title: Mechanical properties of soft tissue femoral fixation devices for anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  To evaluate femoral soft tissue fixation for anterior cruciate ligament reconstruction.
  
  
  OBJECTIVE
  Femoral fixation devices have different ultimate strengths and slippage under cyclic loading.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Thirty-three porcine femora were used to study interference screw (9), Endobutton (8), Rigidfix cross-pin (8), and Bio-Transfix cross-pin (8) fixation methods. Fixation slippage was evaluated under cyclical load from 50 N to 250 N using a materials testing machine. Ultimate load was determined with a single load to failure.
  
  
  RESULTS
  Total graft slippage was greater (P <.001) for the Rigidfix (6.02 +/- 2.12 mm) and the interference screw (5.44 +/- 3.25 mm) compared to the Endobutton (1.75 +/- 0.97 mm) and the Bio-Transfix (1.14 +/- 0.53 mm). All techniques showed the greatest slippage during the first 100 cycles (Rigidfix 84%, Endobutton 70%, interference screw 56%, and Bio-Transfix 55%). The failure load for the interference screw technique (539 +/- 114 N) was lower (P =.0008) than for the other 3 techniques (737 +/- 140 N for Rigidfix, 746 +/- 119 N for Bio-Transfix, and 864 +/- 164 N for Endobutton).
  
  
  CONCLUSIONS
  The interference screw and the Rigidfix fixation demonstrated inferior fixation biomechanics compared to the Bio-Transfix and the Endobutton techniques.
authors.affiliation: Center for Shoulder, Elbow, and Sports Medicine, Department of Orthopaedic Surgery, Columbia University, New York, New York 10032, USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ahmad
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Gardner
authors.forename: Megan
authors.initials: M
authors.lastname: Groh
authors.forename: Johnny
authors.initials: J
authors.lastname: Arnouk
authors.forename: William N
authors.initials: WN
authors.lastname: Levine
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001863:Bone Screws; D005269:Femur / Q000601:surgery*; D009984:Orthopedic Fixation Devices; D019651:Plastic Surgery Procedures / Q000295:instrumentation* / Q000379:methods; D013552:Swine; D013710:Tendons / Q000637:transplantation*