title: Interference screw fixation of doubled flexor tendon graft in anterior cruciate ligament reconstruction - biomechanical evaluation with cyclic elongation.
abstract: OBJECTIVE
  To biomechanically evaluate interference screw fixation of the doubled flexor tendon graft in anterior cruciate ligament reconstruction using cyclic elongation.
  
  
  METHODS
  Biomechanical properties of the interference screw fixation of the flexor tendons were compared with those of three standard fixation techniques which had been commonly performed in anterior cruciate ligament reconstruction.
  
  
  BACKGROUND
  The interference screw fixation of the flexor tendon graft has attracted notice because of various possible advantages.
  
  
  METHODS
  Forty fresh frozen porcine hind limbs were divided into four groups of ten knees each. Anterior cruciate ligament reconstruction was carried out in each group using one of four different procedures. For each group, five femur-graft-tibia complexes underwent submaximal cyclic elongation of 5000 cycles after initial tension of 80 N was applied. Then, tensile testing was performed in the same manner for the complex with a tensile tester. The remaining five complexes were examined in the same tensile test without applying any cyclic elongation.
  
  
  RESULTS
  The initial tension was more rapidly relaxed by cyclic elongation in the flexor tendon graft fixed with interference screws than in the bone-patellar tendon-bone graft fixed with two standard techniques. After cyclic elongation, while the ultimate failure load of the former was significantly lower than the latter, the linear stiffness of the former was significantly higher than the flexor tendon graft fixed with sutures.
  
  
  CONCLUSIONS
  The present study has clarified that the advantage of the interference fixation for the doubled flexor tendon graft is the high linear stiffness of the FGT complex, and the disadvantage of this screw is the low ultimate failure load of the FGT complex.
  
  
  CONCLUSIONS
  The present study has suggested that vigorous activities should not be permitted for the patients in the early period after anterior cruciate ligament reconstruction using this fixation technique, because of its low ultimate failure load.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Hokkaido University, Kitu-ku-Kita-15 Nishi 7, Sapporo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakano
authors.forename: K
authors.initials: K
authors.lastname: Yasuda
authors.forename: H
authors.initials: H
authors.lastname: Tohyama
authors.forename: M
authors.initials: M
authors.lastname: Yamanaka
authors.forename: T
authors.initials: T
authors.lastname: Wada
authors.forename: K
authors.initials: K
authors.lastname: Kaneda
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D004195:Disease Models, Animal; D004548:Elasticity; D005269:Femur / Q000601:surgery; D006614:Hindlimb; D017847:Patellar Ligament / Q000502:physiology / Q000637:transplantation; D013314:Stress, Mechanical; D013536:Suture Techniques; D013552:Swine; D013710:Tendons / Q000502:physiology / Q000637:transplantation*; D013718:Tensile Strength; D013977:Tibia / Q000601:surgery; D016474:Weight-Bearing / Q000502:physiology