title: The effect of cement mixing time on the biomechanics of cement augmented plated fractures in canine femora.
abstract: OBJECTIVE
  The goal of this study was to determine the effect of cement mixing time and, hence, cement viscosity on the biomechanical behavior of femoral fracture fixation.
  
  
  METHODS
  Cadaveric plated canine femoral fracture model, comparing treatments in matched pairs.
  
  
  METHODS
  Orthopaedic biomechanics laboratory.
  
  
  METHODS
  Cement was inserted both as a liquid and as a paste in standard and oversized screw holes to augment fixation with plates and screws.
  
  
  METHODS
  Standard 4-point bending tests were performed to obtain stiffness and failure load values.
  
  
  RESULTS
  Liquid cement had a 1.38 times increase in stiffness and a failure load 1.84 times greater compared with paste cement, regardless of hole size with a gap at the fracture site (P < 0.05). Liquid cement had a force to failure of 1.77 and 1.91 times in the standard-sized and oversized holes, respectively, when compared with paste cement (P < 0.05).
  
  
  CONCLUSIONS
  When the cement was inserted in a liquid state in a plated femoral diaphyseal fracture with a gap, screw purchase augmentation achieved greater bending stiffness and resisted a greater failure load.
authors.affiliation: Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Chris H
authors.initials: CH
authors.lastname: Gallimore
authors.forename: Alison J
authors.initials: AJ
authors.lastname: McConnell
authors.forename: Rad
authors.initials: R
authors.lastname: Zdero
authors.forename: Henry
authors.initials: H
authors.lastname: Koo
authors.forename: Michael D
authors.initials: MD
authors.lastname: McKee
authors.forename: Emil H
authors.initials: EH
authors.lastname: Schemitsch
mesh_terms: D000818:Animals; D001860:Bone Plates; D002484:Cementation / Q000379:methods*; D019245:Compressive Strength; D004285:Dogs; D055119:Elastic Modulus; D005264:Femoral Fractures / Q000503:physiopathology* / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006244:Hardness; D066298:In Vitro Techniques; D013314:Stress, Mechanical; D013718:Tensile Strength; D013997:Time Factors