Threaded implants and methods of use across bone segments

Abstract

A threaded implant can be provided with an elongated main body having external threads configured to thread into bone, and an internal support structure located within the external threads. The internal support structure has a helical arrangement that extends in an opposite direction to the external threads. Other threaded implants and methods are also disclosed.

What is claimed is: 
     
         1 . A threaded implant comprising:
 an elongated main body having external threads configured to thread into bone; and   an internal support structure located within the external threads and having a helical arrangement that extends in an opposite direction to the external threads.   
     
     
         2 . The threaded implant of  claim 1 , further comprising a drive socket located on a proximal end of the main body and configured to receive a tip of a drive tool for rotationally driving the implant into bone. 
     
     
         3 . The threaded implant of  claim 1 , further comprising a through bore provided along a central longitudinal axis of the main body from a proximal end to a distal end. 
     
     
         4 . The threaded implant of  claim 1 , wherein the external threads have a single start and the internal support structure has four starts. 
     
     
         5 . The threaded implant of  claim 1 , wherein the internal support structure has a pitch that is eight time the pitch of the external threads. 
     
     
         6 . The threaded implant of  claim 1 , further comprising fenestrations or interstices between the external threads and the internal support structure, wherein the fenestrations or interstices are filled with a porous infill which provides scaffolding with increased surface area for new bone growth. 
     
     
         7 . The threaded implant of  claim 6 , wherein the porous infill is at least 20% more porous than the external threads and the internal support structure. 
     
     
         8 . A threaded implant comprising:
 an elongated main body having a proximal end, a mid-section and a distal end;   a first set of threads provided along the proximal end;   a second set of threads provided along the distal end; and   a sleeve located on the mid-section of the main body such that it may rotate with respect to the main body while being constrained from axial movement.   
     
     
         9 . The threaded implant of  claim 8 , wherein the sleeve has a transverse cross-section that is rectilinear. 
     
     
         10 . The threaded implant of  claim 8 , wherein the sleeve has a transverse cross-section having at least one apex. 
     
     
         11 . The threaded implant of  claim 8 , wherein the sleeve has a transverse cross-section that is triangular in shape. 
     
     
         12 . The threaded implant of  claim 8 , wherein the second set of threads has a pitch that is greater than a pitch of the first set of threads. 
     
     
         13 . A threaded implant comprising:
 an elongated main body having a proximal end, a mid-section and a distal end;   a head portion located on the proximal end of the main body and configured to abut against an outer surface of a bone segment; and   a threaded portion located on the distal end of the main body, wherein the threaded portion has a transverse cross-section that is triangular in shape.   
     
     
         14 . The threaded implant of  claim 13 , further comprising a drive socket located on the proximal end of the main body and configured to receive a tip of a drive tool for rotationally driving the implant into bone. 
     
     
         15 . A threaded implant comprising:
 an elongated main body having a proximal end, a mid-section and a distal end;   a proximal screw;   a proximal screw cap; and   at least one rotation stop.