Cartilage resurfacing implant

Abstract

A cartilage resurfacing implant is provided for replacing cartilage of an articulating portion of a bone at a skeletal joint having opposed joint surfaces. The cartilage resurfacing implant includes a body having a bearing surface and a bone interface. The bearing surface is able to support articulation with an opposing joint surface.

1 . A cartilage resurfacing implant for replacing articular cartilage of an articulating portion of a bone at a skeletal joint having articulating opposed joint surfaces, the cartilage resurfacing implant comprising: 
 a flexible body having a bearing surface and a bone interface, the bearing surface being able to support articulation with an opposing joint surface, the body being sufficiently flexible to conform to the shape of the bone in vivo.    
   
   
       2 . The cartilage resurfacing implant of  claim 1  wherein the body is flexibly deformable in response to normal joint articulation to conform to the opposed joint surfaces.  
   
   
       3 . The cartilage resurfacing implant of  claim 1  further comprising a plurality of reinforcing fibers embedded in the body, the reinforcing fibers extending from the bone interface to define a bone attachment.  
   
   
       4 . The cartilage resurfacing implant of  claim 3  wherein the body has a relatively higher stiffness near the bone interface and a relatively lower stiffness near the bearing surface.  
   
   
       5 . The cartilage resurfacing implant of  claim 4  wherein the body defines a stiffness gradient varying from relatively high near the bone interface to relatively low near the bearing surface.  
   
   
       6 . The cartilage resurfacing implant of  claim 5  wherein the body comprises a porous substrate defining a pore gradient varying from relatively small pores near the bone interface to relatively large pores near the bearing surface.  
   
   
       7 . The cartilage resurfacing implant of  claim 5  wherein the body comprises a porous substrate that varies from a relatively low pore density near the bone interface to a relatively high pore density near the bearing surface.  
   
   
       8 . The cartilage resurfacing implant of  claim 5  wherein the body comprises a crosslinked polymer structure that varies from more highly crosslinked near the bone interface to less highly crosslinked near the articular surface.  
   
   
       9 . The cartilage resurfacing implant of  claim 8  wherein the body comprises a crosslinked hydrogel.  
   
   
       10 . The cartilage resurfacing implant of  claim 3  wherein the body comprises a hydrogel.  
   
   
       11 . The cartilage resurfacing implant of  claim 5  wherein the reinforcing fibers comprise a percentage of the body composition that varies from a relatively high percentage of fiber reinforcement near the bone interface to a relatively low percentage of fiber reinforcement near the bearing surface.  
   
   
       12 . The cartilage resurfacing implant of  claim 5  wherein the reinforcing fibers comprise differing strengths of fibers that vary from relatively strong fibers near the bone interface to relatively less strong fibers near the articular surface.  
   
   
       13 . The cartilage resurfacing implant of  claim 12  wherein the body comprises metal fibers near the bone interface, high strength polymer fibers between the bone interface and bearing surface, and hydrogel fibers near the bearing surface.  
   
   
       14 . The cartilage resurfacing implant of  claim 3  wherein fibers extend from the bone interface to define flexible cables securable to the bone.  
   
   
       15 . The cartilage resurfacing implant of  claim 3  wherein fibers extend from the bone interface to define slender bristles distributed across the bone interface able to spread the fixation load evenly over the bone interface.  
   
   
       16 . The cartilage resurfacing implant of  claim 15  wherein the bristles comprise a main shaft and barbs extending outwardly from the main shaft to engage the bone.  
   
   
       17 . The cartilage resurfacing implant of  claim 3  wherein fibers extend from the bone interface to define one component of a hook-and-loop fastener arrangement.  
   
   
       18 . The cartilage resurfacing implant of  claim 17  wherein the fibers define hooks, the cartilage resurfacing implant further comprising a separate loop component able to be pre-installed on the bone and defining loops engageable with the hooks.  
   
   
       19 . The cartilage resurfacing implant of  claim 3  wherein the bone attachment comprises expandable pegs projecting from the bone interface.  
   
