title: Modified transtibial versus anteromedial portal technique in anatomic single-bundle anterior cruciate ligament reconstruction: comparison of femoral tunnel position and clinical results.
abstract: BACKGROUND
  Although several studies have compared a conventional transtibial technique with an anteromedial (AM) portal technique for single-bundle (SB) anterior cruciate ligament (ACL) reconstruction, no study to date has investigated whether the modified transtibial technique results in the femoral tunnel being in a similar anatomic position and produces similar clinical outcomes with those of the AM portal technique.
  
  
  OBJECTIVE
  To compare the clinical outcomes and femoral tunnel position of SB ACL reconstruction using a modified transtibial technique (creating a femoral tunnel with varus and internal rotation of the tibia as well as modification of the tibial tunnel orientation) with those of SB ACL reconstruction using an AM portal technique.
  
  
  METHODS
  Randomized controlled trial; Level of evidence, 1.
  
  
  METHODS
  A total of 40 patients (40 knees) who underwent arthroscopic SB ACL reconstruction were included in this study. Patients were randomized using a computer-generated sequence into 2 groups: 20 patients by the modified transtibial technique (group 1) and 20 patients by the AM portal technique (group 2). Clinical evaluations included the 2000 International Knee Documentation Committee (IKDC) subjective knee score, Lysholm knee score, Tegner activity scale, Lachman test, pivot-shift test, 2000 IKDC knee examination, and KT-1000 arthrometer measurement. Three-dimensional computed tomography scans were analyzed according to the quadrant method, and the obliquity of the femoral tunnels in the coronal and sagittal planes and the size of the tunnel orifice were measured.
  
  
  RESULTS
  All clinical parameters improved significantly after SB ACL reconstruction, with no between-group differences. The mean distance of the femoral tunnel center location from the posterior condylar surface (0.8% difference; P = .167) and from the Blumensaat line (2.1% difference; P = .067) was similar in groups 1 and 2. The mean coronal obliquity of the femoral tunnel was significantly lower in group 1 than in group 2 (42.5° ± 6.1° vs 49.3° ± 7.2°, respectively; P = .001), but the mean sagittal obliquity was similar between the 2 groups (41.9° ± 6.1° vs 43.3° ± 5.4°, respectively; P = .303). The mean area of the tunnel orifice was significantly greater in group 1 than in group 2 (11.6 ± 1.4 × 9.2 ± 1.6 mm vs 10.3 ± 1.1 × 9.1 ± 1.4 mm, respectively; P = .013).
  
  
  CONCLUSIONS
  The modified transtibial technique for SB ACL reconstruction showed good clinical results and anatomic placement of the femoral tunnel, similar with those of the AM portal technique.
authors.affiliation: Department of Orthopedic Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Yoon-Seok
authors.initials: YS
authors.lastname: Youm
authors.affiliation: Department of Orthopedic Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea sdcho@uuh.ulsan.kr.
authors.forename: Sung-Do
authors.initials: SD
authors.lastname: Cho
authors.affiliation: Department of Orthopedic Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Seon-Ho
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Orthopedic Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Chang-Hyun
authors.initials: CH
authors.lastname: Youn
mesh_terms: D000125:Achilles Tendon / Q000637:transplantation; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D063868:Patient Outcome Assessment; D011446:Prospective Studies; D013977:Tibia / Q000000981:diagnostic imaging* / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: ACL reconstruction; CT analysis; anatomic single bundle; clinical results