title: Anteromedial versus transtibial tunnel drilling in anterior cruciate ligament reconstructions: a systematic review.
abstract: OBJECTIVE
  Failure to anatomically reconstruct the femoral footprint can lead to rotational instability and clinical failure. Thus we sought to compare femoral tunnel drilling techniques, specifically anteromedial (AM) and transtibial (TT) methods, with respect to rotational stability.
  
  
  METHODS
  In this study we evaluated available scientific support for the ability of both techniques to achieve rotational stability of the knee through a systematic review of the literature for directly comparative biomechanical and clinical studies.
  
  
  RESULTS
  We identified 9 studies (5 clinical Level II or III studies and 4 cadaveric studies) that directly compared AM and TT techniques. Three cadaveric and 2 clinical studies showed superior rotational stability with the AM technique as compared with the TT technique, whereas 2 cadaveric studies and 1 clinical study were unable to show any similar differences. Two studies showed superior clinical outcomes with the AM technique, whereas 3 studies were unable to show any difference.
  
  
  CONCLUSIONS
  In this systematic review of clinical and biomechanical studies directly comparing AM and TT techniques for anterior cruciate ligament reconstruction (ACLR) in the literature, there are mixed results, with some studies finding superior rotational stability and clinical outcomes with the AM technique and some finding no difference. No studies showed significantly better results with the TT technique. This study shows that the AM portal technique for ACLR may be more likely to produce improved clinical and biomechanical outcomes but that the TT technique is capable of producing similar outcomes.
  
  
  METHODS
  Level III, systematic review of Level II and III studies plus cadaver studies.
authors.affiliation: Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA. p.n.chalmers@gmail.com
authors.forename: Peter N
authors.initials: PN
authors.lastname: Chalmers
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Mall
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
authors.forename: Nikhil N
authors.initials: NN
authors.lastname: Verma
authors.forename: Charles A
authors.initials: CA
authors.lastname: Bush-Joseph
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D005269:Femur / Q000601:surgery*; D006801:Humans; D010027:Osteotomy / Q000379:methods; D016032:Randomized Controlled Trials as Topic; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D012399:Rotation; D016896:Treatment Outcome