title: Tension wire position for hybrid external fixation of the proximal tibia.
abstract: OBJECTIVE
  To compare a new configuration of proximal wires for hybrid external fixation with the standard configuration.
  
  
  METHODS
  Biomechanical testing of five matched pairs of fresh cadaveric tibia.
  
  
  METHODS
  The authors compared the standard tension wire configuration of the three proximal wires with a more sagittal orientation of the oblique wires. A second study compared the new configuration with two wires and an offset half-pin. A two-centimeter segmental defect was created just distal to the tibial tubercle and the tibias fixed in a Montecelli Spinelli (Howmedica, NJ, U.S.A.) hybrid frame. The constructs were biomechanically tested using an Instron servohydraulic biaxial testing machine.
  
  
  RESULTS
  There was a significant 67 percent decrease in displacement during anterior posterior bending and a significant 40 percent decrease in displacement in posterior bending with the new configuration compared with the standard configuration (p < 0.05). The differences in stability in all other testing modes were not significant. There was no significant difference between the new configuration and the two wire and off-set half-pin configuration.
  
  
  CONCLUSIONS
  We recommend anterior placement of the oblique tension wires in the proximal tibia to more effectively resist bending in the sagittal plane, which is the most common deforming force on proximal metaphyseal fractures.
authors.affiliation: University Hospital, Brooklyn, New York, USA.
authors.forename: J
authors.initials: J
authors.lastname: Geller
authors.forename: P
authors.initials: P
authors.lastname: Tornetta
authors.forename: D
authors.initials: D
authors.lastname: Tiburzi
authors.forename: F
authors.initials: F
authors.lastname: Kummer
authors.forename: K
authors.initials: K
authors.lastname: Koval
mesh_terms: D001696:Biomechanical Phenomena; D002102:Cadaver; D016267:External Fixators; D005592:Fracture Fixation / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D013978:Tibial Fractures / Q000601:surgery*