Implantable screw for stabilization of a joint or a bone fracture

Abstract

A bone screw has a flexible shaft which prevents relative movements in the direction of tension, but permits smaller movements in all other directions, and wherein the bone screw is configured as a screw insertable into medullary cavities having a curved surface, where the screw adapts to the given contour.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and their equivalents:  
     
         1 . An implantable screw for stabilization of a joint or a bone fracture comprising an elongated body with a proximal head portion and a distal insertion portion having a thread, wherein the head portion and the insertion portion are interconnected by a flexible shaft.  
     
     
         2 . The implantable screw of  claim 1  wherein the proximal head portion is provided with a thread.  
     
     
         3 . The implantable screw of  claim 2 , wherein the threads of the proximal head portion and the distal insertion portion are identical.  
     
     
         4 . The implantable screw of  claim 1 , wherein the thread of the distal insertion portion is a bone thread.  
     
     
         5 . The implantable screw of  claim 3 , wherein the thread of each the head portion and the insertion portion are a bone thread  
     
     
         6 . The implantable screw of  claim 1 , wherein the body is defined by a planar axial moment of inertia which is 30 percent less than that of a conventional screw.  
     
     
         7 . The implantable screw of  claim 1 , wherein the planar axial moment of inertia is 50 percent less than that of a conventional screw of same outer diameter.  
     
     
         8 . The implantable screw of  claim 1 , wherein the flexible shaft is a member selected from the group consisting of a wire cable, a wire bundle, a cord, a spiral, multiple webs and fibers.  
     
     
         9 . The implantable screw of  claim 1 , wherein the flexible shafts is provided with a reinforcement.  
     
     
         10 . The implantable screw of  claim 9 , wherein the reinforcement is a sleeve for sliding onto the shaft.  
     
     
         11 . The implantable screw of  claim 10 , wherein the sleeve is configured as a spiral.  
     
     
         12 . The implantable screw of  claim 1 , wherein the threaded insertion portion is configured as a stud bolt with a wrench socket and provided with a threaded bolt with a head nut in an area of the head portion.  
     
     
         13 . The implantable screw of  claim 1 , wherein the head portion is provided with a wrench socket and configured with a smooth surface.  
     
     
         14 . The implantable screw of  claim 2 , wherein the head portion has a diameter which is greater than a diameter of the insertion portion, and has a smaller thread pitch than a thread pitch of the insertion portion.  
     
     
         15 . The implantable screw of  claim 1 , wherein the head portion and the insertion portion are each provided with a wrench socket.  
     
     
         16 . The implantable screw of  claim 1 , wherein the screw is made from a material selected from the group consisting of biocompatible metal, biocompatible absorbable plastic, biocompatible non-absorbable plastic and a combination thereof.