title: Optimal entry position on the lateral femoral surface for outside-in drilling technique to restore the anatomical footprint of anterior cruciate ligament.
abstract: OBJECTIVE
  To investigate the optimal starting points for drilling on the lateral femoral condyle for better coverage of the anatomical footprint of the anterior cruciate ligament (ACL) using the outside-in (OI) technique in a single-bundle ACL reconstruction.
  
  
  METHODS
  Femoral tunnel drilling was simulated on three-dimensional bone models from 40 subjects by connecting the centre of the ACL footprint with various points on the lateral femoral surface. The percentage of the femoral footprint covered by apertures of the virtual tunnel sockets with 9 mm diameter was calculated for each tunnel.
  
  
  RESULTS
  The mean percentages of the femoral footprint covered by the apertures of the virtual tunnel sockets were significantly higher when drilled at 2 and 3 cm from the lateral epicondyle on a 45° line and a 60° line anterior from the proximal-distal axis than the other points. However, articular cartilage damage was occurred in nine subjects at 3 cm on a 60° line and eight subjects at 3 cm on a 45° line. Posterior wall blowout occurred in five subjects at 3 cm on a 45° line. Thus, OI drilling at 3 cm from the epicondyle has a risk of these complications.
  
  
  CONCLUSIONS
  During the OI drilling of the femoral tunnel, connecting the centre of the anatomical footprint of the ACL and the entry drilling point at 2 cm from the lateral epicondyle on between the 45° line and the 60° line anterior from the proximal-distal axis provides an oval-shaped socket aperture that covers and restores the native ACL footprint as nearly as possible.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Matsubara
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan. okazaki@med.kyushu-u.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Okazaki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Kanji
authors.initials: K
authors.lastname: Osaki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Tashiro
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Mizu-Uchi
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamai
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-0054, Japan.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000601:surgery; D003198:Computer Simulation; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D014057:Tomography, X-Ray Computed
keywords: Anterior cruciate ligament (ACL) reconstruction; Arthroscopy; Computer simulation; Surgical technique