Internal cord fixation device

Abstract

Methods and apparatuses for fixing a bone fragment or a bone prosthesis onto a bone. To affix a bone fragment to the bone, an internal fastener is attached from within the interior of the bone to a bone fragment with a length of flexible, inelastic cord extending within the bone interior and attached to the fastener and passing outwardly through an opening in a second bone fragment. The fastener and cord are so positioned as to draw respective fracture surfaces together to reduce the fracture when the cord is pulled outwardly of the opening in the second bone fragment. A second fastener desirably is attached to the bone opening, this fastener including an open bore to receive the cord and a lock to secure the cord to this fastener and maintain the cord under tension.

I claim:  
     
         1 . An orthopedic fixation system for fixing a bone to an element which is a bone fragment or a prosthesis, comprising a length of flexible, inelastic cord, a first fastener for attaching the cord to said element; a second fastener for fastening the cord to the bone, at least one of the fasteners having an opening through which the cord may pass from the interior of the bone to the exterior to enable said element to be securely mounted to the bone portion.  
     
     
         2 . An orthopedic fixation system comprising a bone having an exterior cortical portion and a non-cortical interior, an element which is a prosthesis or a bone fragment, a length of inelastic, flexible cord; a first fastener attaching the cord to said element, a second fastener attaching the cord to the bone, the cord extending from said first fastener within the interior of the bone to the second fastener.  
     
     
         3  The orthopedic fixation system of  claim 2  wherein at least one of said fasteners includes an opening through which said cord passes from the interior of the bone to the exterior, said at least one fastener including a lock for locking the cord to the fastener through which it passes.  
     
     
         4 . The orthopedic fixation system of  claim 3  wherein at least one of said fasteners includes a threaded portion adapted to be screwed into bone.  
     
     
         5 . The orthopedic fixation system of  claim 2  wherein said element is a bone fragment resulting from a fracture of said bone, said bone fragment and bone having mating fracture surfaces that are prevented from separating by said cord extending between them.  
     
     
         6 . The orthopedic fixation system of  claim 5  wherein at least one of said fasteners includes an elongated toggle portion adapted to pass in a generally coaxial direction through a bore formed in said bone or bone fragment and to assume a position generally normal to said axis against an outer surface of said bone or bone fragment.  
     
     
         7 . The orthopedic fixation system of  claim 5  wherein at least one of said fasteners includes a threaded portion adapted to be screwed into bone.  
     
     
         8 . The orthopedic fixation system of  claim 5  wherein at least one of said fasteners includes a bone plate adapted to engage a bone surface.  
     
     
         9 . The orthopedic fixation system of  claim 5  including a third fastener fastenable to bone and having a surface within said interior over which said cord may be movably trained to change the direction of said cord between the first and second fasteners.  
     
     
         10 . The orthopedic fixation system of  claim 5  wherein at least one of said fasteners includes an opening through which said cord passes from the interior of the bone to the exterior, said at least one fastener including a lock for locking the cord to the fastener through which it passes.  
     
     
         11 . The orthopedic fixation system of  claim 10  wherein said opening comprises a bore at least partially threaded and within which the cord extends, and wherein said lock comprises a threaded member threadingly received in the bore and capable of engaging said cord to restrain cord movement.  
     
     
         12 . The orthopedic fixation system of any one of claims  2 - 11  including a tensioning instrument adapted to contact the cord and at least one of said fasteners to place the cord in tension by drawing said cord outwardly through said fastener.  
     
     
         13 . A bone fracture reduction system for reducing and promoting healing of a bone fracture, comprising a bone normally having an exterior cortical portion and a non-cortical interior, the bone having bone fragments with generally confronting fracture surfaces, an internal fastener attached from within said interior to a first bone fragment, a length of flexible, inelastic cord extending within said bone interior and attached to said internal fastener and passing outwardly through an opening in a second bone fragment, said internal fastener and cord being so positioned as to draw respective fracture surfaces together to reduce said fracture upon tensioning of the cord extending outwardly through said opening.  
     
     
         14 . The bone fracture reduction system of  claim 13  including a lock locking the cord to said second fragment.  
     
     
         15 . The bone fracture reduction system of  claim 14  wherein said interior fastener includes a threaded portion screwed into said cortical portion from within said bone interior.  
     
     
         16 . The bone fracture reduction system of  claim 13  wherein said first bone fragment has an outer, cortical surface and wherein said first fastener includes an elongated toggle supported against said outer surface portion.  
     
     
         17 . The bone fracture reduction system of  claim 13  including an external fastener attached to said second fragment and having a hollow interior through which said cord extends.  
     
     
         18 . The bone fracture reduction system of  claim 17  wherein said hollow interior of the second fastener is at least partially threaded, and wherein said lock comprises a threaded member threadingly received in said hollow interior, said cord being operatively grasped between said threaded member and said hollow interior to restrain cord movement within said second fastener.  
     
     
         19 . The bone fracture reduction system of  claim 17  wherein said bone is a long bone having a medullary cavity, said internal fastener being carried attached from within the medullary canal to one of the bone fragments and said length of flexible, inelastic cord extending from said internal fastener through said external fastener across a fracture interface and more closely adjacent one side of said medullary canal than the other side thereof, the bone fracture reduction system including a second flexible, inelastic cord and an external fastener attached to said second fragment and through which said second cord extends, said second cord being arranged on generally the opposite side of said medullary canal from said first cord, whereupon said cords may be independently adjusted so as to resist bending moments applied at the transverse fracture site.  
     
     
         20 . The bone fracture reduction system of  claim 19  wherein said internal fastener comprises a pair of fasteners each having threaded portions threaded into said first bone fragment on opposite sides of the medullary canal.  
     
     
         21 . The bone fracture reduction system of  claim 19  wherein said internal fastener comprises an elongated fastener adapted for insertion and capture within the medullary canal of the first bone fragment with said cords extending from said fastener adjacent opposite sides of the intermedullary canal.  
     
     
         22 . The bone fracture reduction system of  claim 13  wherein said one bone fragment has a bore extending through its cortical portion and wherein said second fastener includes a plate adapted to engage the outer surface of the cortical portion.  
     
     
         23 . The bone fracture reduction system of  claim 13  including a third fastener fastened from the interior of said bone to a third bone fragment and having a pulley surface over which said cord is movably trained to change the direction of said cord within the interior of said bone.  
     
     
         24 . The bone fracture reduction system of  claim 13  including a plurality of internal fasteners attached from within said bone interior to different ones of said bone fragments, said fasteners and cord being so positioned as to draw respective fracture surfaces of said bone fragments together to reduce said fracture upon tensioning of the cord extending outwardly through said opening.  
     
     
         25 . The bone fracture reduction system of  claim 23  wherein at least one of said interior fasteners includes a pulley surface over which said cord is movably trained to change the direction of said cord within the interior of said bone.  
     
     
         26 . The bone fracture reduction system of  claim 23  wherein each of said interior fasteners includes a pulley surface over which said cord is movably trained to change the direction of said cord within the interior of said bone.  
     
     
         27 . Method for positioning fragments of a bone fracture with respect to each other to reduce the fracture and promote healing of a bone which normally has an exterior cortical portion and a non-cortical interior, the bone fragments having confronting fracture surfaces forming a fracture interface, the method comprising attaching from within the interior of the bone to a first bone fragment an internal fastener to which is attached a length of flexible, inelastic cord, drawing said cord through a bore formed in a second bone fragment to draw said fragments together in a direction to relieve the fracture.  
     
     
         28 . The method of  claim 27  including the step of securing the cord to said second bone fragment to restrain separation of the bone fragments at the fracture interface.  
     
     
         29 . The method of  claim 27  including the step of determining the direction of tensile force desired to draw said fracture surfaces toward each other, and positioning said cord parallel to said direction.  
     
     
         30 . The method of  claim 27  wherein said internal fastener has a threaded end, the method including the step of screwing said threaded end from the interior of said bone into a cortical portion of said first bone segment.  
     
     
         31 . The method of  claim 27  wherein said internal fastener has an elongated toggle portion, the method including the step of forming a bore through said first bone fragment, and passing said toggle from the interior of the bone through said bore to enable the toggle to lie against a cortical outer surface of said first bone fragment.  
     
     
         32 . The method of  claim 27  including the step of attaching to the second bone fragment an external fastener through which the cord can be drawn, and locking the cord to the latter fastener.  
     
