title: In vitro and in vivo AM and PL tunnel positioning in anatomical double bundle anterior cruciate ligament reconstruction.
abstract: BACKGROUND
  There have been few studies investigating the correct anatomical femoral and tibial tunnel placement in double bundle anterior cruciate ligament (ACL) reconstruction.
  
  
  OBJECTIVE
  To compare anteromedial (AM) and posterolateral (PL) tunnel positions in anatomical double bundle ACL reconstruction in human cadaver and patient knees.
  
  
  METHODS
  Fifteen fresh-frozen non-paired adult human knees and 27 patients (27 knees) were evaluated. In the cadaver knees, AM and PL bundles were identified by their difference in tension patterns. Their femoral centers were marked with a K-wire, and cut from the femoral insertion site. After this, each bundle was divided at the tibial side. The center of each bundle insertion was again marked with a K-wire, and 5-7-mm tunnels were drilled with transportal or outside-in technique. In patient knees, each tunnel was made according to the native ACL foot print and bony landmarks using transtibial technique (n = 5) and transportal technique (n = 22). Tunnel placement was evaluated using a C-arm X-ray device and 3D CT. For the femoral side assessment, Bernard and Hertel's technique was used. For the tibial side assessment, Amis and Jakob's technique was used.
  
  
  RESULTS
  The femoral AM tunnel in the cadaver knees was placed in a significantly deeper position when compared to patient knees. There was no significant difference in the AM vertical placement or in the PL tunnel placement in the femur. No significant differences were observed in the tibial tunnel placements between cadaver and patient knees.
  
  
  CONCLUSIONS
  In vivo positioning of the femoral AM bundle differed significantly from the in vitro positioning.
authors: Division of Rehabilitation Medicine, Gunma University Hospital, Showa-machi 3-39-15, Gunma, Maebashi, Japan. sekaiwoseisu@yahoo.co.jp
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