title: Tunnel positions in transportal versus transtibial anterior cruciate ligament reconstruction: a case-control magnetic resonance imaging study.
abstract: OBJECTIVE
  The purpose of this study was to examine the difference in the position of bone tunnels prepared by the transportal technique versus the transtibial technique in anterior cruciate ligament (ACL) reconstruction.
  
  
  METHODS
  A consecutive series of 42 patients receiving single-bundle ACL reconstructions were recruited between July 1, 2007, and December 31, 2008. The preparations of the femoral tunnel were performed by the transtibial technique in the first 21 cases and by the transportal technique in the subsequent 21 cases. Magnetic resonance imaging examination was performed in 39 patients (93%) 1 year after the index operation (20 transtibial and 19 transportal). Optimal tunnel position was defined as a lateralized femoral tunnel at a position of less than 11 o'clock for a right knee or more than 1 o'clock for a left knee, an adequate posteriorized femoral tunnel in the fourth quadrant of the modified Bernard line, and a tibial tunnel located in the second quadrant of the modified Amis line.
  
  
  RESULTS
  The average clock position was 10:18 in the transportal group and 10:54 in the transtibial group (P < .001). Five outliers were found in the transtibial group but none in the transportal group. Concerning the femoral tunnel position on the sagittal-cut magnetic resonance imaging scan, the average position along the modified Bernard line was 74% in the transportal group and 69% in the transtibial group (P = .029). Concerning the tibial tunnel position, the average tibial tunnel positions along the modified Amis line were 47% and 52%, respectively (P = .019).
  
  
  CONCLUSIONS
  The adoption of the transportal technique in single-bundle ACL reconstruction produced improved positions in both the femoral and tibial tunnels when compared with the transtibial technique.
  
  
  METHODS
  Level III, case-control study.
authors.affiliation: Division of Sports and Arthroscopic Surgery, Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. peterwpy@hkucc.hku.hk
authors.forename: W P
authors.initials: WP
authors.lastname: Yau
authors.forename: August W M
authors.initials: AW
authors.lastname: Fok
authors.forename: Dennis K H
authors.initials: DK
authors.lastname: Yee
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013977:Tibia / Q000601:surgery*; D055815:Young Adult