title: Influence of the different anteromedial portal on femoral tunnel orientation during anatomic ACL reconstruction.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of femoral tunnel orientation, drilled through the accessory anteromedial (AAM) portal or the high AM portal in anatomic anterior cruciate ligament (ACL) reconstruction.
  
  
  METHODS
  In 16 cadaver knees, using o'clock method, centers of the ACL femoral footprint were drilled with an 8-mm reamer via an AAM portal (eight knees) or a high AM portal (eight knees). Computed tomography (CT) scans were taken of each knee. Three-dimensional (3D) models were constructed to identify the femoral tunnel orientation and to create femoral tunnel virtual cylinders for measuring tunnel angles and length.
  
  
  RESULTS
  In two of the 16 specimens, we observed a posterior femoral cortex blowout (PFCB) when drilling through a high AM portal. When drilled through the high AM portal, the femoral tunnel length was significantly shorter than when using an AAM portal (30.3 ± 3.8 mm and 38.2 ± 3.1 mm, p < 0.001). The femoral tunnel length was significantly shorter in the group with PFCB compared to the group with no PFCB (25.9 ± 0.6 mm and 35.5 ± 4.5 mm, p = 0.011). The axial obliquity of the high AM portal was significantly higher than that of the AAM portal (52.2 ± 5.9° and 43.0 ± 2.3°, p = 0.003).
  
  
  CONCLUSIONS
  In anatomic ACL reconstruction, a mal-positioned AM portal can cause abnormal tunnel orientation, which may lead to mechanical failure during ACL reconstruction. Therefore, it is important to select accurate AM portal positioning, and possibly using an AAM portal by measuring an accurate position when drilling a femoral tunnel in anatomic ACL reconstruction.
authors.affiliation: Korean Armed Forces Capital Hospital, Republic of Korea.
authors.forename: Dong-Kyu
authors.initials: DK
authors.lastname: Moon
authors.affiliation: Department of Orthopaedic Surgery, Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju, Republic of Korea.
authors.forename: Ho-Seung
authors.initials: HS
authors.lastname: Jo
authors.affiliation: Orthopaedic Surgery, Gyeongsang National University Hospital, Republic of Korea.
authors.forename: Dong-Yeong
authors.initials: DY
authors.lastname: Lee
authors.affiliation: Orthopaedic Surgery, Gyeongsang National University Hospital, Republic of Korea.
authors.forename: Dong-Geun
authors.initials: DG
authors.lastname: Kang
authors.affiliation: Orthopaedic Surgery, Gyeongsang National University Hospital, Republic of Korea.
authors.forename: June-Ho
authors.initials: JH
authors.lastname: Byun
authors.affiliation: Gyeongsang National University Graduate School of Medicine Jinju, Republic of Korea. Electronic address: hscspine@hanmail.net.
authors.forename: Sun-Chul
authors.initials: SC
authors.lastname: Hwang
mesh_terms: D000368:Aged; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000175:diagnosis / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002102:Cadaver; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D013525:Surgical Instruments; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Anterior cruciate ligament; Anteromedial; Orientation; Portal; Reconstruction