Bone compression screw

Abstract

A system for orthopedic repair of bones, the system may include a compression screw. The screw may include a blunt tip on one end with tapped threads to allow for greater bone fixation uniform across a threaded portion of the screw. The screw may also include springs, which may be Belleville washers, which provide appropriate compression and tension and prevent excessive loosening of the screw after surgery. The springs allow the screw to retract without losing pressure on the fracture site. The system may be minimally invasive for multiple fractures on a single bone such as calcaneal fractures, and stabilizing long bone fractures without bone plates.

1 . A system comprising:
 a body comprising a shaft extending between a proximal portion and a distal portion;   wherein the proximal portion comprises a base and a head, wherein the proximal portion is configured to hold a spring between the base and the head, wherein both the base and the head each have a spring engaging surface;   wherein the base and head have a larger diameter than the shaft portion;   wherein the base comprises a bone engaging surface opposite the base spring engaging surface.   
     
     
         2 . The system of  claim 1 , wherein the distal portion comprises a blunt distal tip. 
     
     
         3 . The system of  claim 1 , wherein the base comprises a bore, wherein the base slidably engages the shaft, the shaft at least partially passing through the bore. 
     
     
         4 . The system of  claim 1 , wherein the base extends radially from and is freely slidable along the shaft. 
     
     
         5 . The system of  claim 1 , wherein the spring comprises a Belleville washer. 
     
     
         6 . The system of  claim 1 , wherein the spring comprises a plurality of Belleville washers. 
     
     
         7 . The system of  claim 6 , wherein the plurality of Belleville washers face the same direction. 
     
     
         8 . The system of  claim 1 , wherein the head comprises a bore configured to threadably engage a proximal end of the body, the head further comprising a polygonal shape configured to engage an insertion tool. 
     
     
         9 . A system comprising:
 a first portion and a second portion proximal to the first portion, the first portion comprising a first shaft extending between a first proximal portion and a first distal portion;   wherein the first proximal portion comprises a first base and a first head, wherein the first proximal portion is configured to hold a spring between the first base and the first head, wherein both the first base and the first head each have a spring engaging surface;   wherein the first base and first head have a larger diameter than the shaft portion; and   wherein the second portion comprises a second shaft extending between a second proximal portion and a second distal portion, wherein the second proximal portion comprises a second base, an intermediate component and a second head, wherein the second distal portion is configured to hold a spring between the second base and an intermediate component, wherein both the second base and the intermediate component each comprise a spring engaging surface;   wherein the second head is proximal the intermediate component.   
     
     
         10 . The system of  claim 9 , further comprising a rod engaged with and between the first portion and the second portion. 
     
     
         11 . The system of  claim 9 , wherein the intermediate component comprises external threads. 
     
     
         12 . The system of  claim 9 , wherein the first and second bases each extend radially from the first and second shafts respectively and threadably engage the first and second shafts respectively. 
     
     
         13 . The system of  claim 9 , wherein the spring comprises a Belleville washer. 
     
     
         14 . The system of  claim 9 , wherein the spring comprises a plurality of Belleville washers. 
     
     
         15 . The system of  claim 14 , wherein at least a portion of the Belleville washers face different directions. 
     
     
         16 . The system of  claim 9 , wherein the first head and the second head are each hexagonal and comprise a bore configured to threadably engage proximal ends of the first and second shafts respectively. 
     
     
         17 . A method of assembling a system comprising:
 engaging a base to a body of a screw by sliding the base onto the body of the screw from a proximal end of the screw toward a distal end of the screw, wherein the body comprises a shaft extending between a proximal portion and a distal portion, wherein the distal portion comprises threads extending radially from the shaft, the distal portion further comprising the distal end;   engaging a spring onto the body of the screw by sliding the spring from the proximal end toward the distal end;   positioning the spring proximal to the base;   positioning a head proximal to the springs;   engaging the head to the proximal end wherein the proximal end comprises threads recessed into the body, wherein the proximal end and the head comprise complementary threads.   
     
     
         18 . The method of  claim 17 , further comprising advancing the base toward the distal end, wherein the base comprises a bore, wherein the base slidably engages the shaft, the shaft at least partially passing through the bore. 
     
     
         19 . The method of  claim 18 , further comprising advancing the spring toward the distal end until the spring engages the base, wherein the spring comprises a plurality of Belleville washers. 
     
     
         20 . The method of  claim 19 , further comprising advancing the head toward the distal end until the head engages the spring, wherein the head comprises a threaded bore and the proximal end comprises recessed threads wherein the threaded bore is configured to threadably engage the proximal end of the body.