title: Optional entry point for retrograde femoral nailing: an anatomical study using the reverse engineering method.
abstract: OBJECTIVE
  To investigate the optimal entry point for retrograde femoral nailing using medical imaging and reverse engineering technologies.
  
  
  METHODS
  One hundred and eight adult cadaveric femurs were scanned using a computed tomography (CT) scanner. To obtain three-dimensional models, medical imaging and reverse engineering technologies were used. The insertion assessment was performed using computer aided design (CAD) software. The curve representing the mid-line in the intramedullary canal in the mid-shaft region was approximated using regression analysis. The curve was extended tangentially toward the femoral condyle, where the intersection between the curve and the condylar surface is the insertion site. The location of the insertion site was determined using the center of the anterior most of the intercodylar notch as a reference point. The measured distances were presented in medial-lateral and anterior-posterior perspectives from the reference point.
  
  
  RESULTS
  Average insertion site for Thai population was 0.56 mm lateral to and 12.67 mm medial to the anterior most of the intercondylar notch. The distance measured from intercondylar notch to the insertion site in the anterior-posterior direction was not significantly different between males and females; however a significant difference in the insertion site was found in medial-lateral directions.
  
  
  CONCLUSIONS
  The insertion site can be clinically approximated lying on the anterior-posterior axis, since the distance from the anterior-posterior axis to the insertion site is relatively small. The insertion site for the Thai population was found to be 12 mm anterior to the center of the anterior most of the intercondylar notch.
authors.forename: Nattapon
authors.initials: N
authors.lastname: Chantarapanich
authors.forename: Banchong
authors.initials: B
authors.lastname: Mahaisavariya
authors.forename: Kriskrai
authors.initials: K
authors.lastname: Sitthiseripratip
authors.forename: Pongwit
authors.initials: P
authors.lastname: Siribodhi
mesh_terms: D000328:Adult; D002102:Cadaver; D003198:Computer Simulation; D017076:Computer-Aided Design; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D036542:Tomography, Spiral Computed