title: The Relationship Between ACL Femoral Tunnel Position and Postoperative MRI Signal Intensity.
abstract: BACKGROUND
  The purpose of this study was to find the ideal femoral tunnel position in single-bundle anterior cruciate ligament (ACL) reconstruction using three-dimensional computed tomography (3D-CT) by comparing clinical scores, stability of the knee joint, and graft signal intensity on follow-up magnetic resonance imaging (MRI). We hypothesized that positioning the femoral tunnel near the anteromedial bundle or center would lead to better results in terms of clinical outcomes and graft signal intensity on follow-up MRI than would positioning the tunnel near the posterolateral bundle.
  
  
  METHODS
  Two hundred patients underwent arthroscopic single-bundle ACL reconstruction with a soft-tissue graft; all patients had the same surgeon, surgical technique (anteromedial transportal technique), and rehabilitation protocol. Each patient underwent 3D-CT within 1 week after the operation and MRI at 1 year after the operation. Outcomes were evaluated in terms of clinical scores and the stability of the knee joint. We classified patients into three groups based on the femoral tunnel position: the anteromedial position group, the posterolateral position group, and the center position group. We evaluated graft signal intensity on follow-up MRI.
  
  
  RESULTS
  This study included 77 patients: 25 patients in the anteromedial position group, 15 patients in the posterolateral position group, and 33 patients in the center position group. Four patients had an eccentric tunnel position and were excluded. The 3 groups did not differ significantly (p > 0.05) in preoperative demographic characteristics. There were no significant differences (p > 0.05) between groups in clinical outcomes. However, patients in the anteromedial position group and in the center position group had better graft signal intensity on follow-up MRI than those in the posterolateral position group.
  
  
  CONCLUSIONS
  Positioning the femoral tunnel near the anteromedial bundle and center led to better graft signal intensity on follow-up MRI in anatomic single-bundle ACL reconstruction than did positioning the femoral tunnel near the posterolateral bundle. There were no differences in clinical scores or stability of the knee joint among the three groups.
  
  
  METHODS
  Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: 1Department of Orthopaedic Surgery, Graduate School (S.M.L.), College of Medicine (K.H.Y. and D.H.), Kyung Hee University, Seoul, South Korea 2Department of Orthopaedic Surgery, Kyung Hee University Hospital at Gangdong, Seoul, South Korea.
authors.forename: Se Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Kyoung Ho
authors.initials: KH
authors.lastname: Yoon
authors.forename: Sang Hak
authors.initials: SH
authors.lastname: Lee
authors.forename: Dong
authors.initials: D
authors.lastname: Hur
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D019737:Transplants / Q000000981:diagnostic imaging; D055815:Young Adult