title: Anatomic single-bundle ACL reconstruction is possible with use of the modified transtibial technique: a comparison with the anteromedial transportal technique.
abstract: BACKGROUND
  Anatomic anterior cruciate ligament (ACL) reconstruction is essential to the restoration of normal knee kinematics and to achieving successful results after ACL surgery. The purpose of this study was to evaluate whether anatomic single-bundle ACL reconstruction can be performed with use of the modified transtibial technique such that the tunnel characteristics are not substantially different from those of the anteromedial transportal technique, with comparable clinical results.
  
  
  METHODS
  One hundred and four patients underwent single-bundle ACL reconstruction performed with use of either the modified transtibial technique or the anteromedial transportal technique. Each group included fifty-two patients retrospectively matched on the basis of age, sex, and body mass index. All patients had postoperative computed tomography (CT) and a minimum duration of follow-up of twenty-four-months. CT parameters, including tunnel position, tunnel length and shape, and graft obliquity, were evaluated. Clinical assessments were based on manual laxity tests, arthrometric analysis, and clinical scores recorded preoperatively and at the time of follow-up.
  
  
  RESULTS
  The femoral tunnel was placed at a slightly inferior and anterior position with use of the modified transtibial technique compared with the anteromedial transportal technique, but the difference was not significant (superior-inferior mean [and standard deviation], 35.7% ± 3.1% versus 33.9% ± 4.1%, p > 0.05, and anterior-posterior mean, 31.6 ± 6.8% versus 35.1 ± 6.9%, p > 0.05, as assessed with use of the quadrant method). The femoral tunnel length was significantly longer (p < 0.05) and the tibial tunnel length was significantly shorter (p < 0.05) with use of the modified transtibial technique compared with the anteromedial transportal technique (mean femoral tunnel length, 40.5 ± 4.2 mm versus 34.4 ± 2.6 mm and mean tibial tunnel length, 32.3 ± 3.1 mm versus 35.5 ± 2.7 mm); however, tunnel length was sufficient to allow for adequate fixation. There were no significant differences between the two groups in terms of tibial tunnel position, graft obliquity, tibial tunnel widening, and clinical results.
  
  
  CONCLUSIONS
  Tunnel characteristics including anatomic position, graft obliquity, and tunnel widening after single-bundle ACL reconstruction performed with use of the modified transtibial technique were not significantly different from those of the anteromedial transportal technique, and clinical results were comparable.
authors.affiliation: Department of Orthopaedic Surgery, Hallym University Sacred Heart Hospital, Pyeongchon-dong, Dongan-gu, Anyang-si, Gyeonggi-do, 431-070, South Korea.
authors.forename: Joon Kyu
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Hospital, 101 Daehang-ro, Jongno-gu, Seoul, 110-744, South Korea. E-mail address for M.C. Lee: leemc@snu.ac.kr.
authors.forename: Sahnghoon
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Hospital, 101 Daehang-ro, Jongno-gu, Seoul, 110-744, South Korea. E-mail address for M.C. Lee: leemc@snu.ac.kr.
authors.forename: Sang Cheol
authors.initials: SC
authors.lastname: Seong
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Hospital, 101 Daehang-ro, Jongno-gu, Seoul, 110-744, South Korea. E-mail address for M.C. Lee: leemc@snu.ac.kr.
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult