In vivo hydraulic fixation including bio-rivets using biocompatible expandable fibers

Abstract

The disclosure describes implantable medical products, that include dry or partially hydrated biocompatible constructs comprising collagen fibers configured to expand in situ after implantation to frictionally engage a bone tunnel wall to thereby affix the construct in the bone tunnel.

That which is claimed: 
     
         1 . An implantable medical product, comprising:
 a dry or partially hydrated biocompatible construct comprising collagen fibers configured to expand in situ after implantation to frictionally engage a bone tunnel wall to thereby affix the construct in the bone tunnel.   
     
     
         2 . A medical product according to  claim 1 , wherein the construct comprises an array of substantially parallel polymerized collagen fibers. 
     
     
         3 . A medical product according to  claim 1 , wherein the fibers are NDGA polymerized collagen fibers. 
     
     
         4 . A medical product according to  claim 1 , wherein the dry or partially hydrated construct has a cross-sectional area that is between about 70-98% that of the bone tunnel before implantation. 
     
     
         5 . A medical product according to  claim 1 , wherein, after 24 hours after implantation, the construct is configured to swell to a sufficient degree to frictionally engage the bone tunnel wall to withstand a pull out force that is at least 5 N. 
     
     
         6 . A medical product according to  claim 1 , wherein after no more than 24 hours after implantation, the construct is configured to swell to a sufficient degree to frictionally engage the bone tunnel wall to withstand a pull out force that is at least about 10 N. 
     
     
         7 . A medical product according to  claim 1 , wherein the dry or partially hydrated construct has a cross-sectional area that is between about 85% to about 95% that of the bone tunnel before implantation, and wherein after no more than 24 hours after implantation, the construct is configured to swell to a sufficient degree to frictionally engage the bone tunnel wall to withstand a pull out force that is at least about 15 N. 
     
     
         8 . A medical product according to  claim 1 , wherein the construct has at least about one hundred elongate substantially parallel fibers with a diameter, on average, of between about 0.1 mm to about 0. 5 mm and defines a bio-rivet used to reside in bone tunnels in two adjacent bone plates or bone segments to thereby hold the two bone plates or segments in alignment. 
     
     
         9 . A medical product according to  claim 1 , wherein the construct has at least about one hundred elongate substantially parallel fibers with a diameter, on average, of between about 0.1 mm to about 0.5 mm and defines a bio-rivet used to connect a first bone with a bone tunnel to an adjacent plate with an aperture to align fractured bones. 
     
     
         10 . A medical product according to  claim 1 , wherein the construct is configured to reside in a cortical bone tunnel that is at least about 5 mm long. 
     
     
         11 . A medical product according to  claim 1 , wherein the construct is configured to reside in a cancellous bone tunnel that is at least about 7 mm long. 
     
     
         12 . A medical product according to  claim 1 , wherein, in a fully hydrated unconstrained state, when measured ex vivo, the construct is configured to increase in cross-sectional area, on average, at least about 100%. 
     
     
         13 . A medical product according to  claim 1 , wherein, in a fully hydrated unconstrained state, when measured ex vivo, the construct is configured to increase in cross-sectional area, on average, at least about 100%, and wherein the construct has a substantially constant length whether in the dry or partially hydrated configuration or the fully hydrated configuration. 
     
     
         14 . A medical product according to  claim 1 , wherein, in a fully hydrated unconstrained state, when measured ex vivo, the construct is configured to increase in cross-sectional area, on average, at least about 200%. 
     
     
         15 . A medical product according to  claim 1 , wherein, in a fully hydrated unconstrained state, when measured ex vivo, the construct fibers are configured, on average to increase in cross-sectional area at least about 40%. 
     
     
         16 . A medical product according to  claim 1 , wherein the construct fibers comprise an array of between about 10-150 elongate substantially parallel fibers. 
     
     
         17 . A medical product according to  claim 1 , wherein the construct has a substantially flat configuration that is sized and configured to define a ligament bioprosthesis. 
     
     
         18 . A medical product according to  claim 17 , wherein the ligament bioprosthesis is an ACL bioprosthesis. 
     
