Method and instrumentation for patello-femoral joint replacement

Abstract

A patello-femoral joint prosthesis is provided which allows smooth tracking of the articulating surfaces through a full range of joint motion. A novel configuration of a femoral implant component that facilitates superior adhesion to bone is also provided. Also provided is a patello-femoral joint replacement system, which permits precise, reproducible bone preparation techniques that uniquely permit later revision and full knee joint replacement procedures with minimal complications. Also provided are a drill guide and a cutting guide, each being configured to provide three point stabilization during operation.

What is claimed is:  
     
         1 . A patello-femoral joint replacement device for implantation in a patient in need thereof comprising: 
 a femoral implant component, said femoral implant comprising a bone facing surface and an upper surface, said upper surface defining an articulating groove disposed along the longitudinal axis of said upper surface, said articulating groove having a distal terminus that is configured to have a superior angled upturn, and    a patellar implant component comprising a securing surface oppositely disposed to an articulating surface, said articulating surface being in a slidable articulation with said articulating groove of said femoral implant,    wherein said device has full range of motion of the patello-femoral joint.    
     
     
         2 . The device of  claim 1 , wherein said femoral implant articulating groove has a generally concave configuration longitudinally oriented along said articulating groove and said patellar implant articulating surface has a generally convex configuration that is generally complementary to said articulating groove.  
     
     
         3 . The device of  claim 1 , wherein said bone facing surface comprises a circumferentially disposed undercut edge along at least a portion of the outer most rim of the femoral implant.  
     
     
         4 . The device of  claim 1 , wherein said bone facing surface comprises at least one recessed pocket sized and configured to receive a portion of adhesive material, said recessed pocket providing additional surface area and improved adhesion when said device is implanted against a bone surface.  
     
     
         5 . The device of  claim 1 , wherein said femoral implant bone facing surface comprises a roughened surface.  
     
     
         6 . The device of  claim 5 , wherein said roughened surface comprises at least one spike or peg.  
     
     
         7 . The device of  claim 5 , wherein said roughened surface comprises a porous coating.  
     
     
         8 . The device of  claim 1 , wherein said securing surface of said patellar implant comprises at least one bone anchor member, sized and configured for insertion into a bone.  
     
     
         9 . The device of  claim 8 , wherein said bone anchor member comprises an annular retaining groove circumferentially disposed around said bone anchor member.  
     
     
         10 . The device of  claim 8 , wherein said patellar securing surface further comprises at least one peg in addition to said bone anchor member.  
     
     
         11 . The device of  claim 1 , wherein said femoral implant bone facing surface further comprises an intramedulary stem, said stem being sized and configured for insertion into the femoral canal of a patient.  
     
     
         12 . A patello-femoral joint replacement system comprising a patello-femoral joint replacement device, a cutting guide for precisely guiding the use of a bone saw for cutting of the anterior surface of a femur of a patient, and a drill guide for precisely guiding the insertion of a bone drilling bit into the femur of a patient.  
     
     
         13 . The system of  claim 12 , further comprising a feeler gauge sized and configured to facilitate positioning of said cutting guide so as to accurately position a bone saw prior to the user cutting bone therewith.  
     
     
         14 . The system of  claim 12 , further comprising a bone rasp sized and configured to be inserted into a surgical opening in a patient undergoing patello-femoral joint replacement and at least partially textured so as to provide an abrasive surface for preparing a bone for receiving said patello-femoral joint replacement device.  
     
     
         15 . The system of  claim 12 , wherein said drill guide comprises a drill guide block for positioning against a bone to be drilled, said drill guide block defining a drill guide passage which is sized and configured to slidably guide a drill bit from an entrance on one side of said drill guide block through and out of the opposite side of said drill guide block, said drill guide block providing a stable guide to facilitate drilling an intramedullary canal.  
     
     
         16 . The system of  claim 15 , wherein said drill guide block is provided with a handle configured to permit a user to position said drill guide block during operation.  
     
     
         17 . The system of  claim 15 , wherein said drill guide block is provided with a drill guide stylus, said drill guide stylus being sized and configured to provide a referencing contact between the anterior surface of a femur of a patient and a drill guide stylus-femoral contact point located at the proximal end of said drill guide stylus, said drill guide stylus providing stability for said drill guide block during operation of said drill guide.  
     
     
         18 . The system of  claim 17  wherein said drill guide block is provided with at least one drill guide positioning point projecting from the surface of the drill guide block which is placed against the bone during operation, said positioning point providing a additional stabilizing means for said drill guide.  
     
     
         19 . The system of  claim 12 , wherein said cutting guide comprises: 
 an intramedullary rod sized and configured to be insertable into an intramedullary canal provided in the femur of a patient, said intramedullary rod having at least one groove provided in its surface and oriented along the longitudinal axis of said intramedullary rod,    a cutting guide member which is connected to a proximal end of said intramedullary rod, said cutting guide member being bifurcated along the longitudinal axis of said cutting guide member so as to define a cutting guide slot, which is sized and configured to slidably guide a bone saw during operation of said cutting guide, and    a stylus arm movably connected to the proximal end of said cutting guide and sized and configured to provide a stabilizing contact point between a stylus-femoral contact point of said stylus arm and the anterior surface of a femur of a patient.    
     
     
         20 . The system of  claim 19 , wherein said cutting guide includes at least one anchor guide which defines a respective anchor guide portal, said at least one anchor guide being positioned on the saw guide member so as to provide anchoring points through which a surgeon can drill anchoring holes in the bone of the patient and can affix anchors through said anchor guide portal into said bone of the patient to provide stability during operation, said stylus arm and said anchor guide providing multiple stabilization points for said cutting guide.  
     
     
         21 . A kit for use in implanting a patello-femoral joint replacement device in a patient, said kit comprising: 
 a petallo-femoral joint replacement device,    a drill guide for stabilizing and positioning a drill bit in the operation of drilling an intramedullary canal in the femur of a patient, and    a cutting guide for stabilizing and positioning a bone saw blade in the operation of providing a cut to the anterior surface of the femur of a patient.    
     
     
         22 . The kit of  claim 21 , further comprising a bone rasp, for preparing the surface of a femur of a patient to receive said petallo-femoral joint replacement device.  
     
     
         23 . The kit of  claim 22 , further comprising an impactor for forcibly inserting components of said drill guide, said cutting device, and said patello-femoral joint replacement device into the prepared surface of the femur of a patient.  
     
     
         24 . A method of implanting a patello-femoral joint replacement device in a patient in need of such joint replacement, the method comprising: 
 providing a drill guide, a cutting guide having an intramedullary rod component, and a patello-femoral joint replacement device, said replacement device having a femoral implant component and a patellar implant component,    surgically exposing the patello-femoral joint of said patient,    securing said drill guide to the distal end of the femur of a patient and using said drill guide to precisely position a drill bit in relation to said femur,    using said drill bit to prepare an intramedullary canal in said femur,    removing said drill bit and drill guide,    securing said cutting guide to said femur by insertion of said intramedullary rod into said intramedullary canal of said femur so as to provide a precise guide for a cutting bone cutting instrument,    cutting the anterior surface of the femur so as to prepare said anterior surface to have a substantially flat prepared surface and removing said cutting guide from said patient,    implanting said femoral implant component into said prepared anterior surface of said femur,    implanting said patellar implant component into said patient so as to provide a slidably articulating joint between said femoral implant component and said patellar implant component.