title: The effect of femoral tunnel position on graft forces during inlay posterior cruciate ligament reconstruction.
abstract: BACKGROUND
  The femoral tunnel may be positioned centrally or eccentrically within the posterior cruciate ligament footprint during a single-bundle posterior cruciate ligament reconstruction.
  
  
  OBJECTIVE
  After reconstruction, graft forces are significantly different from those of the native posterior cruciate ligament and are affected by the position of the femoral tunnel.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  The resultant force in the native posterior cruciate ligament was measured in nine cadaveric knees as the knee was flexed from -5 degrees to 120 degrees of flexion. Posterior cruciate ligament reconstruction was performed with the femoral side of the graft positioned centrally and then offset 5 mm eccentric to the central position.
  
  
  RESULTS
  Mean graft forces were not significantly different between eccentric and central tunnel positions during passive knee extension between 120 degrees and 0 degrees of flexion; at 5 degrees of hyperextension, the eccentric position generated significantly lower graft forces. For both reconstruction techniques, mean graft forces were significantly higher than those for the native posterior cruciate ligament beyond approximately 90 degrees of flexion, for 5 N.m internal and external tibial torque; 5 N.m varus and valgus moment.
  
  
  CONCLUSIONS
  Graft force reductions achieved with the eccentric femoral position appear to be relatively small compared with the forces expected during rehabilitation and activities of daily living.
  
  
  CONCLUSIONS
  After posterior cruciate ligament graft reconstruction, rehabilitation activities that load the knee at high degrees of flexion should be avoided to limit excessive forces on the maturing graft.
authors.affiliation: Department of Orthopaedic Surgery, University of California at Los Angeles, Los Angeles, California 90095-6902, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Oakes
authors.forename: Keith L
authors.initials: KL
authors.lastname: Markolf
authors.forename: Justin
authors.initials: J
authors.lastname: McWilliams
authors.forename: Charles R
authors.initials: CR
authors.lastname: Young
authors.forename: David R
authors.initials: DR
authors.lastname: McAllister
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007718:Knee Injuries / Q000473:pathology / Q000534:rehabilitation* / Q000601:surgery*; D007719:Knee Joint / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D016119:Posterior Cruciate Ligament / Q000293:injuries* / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D013710:Tendons / Q000637:transplantation*; D016474:Weight-Bearing