title: Evaluation of the semitendinosus tendon graft shift in the bone tunnel: an experimental study.
abstract: OBJECTIVE
  The purpose of this study was to measure the semitendinosus tendon graft shift at the tunnel aperture with graft bending using a simulated femoral bone tunnel.
  
  
  METHODS
  Eight semitendinosus tendon grafts were used in this study. The median age of the specimen was 53 years (range 46-63). After stripping excess soft tissue, the semitendinosus tendon was doubled over the loop of the EndoButton CL (Smith and Nephew Inc.). The diameter of the graft was measured using a graft-sizing tube (Smith and Nephew Inc.) and verified to be 7.0 mm. A custom-made aluminium fixture, the size was 40.0 mm(3), with 7.0-mm-diameter hole was used as a simulated femoral bone tunnel. The graft was inserted to the tunnel, and EndoButton was positioned to the outside of the tunnel on the fixture. The distal end of the graft was tensioned with 30 N at an angle of 15°, 30°, 45°, 60°, 75° that reproduced the graft bending angle during knee range of motion. The photograph of the tunnel aperture was taken at each graft bending angle using a digital camera, and the graft shift amount in the simulated tunnel was analysed using the computer software (ImageJ).
  
  
  RESULTS
  The amount of the graft shift significantly increased when the graft bending angle was increased (P < 0.05). The biggest shift was observed when the graft bending angle was 75° in all specimens, and the value was 1.10 mm ± 0.12.
  
  
  CONCLUSIONS
  The present study suggests that even if the femoral tunnel was created in the centre of the ACL insertion site, the graft shifted within the tunnel in the direction of the tension applied to the graft during knee range of motion. Surgeons may have to consider the graft shift within the bone tunnel as well as the tunnel position in the restoration of the native ACL anatomy.
authors.affiliation: Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. nzsnow_iox@yahoo.co.jp.|Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA. nzsnow_iox@yahoo.co.jp.
authors.forename: Masataka
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Orthopaedic Surgery, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Orthopaedic Surgery, Kobe University, Kobe, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Araki
authors.affiliation: Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. matino@md.okayama-u.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Furumatsu
authors.affiliation: Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Miyazawa
authors.affiliation: Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Ozaki
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Linde-Rosen
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Smolinski
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
mesh_terms: D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002102:Cadaver; D005260:Female; D005269:Femur / Q000601:surgery*; D000070632:Hamstring Tendons / Q000637:transplantation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019737:Transplants / Q000637:transplantation*
keywords: Anterior cruciate ligament (ACL); Femoral tunnel; Graft shift; Soft tissue graft