title: Morphological changes in femoral tunnels after anatomic anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  Few studies investigated the enlargement inside the tunnel as well as the morphological change at the aperture after anterior cruciate ligament (ACL) reconstruction, whereas the tunnel enlargement has been well documented. The purposes were to evaluate the change in the cross-sectional area along the femoral tunnel and to morphologically clarify the enlargement at the femoral tunnel aperture after anatomic triple-bundle (ATB) ACL reconstruction.
  
  
  METHODS
  The study included 15 patients with unilateral ACL rupture. ATB ACL reconstruction was performed using semitendinosus tendon autografts. Three-dimensional computer models of the femur and bone tunnels were reconstructed from computed tomography images obtained 3 weeks and 1 year postoperatively. The cross-sectional area at the aperture as well as inside the tunnel was compared between the two periods. Likewise, the location of tunnel walls and center in the tunnel footprint were evaluated.
  
  
  RESULTS
  The cross-sectional area enlarged by 22.7 % for anteromedial/intermediate graft (P = 0.002) and 28.6 % for posterolateral graft (P = 0.002) at the aperture, while decreased by 36.2 % at 10 mm from the aperture for anteromedial/intermediate graft (P = 0.004). Both the anterior and posterior walls shifted anteriorly, while the distal wall shifted distally in both tunnels. Consequently, the center in the footprint significantly shifted anteriorly (4.9-6.6 %) and distally (2.2-2.6 %) in both tunnels.
  
  
  CONCLUSIONS
  The femoral tunnel enlargement occurred at the aperture after ATB ACL reconstruction, but did not occur in the middle of the femoral tunnel. The morphology at the aperture changed with time after surgery as the tunnel walls translated anteriorly and distally.
  
  
  METHODS
  Case series, Level IV.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Tachibana
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan. ta-mae@umin.ac.jp.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Mae
authors.affiliation: Sports Orthopaedic Surgery Center, Yukioka Hospital, 2-2-3 Ukita, Kita-ku, Osaka, Osaka, 530-0021, Japan.
authors.forename: Konsei
authors.initials: K
authors.lastname: Shino
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kanamoto
authors.affiliation: Department of Orthopaedic Biomaterial Science, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Sugamoto
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Nakata
mesh_terms: D000293:Adolescent; D000328:Adult; D019412:Anatomy, Cross-Sectional; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects*; D001168:Arthritis / Q000601:surgery; D003198:Computer Simulation; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: ACL; Anatomic; Cross-sectional area; Graft; Knee; Tunnel enlargement; Tunnel morphology