Apparatus and method for reconstructing ligaments

Abstract

Apparatus for removing bone from a femoral notch, or the like, which includes a guidewire and a router assembly. The router assembly comprises a cutting head fixed to a shaft rotatably disposed in a hole through a body portion of a shield assembly. A hood portion of the shield assembly extends from the body portion of the shield assembly and covers a first portion of the cutting head while leaving exposed a second portion of the cutting head. The guidewire extends through a hole in the shaft, a hole in the cutting head, and a hole in the shield assembly hood portion, such that the router assembly is movable along the guidewire. The shaft is rotatable in the shield assembly body portion such that the second portion of the cutting head is engageable with the bone and operative to remove portions of the bone. The guidewire is installed in the knee so that it extends along the length to be occupied by a graft ligament. The guidewire and router assembly are flexible so that the bone-trimming operation may be conducted dynamically as the knee is moved through a range of natural motions.

What is claimed is:  
     
         1 . Apparatus for removing portions of a bone, said apparatus comprising: 
 a router assembly comprising: 
 a cutting head fixed to a shaft; and  
 a shield assembly having a body portion and a hood portion, said body portion having a hole therethrough for receiving said shaft, said hood portion extending from one end of said body portion and defining a concavity in which is disposable in part said cutting head.  
   
     
     
         2 . Apparatus according to  claim 1  wherein said cutting head and said shaft are provided with bores in alignment with each other and adapted to receive a guidewire therethrough.  
     
     
         3 . Apparatus according to  claim 2  wherein said hood portion is provided with a hole therein alignable with said cutting head bore and adapted to receive said guidewire.  
     
     
         4 . Apparatus according to  claim 3  wherein said body portion is cylindrically shaped and said body portion hole extends lengthwise of said cylindrically shaped body portion and removed from a central axis of said body portion.  
     
     
         5 . Apparatus according to  claim 4  wherein said shield portion encloses a first portion of said cutting head, and a second portion of said cutting head extends outwardly from said shield portion.  
     
     
         6 . Apparatus according to  claim 5  wherein a portion of the perimeter of said second portion of said cutting head is substantially aligned with a portion of the perimeter of said body portion.  
     
     
         7 . Apparatus according to  claim 5  wherein said first portion of said cutting head includes a majority of the circumference of said cutting head.  
     
     
         8 . Apparatus according to  claim 3  wherein said apparatus further comprises: 
 the guidewire, said guidewire extending through said shaft, said cutting head and said shield hood portion hole, said shaft, said cutting head, and said shield assembly being movable along said guidewire to advance said router assembly along said guidewire.  
 
     
     
         9 . Apparatus according to  claim 5  wherein said shield assembly body portion comprises a collar within a sleeve, said body portion hole extending through said collar.  
     
     
         10 . Apparatus according to  claim 1  wherein at least a portion of said shaft is flexible.  
     
     
         11 . Apparatus according to  claim 1  wherein at least a portion of said shield assembly is flexible.  
     
     
         12 . Apparatus according to  claim 11  wherein at least a portion of said body portion is flexible.  
     
     
         13 . Apparatus according to  claim 1  wherein said apparatus further comprises: 
 the guidewire, said guidewire being formed out of a pseudoelastic material.  
 
     
     
         14 . Apparatus for removing portions of a bone, said apparatus comprising: 
 a guidewire; and    a router assembly;    said router assembly comprising a cutting head fixed to a shaft rotatably disposed in a hole through a body portion of a shield assembly, and a hood portion of said shield assembly extending from said body portion of said shield assembly and covering a first portion of said cutting head while leaving exposed a second portion of said cutting head;    said guidewire extending through a bore in said shaft, a bore in said cutting head, and a hole in said shield assembly hood portion, such that said router assembly is movable along said guidewire and said shaft is rotatable in said shield assembly body portion, such that said second portion of said cutting head is engageable with the bone and is operative to remove portions of the bone.    
     
