Cancellous constructs, cartilage particles and combinations of cancellous constructs and cartilage particles

Abstract

Constructs that are at least partially constructed of allograft cancellous bone are disclosed, along with cartilage particles that may be used with the constructs for repairing articular cartilage defects. A multi-piece construct includes a base member, a cap member and at least one pin that secures the cap member to the base member. The base member may be constructed of mineralized cancellous bone, and is used to replace the subchondral bone removed when a surgeon cuts a bore in the area of an adjacent cartilage defect. The base member includes a blind bore and first and second through-going transverse bores in opposite sides of a wall of the base member. The cap member includes an upper section that has a thickness that is similar to that of a patient's surrounding articular cartilage layer and a stem depending from the upper section that is dimensioned to be received in and by the blind bore of the base member. The stem includes a transverse through-going bore, which may be aligned with the transverse through-going bores of the base member to receive the pin therein when the construct has been assembled. The cap member is at least partially formed of demineralized allograft cancellous bone, into which a mixture containing lyophilized, freeze-milled allograft cartilage particles may be infused for the repair of articular cartilage defects. The cartilage particles have a size within a range of from about 10 microns to about 210 microns.

1 . A construct for repairing an articular cartilage defect, comprising:
 a cap member at least partially derived from demineralized cancellous bone, said cap member including a plurality of freeze-milled cartilage particles, at least a majority of which have a dimension, when dry, that does not exceed 210 microns.   
   
   
       2 . The construct of  claim 1 , further comprising a base member having first and second ends, said base member including a first bore extending into said base member from said first end in a generally axial direction, and a second bore extending generally transversely from an exterior wall of said base member to said first bore,
 wherein said cap member includes an upper section and a stem depending from said upper section, said stem being dimensioned to insertably engage said first bore such that said upper section is adjacent said first end of said base member, and said stem including a third bore extending generally transversely into said stem from an exterior surface thereof, said third bore being alignable with said second bore when said stem is in engagement with said first bore; and   at least one pin which is dimensioned to engage said second bore and said third bore when said second bore and said third bore are aligned, thereby securing said cap member to said base member.   
   
   
       3 . The construct of  claim 1 , further comprising a base member having first and second ends, said base member including a first bore extending into said base member from said first end in a generally axial direction, a second bore extending generally transversely from an exterior wall of said base member to said first bore, and a third bore extending generally transversely from said exterior wall of said base member to said first bore, said third bore being formed opposite said second bore and alignable with said second bore, said base member including an upper annular edge adjacent said first end and said first bore, and an island formed in said bore so as to be substantially concentrically positioned with respect to said upper annular edge and to form an annular recess between said island and an interior wall of said base member adjacent said upper annular edge;
 wherein said cap member includes an upper section and a stem depending from said upper section, said stem being dimensioned to insertably engage said first bore, such that said upper section is adjacent said first end of said base member, wherein said stem is hollow and includes a cavity formed therein, said cavity being dimensioned to receive said island therein, said annular recess of said base member being dimensioned to receive said stem therein, said stem including a fourth bore extending generally transversely into said stem from an exterior surface thereof, said fourth bore being alignable with said second bore and said third bore when said stem is in engagement with said first bore, said stem including a fifth bore extending generally transversely into said stem from said exterior wall thereof, said fifth bore being formed opposite said fourth bore and alignable with said second bore and said third bore when said stem is in engagement with said first bore;   wherein said island includes a sixth bore which extends generally transversely between opposed exterior surfaces of said island, said sixth bore being alignable with said second bore, said third bore, said fourth bore and said fifth bore when said stem is in engagement with said first bore; and   at least two pins which are dimensioned to engage said second bore, said third bore, said fourth bore, said fifth bore and said sixth bore when said second bore, said third bore, said fourth bore, said fifth bore and said sixth bore are aligned, thereby securing said cap member to said base member.   
   