   
       20 . The cartilage resurfacing implant of  claim 19  wherein the pegs comprise an at least partially dehydrated hydrogel expandable by contact with body fluids.  
   
   
       21 . The cartilage resurfacing implant of  claim 19  wherein the pegs comprise heat expandable pegs.  
   
   
       22 . The cartilage resurfacing implant of  claim 3  further comprising an adhesive selected from the group consisting of fibrin glue, cyanoacrylate, epoxy, and bone cement.  
   
   
       23 . The cartilage resurfacing implant of  claim 3  further comprising a bone growth substance selected from the group consisting of bone paste, bone chips, bone growth proteins, bone growth peptides, bone marrow aspirate, stem cells, bone attachment proteins, and bone attachment peptides.  
   
   
       24 . The cartilage resurfacing implant of  claim 1  further comprising a set of similarly constructed bodies varying in size and shape selectable to repair differently sized and shaped cartilage defects.  
   
   
       25 . The cartilage resurfacing implant of  claim 1  wherein the body is intraoperatively shapable to a desired shape and size.  
   
   
       26 . A cartilage resurfacing implant for replacing articular cartilage of an articulating portion of a bone at a skeletal joint having articulating opposed joint surfaces, the cartilage resurfacing implant comprising: 
 a body having a bearing surface and a bone interface, the bearing surface being able to support articulation with an opposing joint surface; and    a plurality of reinforcing fibers embedded in the body, the reinforcing fibers extending from the bone interface to define flexible cables securable to the bone.    
   
   
       27 . A cartilage resurfacing implant for replacing articular cartilage of an articulating portion of a bone at a skeletal joint having articulating opposed joint surfaces, the cartilage resurfacing implant comprising: 
 a body having a bearing surface and a bone interface, the bearing surface being able to support articulation with an opposing joint surface; and    a plurality of reinforcing fibers embedded in the body, the reinforcing fibers extending from the bone interface to define slender bristles distributed across the bone interface able to spread the fixation load evenly over the bone interface.    
   
   
       28 . The cartilage resurfacing implant of  claim 27  wherein the bristles comprise a main shaft and barbs extending outwardly from the main shaft to engage the bone.  
   
   
       29 . A cartilage resurfacing implant for replacing articular cartilage of an articulating portion of a bone at a skeletal joint having articulating opposed joint surfaces, the cartilage resurfacing implant comprising: 
 a body having a bearing surface and a bone interface, the bearing surface being able to support articulation with an opposing joint surface; and    a plurality of reinforcing fibers embedded in the body, the reinforcing fibers extending from the bone interface to define one component of a hook-and-loop fastener arrangement.    
   
   
       30 . The cartilage resurfacing implant of  claim 29  wherein the fibers define hooks, the cartilage resurfacing implant further defining a separate loop component able to be pre-installed on the bone and defining loops engageable with the hooks.  
   
   
       31 . A cartilage resurfacing implant for replacing articular cartilage of an articulating portion of a bone at a skeletal joint having articulating opposed joint surfaces, the cartilage resurfacing implant comprising: 
 a body having a bearing surface and a bone interface, the bearing surface being able to support articulation with an opposing joint surface; and    a plurality of expandable pegs projecting from the bone interface, the pegs expandable in response to implantation adjacent to the bone.    
   
   
       32 . The cartilage resurfacing implant of  claim 31  wherein the pegs comprise fluid expandable pegs.  
   
   
       33 . The cartilage resurfacing implant of  claim 32  wherein the pegs comprise an at least partially dehydrated hydrogel expandable by contact with body fluids.  
   
   
       34 . The cartilage resurfacing implant of  claim 33  wherein reinforcing fibers from the body extend into the pegs.  
   
   
       35 . The cartilage resurfacing implant of  claim 31  wherein the pegs comprise expanding barbs.  
   
   
       36 . The cartilage resurfacing implant of  claim 31  wherein the pegs comprise heat expandable pegs.  
   
   
       37 . The cartilage resurfacing implant of  claim 31  wherein the pegs comprise a shape memory alloy.