have an interference fit. 
   
   
       5 . The implant of  claim 4 , wherein said interference fit is a hydration controlled shrink fit. 
   
   
       6 . The implant of  claim 6 , wherein said interference fit further comprises a shaft and bore fit between said osteoconductive portion and said chondroinductive portion, and the shaft is straight or tapered. 
   
   
       7 . The implant of  claim 1 , wherein said chondroinductive portion comprises a demineralized cortical bone portion. 
   
   
       8 . The implant of  claim 7 , wherein said demineralized cortical bone portion includes one or more canals, said canals being oriented in a direction communicating between said osteoconductive portion and at least one surface of said demineralized cortical bone portion. 
   
   
       9 . The implant of  claim 8 , wherein said demineralized cortical bone portion comprises from two to eight pieces of cortical bone 
   
   
       10 . The implant of  claim 8 , wherein said osteoconductive portion substantially surrounds at least one part of said chondroinductive portion. 
   
   
       11 . The implant of  claim 8 , wherein said demineralized cortical bone portion consists essentially of a single piece of substantially demineralized cortical bone. 
   
   
       12 . The implant of  claim 1 , wherein:
 said osteoconductive portion consists essentially of cancellous bone, and said chondroinductive portion consists essentially of cortical bone.   
   
   
       13 . The implant of  claim 13 , wherein said chondroinductive portion comprises allograft bone, xenograft bone, or a combination thereof. 
   
   
       14 . (canceled) 
   
   
       15 . The implant of  claim 12 , wherein said bifunctional assembled implant does not comprise separate fasteners for holding together said osteoconductive portion and said chondroinductive portion. 
   
   
       16 . The implant of  claim 12 , wherein said bifunctional assembled implant does not comprise an adhesive for holding together said osteoconductive portion and said chondroinductive portion. 
   
   
       17 . The implant of  claim 1 , wherein said osteoconductive portion comprises cancellous bone material and said chondroinductive portion comprises cortical bone material; and wherein said osteoconductive portion and said chondroinductive portion are joined by a hydration controlled shrink fit, and wherein a part of said osteoconductive portion surrounds a part of said chondroinductive portion. 
   
   
       18 . The implant of  claim 17 , wherein said cortical bone material further includes one or more canals, said canals being oriented in a direction providing transport between said cancellous bone material and said cortical bone material. 
   
   
       19 . A method of using an assembled osteochondral implant, comprising filling a defect site with said bifunctional assembled implant of  claim 1 , such that a first region of said defect site is filled by osteoconductive cancellous bone material and a second region of said defect site is filled by chondroinductive cortical bone material. 
   
   
       20 . An implant adapted for implantation at an articulating cartilage site, comprising a membrane of demineralized cortical bone, wherein the membrane has a thickness, a length and a width, and wherein said thickness is less than said length and said width, and wherein the membrane includes natural Haversian canals oriented generally perpendicular to the thickness of said membrane. 
   
   
       21 - 24 . (canceled) 
   
   
       25 . A method of making a bifunctional assembled implant adapted for implantation at the site of a bone cartilage junction, comprising:
 providing an osteoconductive portion adapted to fill a defect in a subchondral bone layer; and   assembling said osteoconductive portion with a chondroinductive portion adapted to fill a corresponding cartilage layer;   wherein said osteoconductive portion and said chondroinductive portion are assembled via an interference fit.   
   
   
       26 - 32 . (canceled)