   
       4 . The construct of  claim 1 , further comprising a base member having first and second ends, said base member including a bore extending into said base member from said first end in a generally axial direction, said bore including a proximal portion and an adjoining distal portion, wherein a dimension of said distal bore portion is greater than a corresponding dimension of said proximal bore portion; and
 wherein said cap member includes an upper section and a stem depending from said upper section, said stem including a proximal portion and an adjoining distal portion, wherein said distal stem portion is dimensioned so as to closely fit within said distal bore portion and said proximal stem portion is dimensioned so as to closely fit within said proximal bore portion, wherein said distal stem portion is deformable from an uncompressed state to a compressed state in which a dimension of said distal stem portion is smaller than a dimension of said proximal bore portion and said distal stem portion is insertable through said proximal bore portion and into said distal bore portion, wherein said distal stem portion expands from said compressed state to said uncompressed state, so that said dimension of said distal stem portion is greater than said dimension of said proximal bore portion, whereby said cap member is secured to said base member.   
   
   
       5 . The construct of  claim 1 , further comprising a base member having first and second ends, said base member including a bore extending into said base member from said first end in a generally axial direction;
 a sleeve member derived from cortical bone, said sleeve member being dimensioned to receive said base member therein,   wherein said cap member includes an upper section and a stem depending from said upper section, said stem being dimensioned to insertably engage said bore; and   means for securing said cap member to said base member.   
   
   
       6 . The construct of  claim 1 , wherein said cap member is disc-shaped and has a height that is similar to the thickness of an articular cartilage layer in a mammalian joint. 
   
   
       7 . The construct of  claim 1 , further comprising a base member that is integrally connected to said cap member. 
   
   
       8 . A construct for repairing an articular cartilage defect, comprising:
 a base member having first and second ends, said base member including a first bore extending into said base member from said first end in a generally axial direction, and a second bore extending generally transversely from an exterior wall of said base member to said first bore;   a cap member at least partially derived from demineralized cancellous bone and including an upper section and a stem depending from said upper section, said stem being dimensioned to insertably engage said first bore, such that said upper section is adjacent said first end of said base, and said stem including a third bore extending generally transversely into said stem from an exterior surface thereof, said third bore being alignable with said second bore when said stem is in engagement with said first bore; and   at least one pin which is dimensioned to engage said second bore and said third bore when said second bore and said third bore are aligned, thereby securing said cap member to said base member.   
   
   
       9 . The construct of  claim 8 , wherein said base member includes a fourth bore extending generally transversely from said exterior wall of said base member to said first bore, said fourth bore being formed opposite said second bore and alignable with said second bore and said third bore when said stem is in engagement with said first bore, wherein said at least one pin is dimensioned to engage said second bore, said third bore and said fourth bore when said second bore, said third bore and said fourth bore are aligned, thereby securing said cap member to said base member. 
   
   
       10 . The construct of  claim 9 , wherein said cap member is loaded with a plurality of freeze-milled cartilage particles having a size within a range from about 10 microns to about 210 microns. 
   
   
       11 . The construct of  claim 8 , wherein said base member includes an upper annular edge adjacent said first end and said first bore, and an island formed in said first bore so as to be substantially concentrically positioned with respect to said upper annular edge and to form an annular recess between said island and an interior wall of said base member adjacent said upper annular edge,
 wherein said base member includes a fourth bore extending generally transversely from said exterior wall of said base member to said first bore, said fourth bore being formed opposite said second bore and alignable with said second bore and said third bore when said stem is in engagement with said first bore,   wherein said stem is hollow and includes a cavity formed therein, said cavity being dimensioned to receive said island therein, said annular recess of said base member being dimensioned to receive said stem therein, said stem including a fifth bore extending generally transversely into said stem from said exterior surface thereof, said fifth bore being formed opposite said third bore and alignable with said second bore and said fourth bore when said stem is in engagement with said first bore,   wherein said island includes a sixth bore which extends generally transversely between opposed exterior surfaces of said island, said sixth bore being alignable with said second bore, said third bore, said fourth bore and said fifth bore when said stem is in engagement with said first bore; and   wherein said at least one pin includes first and second pins which are dimensioned to engage said second bore, said third bore, said fourth bore, said fifth bore and said sixth bore when said second bore, said third bore, said fourth bore, said fifth bore and said sixth bore are aligned, thereby securing said cap member to said base member.   
   
   
       12 . The construct of  claim 11 , wherein said cap member is loaded with a plurality of freeze-milled cartilage particles having a size within a range from about 10 microns to about 210 microns. 
   
   
       13 . A cartilage defect repair material,
 comprising freeze-milled allograft cartilage particles having a size within a range of from about 10 microns to about 210 microns.   
   
