Fluted intramedullary stem

Abstract

An intramedullary stem that provides enhanced distal fixation and flexibility and methods for implanting the stem. Certain embodiments of the stem have primary and secondary flutes (or ridges or wedges). Other embodiments have transitional regions.

1 - 12 . (canceled) 
   
   
       13 . An intramedullary implant, comprising:
 (a) a stem having a shaft with a proximal end, a distal end, and a longitudinal length;   (b) primary flutes disposed along at least a portion of the longitudinal length, the primary flutes having (i) a cross-sectional taper, (ii) substantially parallel-sides, or (iii) a combination thereof, and wherein at least a portion of the flutes have a narrowing apex from the proximal end to the distal end.   
   
   
       14 . The intramedullary implant of  claim 13 , wherein the primary flutes define an outer profile that is substantially cylindrical at at least some point and a tapered core. 
   
   
       15 . The intramedullary implant of  claim 13 , further comprising:
 (c) secondary flutes disposed along at least a portion of the longitudinal length, the secondary flutes having (i) a cross-sectional taper, (ii) substantially parallel-sides, or (iii) a combination thereof, and defining a longitudinal taper as they extend toward the distal end of the shaft.   
   
   
       16 . The intramedullary implant of  claim 13 , wherein at least a portion of the secondary flutes are disposed in between at least a portion of the primary flutes. 
   
   
       17 . The intramedullary implant of  claim 16 , wherein the secondary flutes have a smaller height than the primary flutes. 
   
   
       18 - 25 . (canceled) 
   
   
       26 . An intramedullary implant, comprising
 (a) a stem shaft with a first profile section, a transitional region, and a second profile section, wherein the transition region separates the first profile section and the second profile section; and   (b) a modular body, sleeve, neck, or any combination thereof.   
   
   
       27 . The intramedullary implant of  claim 26 , wherein the transitional region is tapered, parabolic, or stepped. 
   
   
       28 . The intramedullary implant of  claim 26 , wherein the second profile section comprises a downsized cylindrical section. 
   
   
       29 . The intramedullary implant of  claim 26 , wherein the transitional region and the second profile section are both tapered. 
   
   
       30 . The intramedullary implant of  claim 26 , wherein the stem provides stable three-point fixation inside the intramedullary canal. 
   
   
       31 . The intramedullary implant of  claim 26 , wherein the stem further comprises flutes. 
   
   
       32 . The intramedullary implant of  claim 26 , wherein the flutes comprise primary flutes and secondary flutes. 
   
   
       33 . A method of implanting an intramedullary stem into a patient's femur, comprising;
 (a) preparing the patient's femoral canal to receive a stem;   (b) providing a stem having a proximal end, a distal end, and a longitudinal length; primary and secondary flutes disposed along the longitudinal length, wherein the primary flutes extend the substantial length of the stem, and wherein the secondary flutes taper longitudinally toward the distal end of the stem; and   (c) implanting the stem into the patient's canal.   
   
   
       34 . The method of  claim 33 , wherein the surgeon uses a bone graft to rebuild bone before implanting the stem.