title: Initial fixation strength of a new hybrid technique for femoral ACL graft fixation: the bone wedge technique.
abstract: BACKGROUND
  Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation.
  
  
  OBJECTIVE
  A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screw placed behind a bone wedge provides a higher fixation strength as aperture fixation with a screw alone matching the size of the tunnel.
  
  
  METHODS
  Experimental laboratory study.
  
  
  METHODS
  We evaluated the initial fixation strength (single cycle and cyclic loading tests) of hybrid and interference screw aperture fixation using different sized interference screws in porcine knees.
  
  
  RESULTS
  Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. The use of an undersized screw alone resulted in low fixation strength.
  
  
  CONCLUSIONS
  The initial fixation strength of the hybrid technique with undersized screws is comparable to that of interference screw fixation matching the size.
  
  
  CONCLUSIONS
  The new "bone wedge fixation" is an alternative for ACL graft fixation without the risk of graft laceration and graft rotation.
authors.affiliation: Department of Trauma-, Hand-, and Reconstructive Surgery, Westfälische Wilhelms-University Münster, Waldeyerstr, 1, 48149, Münster, Germany.
authors.forename: Mirco
authors.initials: M
authors.lastname: Herbort
authors.forename: Andre
authors.initials: A
authors.lastname: Weimann
authors.forename: Thore
authors.initials: T
authors.lastname: Zantop
authors.forename: Michael
authors.initials: M
authors.lastname: Strobel
authors.forename: Michael
authors.initials: M
authors.lastname: Raschke
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005269:Femur / Q000601:surgery*; D066298:In Vitro Techniques; D019637:Orthopedic Procedures / Q000379:methods*; D011897:Random Allocation; D018709:Statistics, Nonparametric; D013552:Swine; D013718:Tensile Strength / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology