Cannulated distraction pin for fracture fixation

Abstract

An internal fixation pin comprises first and second portions with threads of different diameters, but having the same pitch and thread depth. The first portion includes a self-tapping tip. The opposite end is headless. A non-threaded shaft portion is frangibly connected to the second portion and is a mechanism for rotating the pin for threaded insertion into bone. A plurality of circumferentially spaced-apart longitudinal grooves are provided on the second portion adjacent its intersection with the shaft portion. The pin may be solid or cannulated. After insertion of the first and second portions across a fracture, the shaft portion is removed. The grooves permit engagement by a tool for rotation of the pin for removal should removal be necessary.

1 . A fracture fixation pin, comprising: 
 a) a first portion having a first diameter and first threads of a first thread diameter, said first portion having a tip at one end and a second end;    b) a second portion unitary with and extending from said second end of said first portion, said second portion having a second diameter larger than said first diameter, and second threads of a second thread diameter larger than said first thread diameter, said second threads extending in a same direction as said first threads; and    c) a non-threaded shaft portion unitary with and extending from said second portion, said shaft portion having a cross-sectional dimension which does not exceed a dimension of said second diameter, 
 wherein said first portion, said second portion, and said shaft portion are cannulated.  
   
   
   
       2 . A fracture fixation pin according to  claim 1 , wherein: 
 said first and second threads are continuous.    
   
   
       3 . A fracture fixation pin according to  claim 1 , wherein: 
 said tip includes a plurality of cutting flutes.    
   
   
       4 . A fracture fixation pin according to  claim 1 , wherein: 
 said tip is substantially conical and includes a surface angled at 30° relative to a longitudinal axis.    
   
   
       5 . a fracture fixation pin according to  claim 1 , wherein: 
 said first portion has a first length of approximately 2.55 inches and a first diameter of approximately 0.125 inch, and said second portion has a second length of approximately 0.6 inch and a second diameter of approximately 0.156 inch.    
   
   
       6 . A fracture fixation pin according to  claim 1 , wherein: 
 said shaft portion is substantially cylindrical.    
   
   
       7 . A fracture fixation pin according to  claim 1 , wherein: 
 said shaft is frangibly coupled to second portion.    
   
   
       8 . A fracture fixation pin according to  claim 1 , wherein: 
 a channel is provided about said pin between said second portion and said shaft portion.    
   
   
       9 . A fracture fixation pin according to  claim 1 , wherein: 
 said shaft has cross-sectional dimension smaller than said second diameter of said second portion.    
   
   
       10 . A fracture fixation pin according to  claim 1 , wherein: 
 said pin is headless.    
   
   
       11 . A fracture fixation pin according to  claim 1 , wherein: 
 all threads on said first portion have said first thread diameter.    
   
   
       12 . A fracture fixation pin according to  claim 1 , wherein: 
 said pin is made of metal.    
   
   
       13 . A fracture fixation pin according to  claim 1 , wherein: 
 said second portion is provided with a plurality of longitudinal grooves adjacent said shaft portion and spaced-apart about a circumference of said second portion.    
   
   
       14 . A fracture fixation pin according to  claim 13 , wherein: 
 said plurality of grooves includes exactly three grooves spaced apart 120° about said circumference of said second portion.    
   
   
       15 . A fracture fixation pin according to  claim 13 , wherein: 
 each of said grooves has a depth which interrupts said second threads.    
   
   
       16 . A fracture fixation pin, comprising: 
 a) a first portion having a first diameter and first threads of a first thread diameter, said first portion having a tip at one end and a second end; and    b) a second portion having a first end extending from and unitary with said second end of said first portion and a second free end, said second portion having a second diameter larger than said first diameter, and second threads of a second thread diameter larger than said first thread diameter, said first and second threads being continuous with each other and having a common pitch and thread depth, wherein said second free end is provided with a plurality longitudinal grooves spaced-apart about an outermost circumference of said second portion and extending crosswise through at least one of said second threads, 
 wherein said first and second portions are cannulated.  
   
   
   
       17 . A fracture fixation pin according to  claim 16 , wherein: 
 said plurality of grooves includes three grooves spaced apart 120° about said circumference of the second portion.    
   
   
       18 . A fracture fixation pin according to  claim 16 , wherein: 
 each of said grooves has a depth which extends below said second threads.