title: Evaluation of femoral tunnel positioning using 3-dimensional computed tomography and radiographs after single bundle anterior cruciate ligament reconstruction with modified transtibial technique.
abstract: BACKGROUND
  The purpose of this study is to report a modified transtibial technique to approach the center of anatomical femoral footprint in anterior cruciate ligament (ACL) reconstruction and to investigate the accurate femoral tunnel position with 3-dimensional computed tomography (3D-CT) and radiography after reconstruction.
  
  
  METHODS
  From December 2010 to October 2011, we evaluated 98 patients who underwent primary ACL reconstruction using a modified transtibial technique to approach the center of anatomical femoral footprint in single bundle ACL reconstruction with hamstring autograft. Their femoral tunnel positions were investigated with 3D-CT and radiography postoperatively. Femoral tunnel angle was measured on the postoperative anteroposterior (AP) radiograph and the center of the femoral tunnel aperture on the lateral femoral condyle was assessed with 3D-CT according to the quadrant method by two orthopedic surgeons.
  
  
  RESULTS
  According to the quadrant method with 3D-CT, the femoral tunnel was measured at a mean of 32.94% ± 5.16% from the proximal condylar surface (parallel to the Blumensaat line) and 41.89% ± 5.58% from the notch roof (perpendicular to the Blumensaat line) with good interobserver (intraclass correlation coefficients [ICC], 0.766 and 0.793, respectively) and intraobserver reliability (ICC, 0.875 and 0.893, respectively). According to the radiographic measurement on the AP view, the femoral tunnel angles averaged 50.43° ± 7.04° (ICC, 0.783 and 0.911, respectively).
  
  
  CONCLUSIONS
  Our modified transtibial technique is anticipated to provide more anatomical placement of the femoral tunnel during ACL reconstruction than the former traditional transtibial techniques.
authors.affiliation: Department of Orthopedic Surgery, JAINMEDI Hospital, Goyang, Korea.
authors.forename: Sung Rak
authors.initials: SR
authors.lastname: Lee
authors.forename: Hyoung Won
authors.initials: HW
authors.lastname: Jang
authors.forename: Dhong Won
authors.initials: DW
authors.lastname: Lee
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Nam
authors.forename: Jeong Ku
authors.initials: JK
authors.lastname: Ha
authors.forename: Jin Goo
authors.initials: JG
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: 3-Dimensional computed tomography; Anterior cruciate ligament reconstruction; Femoral tunnel; Transtibial technique