title: Anatomically contoured plates for fixation of rib fractures.
abstract: BACKGROUND
  : Intraoperative contouring of long bridging plates for stabilization of flail chest injuries is difficult and time consuming. This study implemented for the first time biometric parameters to derive anatomically contoured rib plates. These plates were tested on a range of cadaveric ribs to quantify plate fit and to extract a best-fit plating configuration.
  
  
  METHODS
  : Three left and three right rib plates were designed, which accounted for anatomic parameters required when conforming a plate to the rib surface. The length lP over which each plate could trace the rib surface was evaluated on 109 cadaveric ribs. For each rib level 3-9, the plate design with the highest lP value was extracted to determine a best-fit plating configuration. Furthermore, the characteristic twist of rib surfaces was measured on 49 ribs to determine the surface congruency of anatomic plates with a constant twist.
  
  
  RESULTS
  : The tracing length lP of the best-fit plating configuration ranged from 12.5 cm to 14.7 cm for ribs 3-9. The corresponding range for standard plates was 7.1-13.7 cm. The average twist of ribs over 8-cm, 12-cm, and 16-cm segments was 8.3 degrees, 20.6 degrees, and 32.7 degrees, respectively. The constant twist of anatomic rib plates was not significantly different from the average rib twist.
  
  
  CONCLUSIONS
  : A small set of anatomic rib plates can minimize the need for intraoperative plate contouring for fixation of ribs 3-9. Anatomic rib plates can therefore reduce the time and complexity of flail chest stabilization and facilitate spanning of flail segments with long plates.
authors.affiliation: Legacy Biomechanics Laboratory, Portland, Oregon, USA. mbottlan@lhs.org
authors.forename: Michael
authors.initials: M
authors.lastname: Bottlang
authors.forename: Inga
authors.initials: I
authors.lastname: Helzel
authors.forename: William B
authors.initials: WB
authors.lastname: Long
authors.forename: Steven
authors.initials: S
authors.lastname: Madey
mesh_terms: D000368:Aged; D001699:Biometry; D001860:Bone Plates; D002102:Cadaver; D005260:Female; D005409:Flail Chest / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D016059:Range of Motion, Articular; D012253:Rib Fractures / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*