Dual function prosthetic bone implant and method for preparing the same

Abstract

The present invention discloses a prosthetic bone implant made of a hardened calcium phosphate cement having an apatitic phase as a major phase, which includes a dense cortical portion bearing the majority of load and a porous cancellous portion allowing a rapid blood/body fluid penetration and tissue ingrowth.

1 - 40 . (canceled)  
   
   
       41 . A dual function prosthetic bone implant comprising: 
 a load bearing component; and    at least one porous component coupled to the load-bearing component;    wherein the load bearing component and the porous component comprise a hardened calcium phosphate cement, wherein the prosthetic bone implant is at least partially bioresorbable over time, wherein the configuration of the porous components relative to the load-bearing component is such that, when the prosthetic bone implant is implanted into bone, at least a portion of the load-bearing component is coupled to substantially adjacent cortical bone, and at least a portion of a porous component is coupled to substantially adjacent cancellous bone.    
   
   
       42 . The prosthetic bone implant of  claim 41 , wherein the porosity of the porous component is greater than the porosity of the load bearing component.  
   
   
       43 . The prosthetic bone implant of  claim 41 , wherein the porosity of the porous component is from about 20% by volume to about 90% by volume.  
   
   
       44 . The prosthetic bone implant of  claim 41 , wherein the porosity of the load bearing component is less than about 30% by volume.  
   
   
       45 . The prosthetic bone implant of  claim 41 , wherein the load-bearing component is adapted to withstand compressive force of greater than about 35 MPa.  
   
   
       46 . The prosthetic bone implant of  claim 41 , wherein the load bearing component is adapted to withstand a compressive force of from about 35 MPa to about 250 MPa.  
   
   
       47 . The prosthetic bone implant of  claim 41 , wherein the load bearing component is adapted to withstand a compressive force of from about 110 MPa to about 170 MPa.  
   
   
       48 . The prosthetic bone implant of  claim 41 , wherein the hardened calcium phosphate cement of the load bearing component and the hardened calcium phosphate cement of the porous component is made from at least one calcium phosphate source.  
   
   
       49 . The prosthetic bone implant of  claim 48 , wherein the calcium phosphate source comprises alpha-tricalcium phosphate (α-TCP), beta-tricalcium phosphate (β-TCP), tetracalcium phosphate (TTCP), monocalcium phosphate monohydrate (MCPN), monocalcium phosphate anhydrous (MCPA), dicalcium phosphate dihydrate (DCPD), dicalcium phosphate anhydrous (DCPA), octacalcium phosphate (OCP), calcium dihydrogen phosphate, calcium dihydrogen phosphate hydrate, acid calcium pyrophosphate, anhydrous calcium hydrogen phosphate, calcium hydrogen phosphate hydrate, calcium pyrophosphate, calcium triphosphate, calcium phosphate tribasic, calcium polyphosphate, calcium metaphosphate, anhydrous tricalcium phosphate, tricalcium phosphate hydrate, amorphous calcium phosphate, or mixtures thereof.  
   
   
       50 . The prosthetic bone implant of  claim 48 , wherein at least a portion of the hardened calcium phosphate cement of the load bearing component and at least a portion of the hardened calcium phosphate cement of the porous component is made from tetracalcium phosphate.  
   
   
       51 . The prosthetic bone implant of  claim 41 , wherein at least a portion of the hardened calcium phosphate cement of the load bearing component and at least a portion of the hardened calcium phosphate cement of the porous component is made from tetracalcium phosphate and dicalcium phosphate anhydrous.  
   
   
       52 . The prosthetic bone implant of  claim 41 , wherein at least a portion of the hardened calcium phosphate cement of the load bearing component and at least a portion of the hardened calcium phosphate cement of the porous component is made from apatite.  
   
   
       53 . The prosthetic bone implant of  claim 52 , wherein the molar ratio of calcium/phosphate of the apatite is about 1.5-2.0.  
   
   
       54 . The prosthetic bone implant of  claim 41 , further comprising a transitional component coupling one or more porous components to the load bearing component, the transitional component comprising a hardened calcium phosphate cement.  
   
   
       55 . The prosthetic bone implant of  claim 54 , wherein the transitional component comprises a porosity gradient increasing from the porosity of the porous component to the porosity of the load bearing component.  
   
   
       56 . The prosthetic bone implant of  claim 41 , wherein the implant is adapted to allow body fluid and/or tissues to penetrate the implant when the implant is implanted into a patient.  
   
   
       57 . The prosthetic bone implant of  claim 41 , wherein the porous components are substantially surrounded by the load bearing component.  
   
   
       58 . The prosthetic bone implant of  claim 41 , wherein at least a portion of load bearing component and/or the porous components are exposed to the surface of the implant.  
   
   
       59 . The prosthetic bone implant of  claim 41 , wherein the configuration of the porous components relative to the load bearing component is such that, when the prosthetic bone implant is implanted into bone, at least a portion of the load bearing component is coupled to cortical bone, and at least a portion a porous component is coupled to cancellous bone.  
   
   
       60 . The prosthetic bone implant of  claim 41 , wherein at least a portion of the hardened calcium phosphate cement comprising the load bearing component and the porous component is made from tetracalcium phosphate, wherein at least a portion of tetracalcium phosphate particles comprises whiskers on the surface of the tetracalcium phosphate particles.  
   
   
       61 . The prosthetic bone implant of  claim 41 , wherein the configuration of the implant comprises a substantially cylindrical load bearing component with one or more holes extending through the longitudinal axis and with one or more porous components residing therein.