     
         33 . The method of  claim 32  including the step of providing a tensioning instrument having a first portion grasping said cord and a second portion in contact with said external fastener, and operating said instrument so as to separate said portions and to place said cord in tension.  
     
     
         34 . The method of  claim 27  comprising attaching a plurality of internal fasteners to different ones of a plurality of bone fragments, said internal fasteners having attached to them said length of flexible cord, said internal fasteners being so positioned with respect to each other that when said cord is tensioned, said fragments are drawn together in directions to reduce the fracture.  
     
     
         35 . The method of  claim 34  wherein at least one of said interior fasteners includes a pulley surface over which said cord is movably trained to change the direction of said cord within the interior of said bone, the method including the step of pulling said cord over said pulley surface.  
     
     
         36 . The method of  claim 34  wherein each of said interior fasteners includes a pulley surface over which said cord is movably trained to change the direction of said cord within the interior of said bone, the method including the step of pulling said cord over said pulley surfaces.  
     
     
         37 . Method for reducing a bone fracture in a bone having a cortical exterior portion and a non-cortical interior, said fractured bone having at least three bone fragments in which first and second fragments have first mating fracture surfaces and second and third bone fragments have second, different mating fracture surfaces, the method comprising attaching one end of a length of flexible cord from within the bone interior to the first bone fragment, attaching a pulley bearing said cord to the second bone fragment, the other end of said cord passing outwardly of the bone through an opening in the third bone fragment, tensioning said cord to draw together said mating fracture surfaces to relieve the fractures, and securing said tensioned cord to said third bone fragment.  
     
     
         38 . Method for reducing a bone fracture comprising at least two pairs of bone fragments, a first pair of bone fragments having first mating fracture surfaces and a second pair of bone fragments having second, different mating fracture surfaces, and wherein one bone fragment may be common to each of the first and second pairs, the bone having an exterior cortical portion and an interior non-cortical portion, the method comprising 
 a. attaching one end of a length of flexible cord from the interior of the bone to one fragment of said first pair, said cord extending through an opening in the other bone fragment of said first pair in a direction so that when said cord is placed in tension, the first mating fracture surfaces are drawn toward each other;    b. attaching one end of a second length of flexible cord from the interior of the bone to one fragment of said second pair, said second length of cord extending through an opening in the other bone fragment of said second pair in a direction so that when said cord is placed in tension, the second mating fracture surfaces are drawn toward each other; and    c. appropriately adjusting tension in said cords with respect to each other to reduce the fracture surfaces.    
     
     
         39 . The method of  claim 38  including the step of securing the tensioned cords to said other bone fragments.  
     
     
         40 . Method for reducing a bone fracture of a bone having a cortical exterior portion and a non-cortical interior, the fracture comprising at least three bone fragments each having fracture surfaces mating with fracture surfaces of the other fragments, the method comprising: 
 a. attaching from the interior of the bone to each of two of said bone fragments a fastener having a pulley surface over which is trained a length of flexible cord;    b. drawing said cord through an opening in a third bone fragment and tensioning said cord to draw said fracture surfaces together; and    c. securing said cord to said third bone fragment to respect to each other to reduce the fracture surfaces.    
     
     
         41 . Method for reducing a bone fracture of an elongated bone having a medullary canal and a generally transverse fracture dividing the bone into first and second bone fragments, comprising 
 a. attaching from the interior of the bone to one of said bone fragments an internal fastener from which extends at least two flexible, inelastic cord lengths;    b. drawing said cord lengths through openings formed in said second bone fragment at spaced positions along the interior of the medullary canal of that fragment so that said cord lengths are spaced from one another within the medullary canal at the fracture site; and    c. securing said cords to said second bone fragment to reduce the fracture surfaces, said spaced cords resisting bending moments at the fracture site.    
     
     
         42 . A bone fracture reduction system for use in reducing a fracture of a long bone producing first and second bone fragments, comprising an internal fastener adapted for insertion and capture within the medullary canal of one bone fragment, a pair of flexible, inelastic cords attached at laterally spaced points to and extending from said internal fastener, and a pair of spaced external fasteners attachable to the other of said bone fragments and having openings through which said cords may respectively pass on opposite sides of the medullary canal, whereby said cords may traverse the fracture site within the medullary canal on opposite sides thereof to resist bending moments at the fracture site.