title: Three-dimensional computed tomography-based modeling of sagittal cadaveric femoral bowing and implications for intramedullary nailing.
abstract: OBJECTIVE
  To establish the nature and extent of femur sagittal bowing by determining outer and inner anterior cortex geometries and sizes using analytical 3-dimensional computed tomography modeling and relate the resultant femoral curvature with the curvatures of available intramedullary nails.
  
  
  METHODS
  Computed tomography scans were rendered in 3D using modeling software to reconstruct 2 geometries: (1) outer cortex and (2) medullary canal. Femoral bow in the sagittal plane and the anterior cortical thickness were measured. Three curvature points were selected on both the geometries. Exterior anterior cortex radius of curvature (AROC) and medullary canal radius of curvature (MROC) were compared within and between each femur pair.
  
  
  RESULTS
  Three groups of femurs exhibiting significantly different geometry patterns emerged: (1) AROC significantly greater than MROC, (2) AROC equivalent to MROC, and (3) AROC significantly smaller than MROC. Anterior cortical thickness ranged from 2.2 to 7.0 mm was significantly different for males versus females, and it varied inversely with age.
  
  
  CONCLUSIONS
  The study confirms that the radius of curvature of most intramedullary nails exceeds the sagittal radius of curvature of most adult femurs (both AROC and MROC). An intramedullary nail selected based on the anterior curvature would impinge on the anterior cortices at the proximal and distal anterior aspects of the femur in specimens with AROC > MROC. Conversely, in specimens with AROC < MROC, an intramedullary nail selected based on the anterior curvature would impinge on the proximal and distal posterior cortices. That cortical thickness varied significantly in accordance with gender and age is also relevant to surgical planning. MROC, in addition to the AROC alone, should be one of several design parameters used to match specific intramedullary nail design to an individual patient.
authors.affiliation: *Department of Orthopaedic Surgery and Rehabilitation, University of Texas Medical Branch, Galveston, TX; and †Orthopaedic Trauma Service, University of Texas, Houston, TX.
authors.forename: William L
authors.initials: WL
authors.lastname: Buford
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Turnbow
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Gugala
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Lindsey
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails; D002102:Cadaver; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D005594:Fracture Fixation, Intramedullary; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D014057:Tomography, X-Ray Computed