title: The effect of feedback from post-operative 3D CT on placement of femoral tunnels in single-bundle anatomic ACL reconstruction.
abstract: OBJECTIVE
  To evaluate the effect of feedback from post-operative 3D CT in the learning process of placing the femoral graft tunnel anatomically using the anteromedial (AM)-portal technique in single-bundle anterior cruciate ligament (ACL) reconstruction.
  
  
  METHODS
  An experienced knee surgeon converting from transtibial to AM-portal technique was offered post-operative feedback on tunnel placement. Three groups of patients were included: transtibial drilling, (AM1) anteromedial drilling without feedback and (AM2) anteromedial drilling with post-operative CT feedback. Intra-articular landmarks were used as the only guidance for tunnel placement. Tunnel position was compared to an ideal anatomical ACL position using the Bernard and Hertel grid and visual feedback was given on tunnel placements. The effect of feedback was measured as the distance from the anatomical centre, and spread of tunnel placements on post-operative CT performed feedback was initiated.
  
  
  RESULTS
  When comparing the femoral tunnel placement to an ideal anatomical centre, there was an improvement in the mean tunnel position after (A) changing from a transtibial to an anatomical technique and a further improvement after (B) initializing the radiological feedback. There was a great variation of femoral tunnel localizations when initially only using intra-articular landmarks as guidance for tunnel placement--this variation, however, converged towards the anatomical centre throughout the feedback period and the AM2 group had a femoral tunnel closer (P = 0.001) to the anatomical centre than the AM1 group.
  
  
  CONCLUSIONS
  Post-operative 3D CT is effective in the learning process of placing femoral tunnels anatomically by giving post-operative feedback on tunnel placement. Bony landmarks and ACL remnants were found unreliable as the only guidance for femoral tunnel placement in the AM-portal technique-therefore, the use of an aid is recommended to reduce unwanted tunnel variations in a learning phase.
  
  
  METHODS
  Cohort Study, Level III.
authors.affiliation: Surgical Department, Haraldsplass Deaconess Hospital, Pb 6165, Bergen, Norway. eivind.inderhaug@gmail.com.|Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Mons, Norway. eivind.inderhaug@gmail.com.
authors.forename: Eivind
authors.initials: E
authors.lastname: Inderhaug
authors.affiliation: Teres Bergen, Nesttun, Norway.
authors.forename: Allan
authors.initials: A
authors.lastname: Larsen
authors.affiliation: Surgical Department, Haraldsplass Deaconess Hospital, Pb 6165, Bergen, Norway.
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Strand
authors.affiliation: Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Mons, Norway.
authors.forename: Per Arne
authors.initials: PA
authors.lastname: Waaler
authors.affiliation: Surgical Department, Haraldsplass Deaconess Hospital, Pb 6165, Bergen, Norway.|Teres Bergen, Nesttun, Norway.|Department of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Mons, Norway.
authors.forename: Eirik
authors.initials: E
authors.lastname: Solheim
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction / Q000193:education* / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery; D007858:Learning; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: 3D CT; ACL; Anterior cruciate ligament reconstruction; Anteromedial portal