title: Arthroscopy Up to Date: Anterior Cruciate Ligament Anatomy.
abstract: OBJECTIVE
  To categorize and summarize up-to-date anterior cruciate ligament (ACL) research published in Arthroscopy and The American Journal of Sports Medicine and systematically review each subcategory, beginning with ACL anatomy.
  
  
  METHODS
  After searching for "anterior cruciate ligament" OR "ACL" in Arthroscopy and The American Journal of Sports Medicine from January 2012 through December 2014, we excluded articles more pertinent to ACL augmentation; open growth plates; and meniscal, chondral, or multiligamentous pathology. Studies were subcategorized for data extraction.
  
  
  RESULTS
  We included 212 studies that were classified into 8 categories: anatomy; basic science and biomechanics; tunnel position; graft selection; graft fixation; injury risk and rehabilitation; practice patterns and outcomes; and complications. Anatomic risk factors for ACL injury and post-reconstruction graft failure include a narrow intercondylar notch, low native ACL volume, and increased posterior slope. Regarding anatomic footprints, the femoral attachment is 43% of the proximal-to-distal lateral femoral condylar length whereas the posterior border of the tendon is 2.5 mm from the articular margin. The tibial attachment of the ACL is two-fifths of the medial-to-lateral interspinous distance and 15 mm anterior to the posterior cruciate ligament. Anatomic research using radiology and computed tomography to evaluate ACL graft placement shows poor interobserver and intraobserver reliability.
  
  
  CONCLUSIONS
  With a mind to improving outcomes, surgeons should be aware of anatomic risk factors (stenotic femoral notch, low ligament volume, and increased posterior slope) for ACL graft failure, have a precise understanding of arthroscopic landmarks identifying femoral and tibial footprint locations, and understand that imaging to evaluate graft placement is unreliable.
  
  
  METHODS
  Level III, systematic review of Level III evidence.
authors.affiliation: Pintler Surgical Specialists, Community Hospital of Anaconda, Anaconda, Montana, U.S.A.. Electronic address: carl.schillhammer@gmail.com.
authors.forename: Carl K
authors.initials: CK
authors.lastname: Schillhammer
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: John B
authors.initials: JB
authors.lastname: Reid
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: Jamie
authors.initials: J
authors.lastname: Rister
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: Sunil S
authors.initials: SS
authors.lastname: Jani
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Marvil
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: Austin W
authors.initials: AW
authors.lastname: Chen
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: Chris G
authors.initials: CG
authors.lastname: Anderson
authors.affiliation: Wake Forest University, Winston-Salem, North Carolina, U.S.A.
authors.forename: Sophia
authors.initials: S
authors.lastname: D'Agostino
authors.affiliation: Taos Orthopaedic Institute, Taos, New Mexico, U.S.A.
authors.forename: James H
authors.initials: JH
authors.lastname: Lubowitz
mesh_terms: D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001182:Arthroscopy; D005269:Femur / Q000033:anatomy & histology / Q000601:surgery; D006801:Humans; D007718:Knee Injuries / Q000601:surgery*; D007719:Knee Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D016119:Posterior Cruciate Ligament / Q000601:surgery; D015203:Reproducibility of Results; D012307:Risk Factors; D013710:Tendons / Q000637:transplantation*; D013977:Tibia / Q000033:anatomy & histology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D019737:Transplants