     
         19 . A medical product according to  claim 1 , wherein the construct has a substantially circular cross-sectional configuration sized and configured to define a tendon bioprosthesis. 
     
     
         20 . A medical product according to  claim 19 , wherein the tendon bioprosthesis is a flexor tendon bioprosthesis. 
     
     
         21 . An implantable ligament or tendon bioprosthesis, comprising:
 a dry or partially hydrated flexible implantable biocompatible construct having a primary body comprising polymerized collagen fibers having opposing first and second end portions, with at least one of the end portions is configured to expand in a direction that is substantially orthogonal to an axial direction of the fibers in vivo to frictionally engage a wall of a bone tunnel while the construct retains a substantially constant unconstrained length in a dry or partially hydrated state and in a fully hydrated state.   
     
     
         22 . A medical rivet, comprising:
 an implantable partially hydrated or dry rivet comprising a plurality of elongate biologically compatible fibers configured to expand when exposed to liquid to frictionally engage target local structure.   
     
     
         23 . A medical rivet according to  claim 22 , wherein the rivet is sized and configured to be slidably inserted into two aligned adjacent bone tunnels, then expand to frictionally engage respective walls thereof whereby bones housing the respective bone tunnels are held in alignment. 
     
     
         24 . A medical rivet according to  claim 22 , wherein the biologically compatible fibers comprise polymerized collagen, and wherein the rivet has a dry or partially hydrated cross-sectional area that is between about 80%-98% that of a bone tunnel configured to hold the rivet, and wherein the rivet is configured to withstand a pull out force that is at least about 10 N after 24 hours after implantation. 
     
     
         25 . A medical rivet according to  claim 22 , wherein the rivet comprises at least 100 NDGA polymerized substantially parallel collagen fibers defining a substantially cylindrical body. 
     
     
         26 . A medical rivet according to  claim 22 , wherein the rivet is sized and configured for pediatric fracture repairs to extend through bone tunnels in bone plates. 
     
     
         27 . A medical kit, comprising:
 an implantable dry or partially hydrated construct having a hydraulic fixation portion comprising collagen fibers; and   a sterile package sealably enclosing the hydraulic fixation member therein.   
     
     
         28 . A medical kit according to  claim 27 , wherein the construct is a bioprosthesis ligament for a ligament repair, augmentation or replacement. 
     
     
         29 . A medical kit according to  claim 27 , wherein the construct has a substantially substantially circular cross-sectional configuration and is a bioprosthesis for a tendon repair, augmentation or replacement. 
     
     
         30 . A medical kit according to  claim 27 , further comprising a hemostat having an axially extending center channel configured and sized to hold a leading edge portion of the dry or partially hydrated construct for insertion into a bone tunnel. 
     
     
         31 . A method of making a medical construct, comprising:
 arranging a plurality of collagen fibers into a prosthesis;   dehydrating the collagen fibers forming the prosthesis to a desired dry or partially hydrated state; and   enclosing the dry or partially hydrated prosthesis in a sterile package.   
     
     
         32 . A method according to  claim 31 , wherein the collagen fibers are held in tension during the dehydrating step. 
     
     
         33 . A method according to  claim 31 , wherein the collagen fibers are polymerized collagen fibers. 
     
     
         34 . A method according to  claim 31 , wherein the collagen fibers comprise NDGA treated collagen fibers. 
     
     
         35 . A method of affixing a medical device in position, comprising:
 inserting a dry or partially hydrated construct having a plurality of collagen fibers into a target bone tunnel having a wall;   exposing the construct to liquid after the inserting step to expand the construct after the construct is in a desired position in vivo;   frictionally engaging the wall of the bone tunnel to withstand a pull out force that is at least 5 N after 24 hours.   
     
     
         36 . A method according to  claim 35 , further comprising forming a bone tunnel having a width such that the dry or partially hydrated construct fills the bone tunnel by at least about 85% during the inserting step. 
     
     
         37 . A method according to  claim 35 , wherein, in a fully hydrated unconstrained state, when measured ex vivo, the construct is configured to increase in cross-sectional area, on average, at least about 200%.