   
       14 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage particles are mixed with a biocompatible carrier, so as to form a mixture. 
   
   
       15 . The cartilage defect repair material as claimed in  claim 14 , wherein said biocompatible carrier is a bioabsorbable carrier. 
   
   
       16 . The cartilage defect repair material as claimed in  claim 14 , wherein said mixture includes an additive selected from the group consisting of a growth factor, human demineralized bone matrix, insulin, insulin-like growth factor-1, interleukin-1 receptor agonist, hepatocyte growth factor, platelet-derived growth factor, Indian hedgehog, transformative growth factor and parathyroid hormone-related peptide. 
   
   
       17 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage particles have a mean equivalent spherical diameter of about 26 microns. 
   
   
       18 . The cartilage defect repair material as claimed in  claim 30 , wherein said cartilage particles are formed by freeze-milling allograft cartilage subsequent to lyophilization. 
   
   
       19 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage particles have an aspect ration of about 1.57. 
   
   
       20 . The cartilage defect repair material as claimed in  claim 30  wherein said cartilage particles are formed from allograft cartilage that has been lyophilized so as to reduce its water content to an amount within the range of from about 0.1% to about 8.0% by weight. 
   
   
       21 . A method of placing the cartilage defect repair material of  claim 13  in a cartilage defect site, said method comprising the steps of:
 (a) cutting a patient's tissue to remove diseased cartilage from the cartilage defect site;   (b) placing said cartilage defect repair material into the cartilage defect site; and   (c) placing a cover over the placed cartilage defect repair material.   
   
   
       22 . A method for making the cartilage defect repair material of  claim 30 , said method comprising the steps of:
 lyophilizing allograft cartilage; and   freeze-milling said allograft cartilage so as to form said cartilage particles.   
   
   
       23 . A method of repairing articular cartilage, comprising the step of:
 placing a therapeutically effective amount of the cartilage defect repair material of  claim 13  into a cartilage defect site, wherein, subsequent to placement of the therapeutically effective amount of the cartilage defect repair material into the cartilage defect site, a greater percentage of repair tissue generated in the cartilage defect site is articular cartilage as compared to equivalent cartilage defect sites left untreated or treated with microfracture.   
   
   
       24 . The method of  claim 23 , wherein the percentage of repair tissue generated is subsequently assessed by relative uptake of Safranin-o and/or anti-collagen  11  staining materials by the repair tissue. 
   
   
       25 . The construct of  claim 1 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       26 . The construct of  claim 1 , wherein said cap member includes demineralized bone matrix. 
   
   
       27 . The construct of  claim 8 , wherein said cap member includes demineralized bone matrix. 
   
   
       28 . The construct of  claim 10 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       29 . The construct of  claim 12 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       30 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       31 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage defect repair material is sterile. 
   
   
       32 . The cartilage defect repair material as claimed in  claim 13 , wherein said cartilage particles are devitalized. 
   
   
       33 . The method as claimed in  claim 22 , further comprising the step of lyophilizing said cartilage particles. 
   
   
       34 . The method as claimed in  claim 33 , further comprising the step of hydrating said cartilage particles before the performance of said lyophilizing step. 
   
   
       35 . A construct for repairing an articular cartilage defect comprising:
 a disc derived from demineralized cancellous bone, said disc including a plurality of freeze-milled cartilage particles, at least a majority of which have a dimension, when dry, that does not exceed 210 microns.   
   
   
       36 . The construct of  claim 35 , wherein said disc includes demineralized bone matrix. 
   
   
       37 . The construct of  claim 35 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       38 . A construct for repairing an articular cartilage defect comprising:
 an integral one-piece, two phase construct including a demineralized cancellous bone cap and a mineralized cancellous bone base attached thereto.   
   
   
       39 . The construct of  claim 38 , wherein said demineralized cancellous bone cap includes demineralized bone matrix. 
   
   
       40 . The construct of  claim 38 , said demineralized cancellous bone cap including a plurality of freeze-milled cartilage particles, at least a majority of which have a dimension, when dry, that does not exceed 210 microns. 
   
   
       41 . The construct of  claim 40 , wherein said cartilage particles are formed from allograft cartilage that has been lyophilized. 
   
   
       42 . A cartilage defect repair material, comprising allograft cartilage particles having a size ranging from 0.01 mm to 0.21 mm.