title: Femoral fixation strength following soft-tissue posterolateral corner reconstruction using fibular-based technique: Biomechanical analysis of four techniques in normal and low-density synthetic bone.
abstract: BACKGROUND
  Optimal femoral fixation of soft-tissue grafts has been described for anterior cruciate ligament reconstruction. Posterolateral corner reconstruction differs from ACL reconstruction in two ways: (a) soft-tissue fixation into the femur requires two tails and (b) the line of force is different. Our purpose was to determine the optimal femoral fixation of soft-tissue grafts during posterolateral corner reconstructions. We hypothesized that interference screw fixation is the strongest technique in normal-density lateral femoral condyle, whereas, cortically-based fixation techniques are stronger methods in low-density lateral femoral condyle.
  
  
  METHODS
  We evaluated elongation during cyclic loading, yield load, peak load-to-failure, and stiffness of four soft-tissue graft femoral fixation methods during posterolateral corner reconstruction. Our model included bovine flexor tendons and contoured synthetic bones. Grafts were secured to the lateral epicondyle in normal- or low-density bone models using spiked washer, button, interference screw, or button and interference screw. Five specimens for each were tested in each bone density. Analysis of variance using Tukey-Kramer adjustment for multiple hypothesis testing was used. Six cadaver bones whose density was analyzed using computerized tomography scan quantitation were tested using interference screw fixation.
  
  
  RESULTS
  No method produced significantly stronger yield load or peak load-to-failure in normal-density bone. In low-density bone, cortically-based methods produced significantly higher yield load or peak load-to-failure. Yield load or peak load-to-failure was significantly higher in normal-density bone when using spiked washer or interference screw fixation.
  
  
  CONCLUSIONS
  No femoral fixation method tested produced superior yield load or peak load-to-failure. Spiked washer and interference screw fixation are inferior fixation methods in low-density bone.
  
  
  CONCLUSIONS
  For fibular-based posterolateral corner reconstructions, all fixation methods tested are acceptable in high-density bone, while cortical fixation methods should be considered in low-density bone.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Penn State Hershey College of Medicine, Penn State Hershey Bone and Joint Institute, Hershey, PA, United States. Electronic address: rgallo@hmc.psu.edu.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Gallo
authors.affiliation: Steel Valley Orthopedic Associates, P.C., Jefferson Hills, PA, United States.
authors.forename: Vikram
authors.initials: V
authors.lastname: Sathyendra
authors.affiliation: College of Health and Human Development, Pennsylvania State University, University Park, PA, United States.
authors.forename: Neil A
authors.initials: NA
authors.lastname: Sharkey
authors.affiliation: Department of Orthopaedics and Rehabilitation, Penn State Hershey College of Medicine, Penn State Hershey Bone and Joint Institute, Hershey, PA, United States.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Lewis
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D002417:Cattle; D004195:Disease Models, Animal; D005360:Fibula / Q000601:surgery*; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D008422:Materials Testing; D019736:Prostheses and Implants; D016059:Range of Motion, Articular; D016474:Weight-Bearing
keywords: Femoral graft fixation; Lateral collateral ligament; Posterolateral corner reconstruction