title: Biomechanical comparison between the rectangular-tunnel and the round-tunnel anterior cruciate ligament reconstruction procedures with a bone-patellar tendon-bone graft.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effectiveness of 2 anterior cruciate ligament (ACL) reconstruction techniques using a bone-patellar tendon-bone (BPTB) graft with femoral tunnel, either a rectangular tunnel (RET) or a round tunnel (ROT).
  
  
  METHODS
  For experiment 1, nine fresh-frozen human cadaveric knees were tested with a robotic/universal force-moment sensor system to determine the initial optimal tension: the amount of graft tension at 15° of flexion most closely resembling the anterior laxity of a normal knee. The value was estimated by repeatedly measuring anterior laxity when 100 N of anteroposterior drawer load was applied to the knees at 30° of flexion after RET ACL or ROT ACL reconstruction. For experiment 2, six fresh-frozen human cadaveric knees were selected. On the basis of the initial tension determined in experiment 1, RET ACL reconstruction was conducted with the graft tensioned to 10 N, followed by ROT ACL reconstruction on the same knee at 40 N of initial tension, and the biomechanical efficacy of the 2 methods was compared.
  
  
  RESULTS
  For experiment 1, the mean laxity match tension at 15° of flexion was 8.6 ± 4.8 N and 34.8 ± 9.2 N for RET- and ROT-reconstructed knees, respectively. For experiment 2, both RET and ROT ACL reconstructions were successful in controlling anterior tibial translation under anterior tibial loads, with the graft initially tensioned to 10 N in the former and to 40 N in the latter. However, the greater tensioning in ROT reconstruction led to proximal, posterior, and lateral displacement of the tibia along with its external and valgus rotation.
  
  
  CONCLUSIONS
  The RET ACL-reconstructed knee more closely resembled the normal knee in biomechanical behavior. Although ROT reconstruction successfully controlled anterior translation with greater initial tensioning to the graft, the normal positional relation between the tibia and femur was impaired.
  
  
  CONCLUSIONS
  Rectangular femoral ACL fixation constructs and grafts may prove more efficacious at restoring in vivo ACL kinematics than round femoral tunnels.
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Sapporo Medical University, Sapporo, Japan. Electronic address: suzutomo@sapmed.ac.jp.
authors: Tomoyuki
authors: T
authors: Suzuki
authors: Sports Orthopaedic Center, Osaka Yukioka Hospital, Osaka, Japan.
authors: Konsei
authors: K
authors: Shino
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors: Hidenori
authors: H
authors: Otsubo
authors: Department of Musculoskeletal Biomechanics and Surgical Development, Sapporo Medical University, Sapporo, Japan.
authors: Daisuke
authors: D
authors: Suzuki
authors: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors: Tatsuo
authors: T
authors: Mae
authors: 2nd Department of Anatomy, Sapporo Medical University, Sapporo, Japan.
authors: Mineko
authors: M
authors: Fujimiya
authors: Department of Orthopaedic Surgery, Graduate School of Medicine, Sapporo Medical University, Sapporo, Japan.
authors: Toshihiko
authors: T
authors: Yamashita
authors: Biomechanics Laboratory, Faculty of System Design, Tokyo Metropolitan University, Tokyo, Japan.
authors: Hiromichi
authors: H
authors: Fujie
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D064594:Bone-Patellar Tendon-Bone Grafts; D002102:Cadaver; D005269:Femur / Q000601:surgery*; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery