title: Native anterior cruciate ligament obliquity versus anterior cruciate ligament graft obliquity: an observational study using navigated measurements.
abstract: BACKGROUND
  The goal of anterior cruciate ligament reconstruction is to attain a graft that closely resembles the native anterior cruciate ligament anatomy. By reconstructing the original anatomy, one hopes to eliminate issues related to graft elongation, impingement, and excessive tension while achieving ideal knee kinematics.
  
  
  OBJECTIVE
  Clinical grafts placed using the transtibial technique will differ in the sagittal and coronal planes when compared with obliquity of the anatomic anterior cruciate ligament.
  
  
  METHODS
  Controlled laboratory study/case series; Level of evidence, 4.
  
  
  METHODS
  With the assistance of computer navigation, our study compared the anterior cruciate ligament orientation of 5 cadaver knees with 12 clinical anterior cruciate ligament-reconstructed knees using the transtibial technique.
  
  
  RESULTS
  Clinical graft obliquity differed from the anatomic anterior cruciate ligament in all flexion angles: 0 degrees, 30 degrees, 60 degrees, and 90 degrees. In the sagittal plane, the clinical graft obliquity differed from the anatomic anterior cruciate ligament by 13.6 degrees, 12.7 degrees, 16.7 degrees, and 17 degrees, respectively. In the coronal plane, the clinical graft obliquity differed from the anatomic anterior cruciate ligament by 4.9 degrees, 7.6 degrees, 8.9 degrees, and 12.7 degrees, respectively. Paired t tests demonstrated that the difference between the clinical and anatomic anterior cruciate ligament was significant (P <.05), except in the coronal plane at 0 degrees of flexion. In spite of this, all patients demonstrated a negative pivot shift and Lachman at the conclusion of their reconstructions and at 6-month follow-up.
  
  
  CONCLUSIONS
  The sagittal and coronal plane obliquity of well-functioning grafts placed using the transtibial technique were more vertical than anatomic fibers.
  
  
  CONCLUSIONS
  Graft obliquity, in both the coronal and sagittal plane, may be an important means to target appropriate anterior cruciate ligament graft position and can be monitored using surgical navigation systems.
authors.affiliation: Shoulder and Sports Medicine Service, Hospital for Special Surgery, New York, New York, USA. fcodystanford@gmail.com
authors.forename: Fatima C
authors.initials: FC
authors.lastname: Stanford
authors.forename: Daniel
authors.initials: D
authors.lastname: Kendoff
authors.forename: Russell F
authors.initials: RF
authors.lastname: Warren
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Pearle
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D006801:Humans; D007593:Joint Instability; D007719:Knee Joint / Q000033:anatomy & histology; D019370:Observation; D019637:Orthopedic Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted; D019737:Transplants