     
         15 . Apparatus for removing portions of a bone, said apparatus comprising a cutting head fixed to a shaft, and a guidewire extendible through a bore extending through said shaft and said cutting head, such that said cutting head is movable along said guidewire, said cutting head being devoid of cutting means on a first portion of the periphery thereof and having cutting means on a second portion of the periphery thereof, said second portion of said cutting head being engageable with the bone portions to be removed, said shaft and cutting head being rotatably movable in an oscillating fashion such that said cutting head second portion moves in alternating opposite directions across the bone portions to remove portions thereof, said first portion being smooth and non-destructive with respect to anatomical structures with which said first portion comes into contact.  
     
     
         16 . Apparatus for removing portions of a bone, said apparatus comprising a cutting head fixed to a shaft, and a guidewire extendible through a bore extending through said shaft and said cutting head, such that said cutting head is movable along said guidewire, said cutting head being adapted to cut bone coming into engagement with said cutting head but to leave unharmed soft tissue coming into contact with said cutting head.  
     
     
         17 . Apparatus for marking portions of bone subsequently to be removed, said apparatus comprising a marker head fixed to a shaft, and a guidewire extendible through a bore extending through said shaft and said marker head, such that said marker head is movable along said guidewire, said marker head being adapted to hold a dye and release the dye upon contact with a bone, thereby to mark the portions of the bone proximate said guidewire as said marker head moves along said guidewire.  
     
     
         18 . Apparatus according to  claim 17  further comprising a fixture for disposal in a bone tunnel, with a distal end of said guidewire pivotally attached to said fixture and movable about the pivotal connection such that said guidewire can extend from said fixture at an angle to a lengthwise central axis of said fixture.  
     
     
         19 . Apparatus for marking bone portions for subsequent removal, the apparatus comprising: 
 a marker assembly comprising: 
 a marker head fixed to a shaft and adapted to hold and release a dye;  
 said shaft and said marker head having bores therethrough;  
   and said apparatus further comprising: 
 a guidewire for passing through said shaft bore and said marker head bore to support said marker assembly which is movable on said guidewire to engage bone portions proximate said guidewire and mark said bone portions for said subsequent removal.  
   
     
     
         20 . A method for removing portions of a bone, said method comprising the steps of: 
 providing (i) a guidewire, and (ii) a router assembly comprising a cutting head fixed to a shaft rotatably disposed in a hole through a body portion of a shield assembly, and a hood portion of said shield assembly extending from said body portion of said shield assembly and covering a first portion of said cutting head while leaving exposed a second portion of said cutting head, said shaft and said cutting head having bores therethrough, and said shield assembly hood portion having a hole therein;    anchoring said guidewire in the bone;    mounting said router assembly on said guidewire such that said guidewire extends through said shaft bore, said cutting head bore, and said hood portion hole, and moving said router assembly along said guidewire to proximate the bone;    positioning said router assembly such that said second portion of said cutting head is directed toward the bone portion to be removed, and rotating said shaft, to rotate said cutting head, to remove portions from the bone, while the shield assembly hood portion separates said cutting head from other anatomical structures.    
     
     
         21 . A method according to  claim 20  wherein a distal end of said guidewire is pivotally connected to a fixture and said fixture is anchored in a tunnel in the bone to thereby anchor said guidewire in the bone.  
     
     
         22 . A method for reconstructing an anterior cruciate ligament (ACL) of a patient using a graft ACL, said method comprising the steps of: 
 extending the patient's knee at an angle of approximately 90°;    forming a bone tunnel in the patient's tibia;    passing a guidewire through said tibial bone tunnel and into the patient's femur, said guidewire being positioned so as to extend along the length where the graft ACL will thereafter reside;    positioning a cannulated router device onto said guidewire;    performing notchplasty on said femur using said cannulated router device as said cannulated router device is mounted on said guidewire and as said knee is moved through a range of natural motions; and    dismounting said cannulated router device from said guidewire.    
     
     
         23 . A method according to  claim 22  wherein said method comprises the further steps of: 
 forming a bone tunnel in said femur;  
 removing said guidewire from said femur; and  
 installing the graft ACL in said femoral bone tunnel and said tibial bone tunnel.