Telescoping Bone Screw

Abstract

A bone screw for treating a bone fracture having a detent assembly on a body portion thereof. The detent assembly includes a detent member that is movable between a first and second position. The detent assembly operative to secure the body whereby said plunger portion moves independent of said body. The bone screw may also include a plunger assembly having a plunger with a threaded portion and a plunger portion. The plunger portion is slidably disposed within a chamber of the body.

1 . An apparatus for repairing a bone fracture comprising:
 a body; and   a detent assembly on said body, said detent assembly movable between a first and a second position wherein positioning said detent assembly in said second position operates to secure said body from movement relative to a bone nail.   
     
     
         2 . An apparatus as set forth in  claim 1  including a detent member and a drive member, said drive member operative to engage said detent member and move said detent member towards said second position. 
     
     
         3 . An apparatus as set forth in  claim 3  wherein said drive member includes a threaded portion. 
     
     
         4 . An apparatus as set forth in  claim 3  including said body having a threaded portion, said threaded portion of said drive member engaging said threaded portion of said body wherein rotation of said drive member moves said detent member towards said second position. 
     
     
         5 . An apparatus as set forth in  claim 1  wherein said second position of said detent member includes at least a portion of said detent member extending above an outer surface of said body. 
     
     
         6 . Apparatus as set forth in  claim 1  wherein said detent member includes an outer surface, said outer surface engaging the bone nail, said outer surface configured to increase the holding force and correspondingly reduce movement of the body with respect to the bone nail. 
     
     
         7 . An apparatus as set forth in  claim 6  including said detent member having a plurality of grooves. 
     
     
         8 . An apparatus as set forth in  claim 6  including a surface finish located on said outer surface. 
     
     
         9 . An apparatus as set forth in  claim 2  wherein said detent member includes a lock ring and said drive member includes a lock sleeve; and
 each of said lock ring and said lock sleeve disposed on said body. 
 
     
     
         10 . An apparatus as set forth in  claim 9  including said lock ring having a beveled surface and said lock sleeve having a beveled surface, said beveled surface of said lock ring engaging said beveled surface of said lock sleeve. 
     
     
         11 . An apparatus as set forth in  claim 9  including:
 said lock ring having a first beveled surface and a second beveled surface; 
 said body having a beveled surface; and 
 said lock sleeve having a beveled surface wherein said first beveled surface of said lock ring engages said beveled surface of said body and said second beveled surface of said lock ring engages said beveled surface of said lock sleeve. 
 
     
     
         12 . An apparatus as set forth in  claim 11  wherein said lock ring includes an outer surface and a plurality of grooves located in said outer surface. 
     
     
         13 . An apparatus as set forth in  claim 9  including:
 said body having a threaded portion; 
 said lock sleeve having a tubular configuration and a plurality of internal threads, said threaded portion of said lock sleeve engaging said threaded portion of said body wherein rotation of said lock sleeve moves said lock ring outwardly past an outer peripheral surface of the body and towards said second position. 
 
     
     
         14 . An apparatus as set forth in  claim 1  wherein said detent assembly includes:
 a lock ring having a first beveled surface and a second beveled surface; 
 a lock sleeve having a beveled surface; and 
 said body having a shaft portion and a beveled surface, said lock ring located on said shaft portion and said first beveled surface of said lock ring engaging said beveled surface of said body and said lock sleeve located on said shaft portion and said second beveled surface of said lock ring engaging said beveled surface of said lock sleeve. 
 
     
     
         15 . An apparatus as set forth in  claim 14  wherein said shaft portion includes a threaded portion and said lock sleeve includes a threaded portion, said threaded portion of said lock sleeve engaging said threaded portion of said shaft portion wherein rotation of said lock sleeve moves said lock ring outwardly past an outer peripheral surface of said body and towards said second position. 
     
     
         16 . A bone screw for use in combination with a bone nail to treat a bone fracture comprising:
 a body, said body having a socket formed in one end thereof and a plunger assembly disposed in said socket;   an annular member located on said body, said annular member movable between a first and a second position wherein said second position of said annular member operates to secure said body from movement relative to the bone nail; and   a tubular member located on said body and operative to engage said annular member and move said annular member towards said second position.   
     
     
         17 . A bone screw as set forth in  claim 16  including:
 said body having a shaft portion, said annular member located on said shaft portion and said tubular member located on said shaft portion wherein said tubular member engages said annular member. 
 
     
     
         18 . A bone screw as set forth in  claim 17  including:
 said annular member including a lock ring having a first beveled surface and a second beveled surface; 
 said tubular member including a lock sleeve having a beveled surface; and 
 said body having a beveled surface, said first beveled surface of said lock ring engaging said beveled surface of said body and said second beveled surface of said lock ring engaging said beveled surface of said lock sleeve. 
 
     
     
         19 . A bone screw as set forth in  claim 18  wherein said shaft portion includes a threaded portion and said lock sleeve includes a threaded portion engaging said threaded portion of said shaft portion such that rotation of said locking sleeve about said shaft portion moves said detent member towards said second position. 
     
     
         20 . A bone screw as set forth in  claim 19  including a plunger assembly, said plunger assembly including a threaded plunger disposed in a socket formed in one end of said body;
 a spring member located between said threaded plunger and said body; and 
 a detent mechanism, said detent mechanism enabling relative movement between said plunger and said body in one direction and limiting relative movement between said plunger and said body in an opposite direction. 
 
     
     
         21 . A bone screw as set forth in  claim 20  wherein said detent mechanism includes a ratchet. 
     
     
         22 . A bone screw as set forth in  claim 21 , said ratchet including:
 a plurality of teeth associated with said socket; and   a plurality of teeth associated with said plunger wherein said plurality of teeth associated with said socket cooperate with said plurality of teeth associated with said plunger to limit travel of said plunger in one direction only.