title: Initial fixation strength of two bioabsorbable pins for the fixation of hamstring grafts compared to interference screw fixation: single cycle and cyclic loading.
abstract: BACKGROUND
  During the early postoperative period, the fixation of a hamstring graft to the bone tunnel is the primary factor in limiting rehabilitation.
  
  
  OBJECTIVE
  The initial fixation strength of a double cross pin fixation technique is comparable with the biodegradable interference screw fixation technique.
  
  
  METHODS
  Experimental laboratory study.
  
  
  METHODS
  The authors examined the initial fixation strength of two 3.3-mm bioabsorbable pins compared to interference screws for hamstring grafts in bovine knees.
  
  
  RESULTS
  Analysis of yield load, maximum load, and stiffness in the single-cycle loading test showed no statistically significant differences for cross pin and interference fixation (P <.05). For cross pins and interference screws, the mean displacement under 1000 cycles to 250 N was 5.07 ( +/- 1.9) mm and 4.81 ( +/- 2.5) mm, stiffness 252 ( +/- 78) N/mm and 289 ( +/- 148) N/mm. Only grafts fixed with cross pins survived 1000 cycles to 450 N.
  
  
  CONCLUSIONS
  The initial fixation strength of the double cross pin technique is comparable to that of interference screw fixation with a stiffness comparable to that of the native ACL.
  
  
  CONCLUSIONS
  Hamstring graft fixation using two cross pins provides an alternative to bioabsorbable interference screw fixation.
authors.affiliation: Department of Orthopaedic Surgery, Christian-Albrechts-University Kiel, Kiel, Germany.
authors.forename: Thore
authors.initials: T
authors.lastname: Zantop
authors.forename: Andre
authors.initials: A
authors.lastname: Weimann
authors.forename: Markus
authors.initials: M
authors.lastname: Rümmler
authors.forename: Joachim
authors.initials: J
authors.lastname: Hassenpflug
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D001858:Bone Nails; D001863:Bone Screws; D002102:Cadaver; D002417:Cattle; D006801:Humans; D008875:Middle Aged; D013710:Tendons / Q000637:transplantation*; D013718:Tensile Strength