title: Femoral graft bending angle and femoral tunnel geometry of transportal and outside-in techniques in anterior cruciate ligament reconstruction: an in vivo 3-dimensional computed tomography analysis.
abstract: OBJECTIVE
  To compare femoral graft bending angles and femoral tunnel geometries between the transportal (TP) and outside-in (OI) techniques after anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.
  
  
  METHODS
  Thirty-nine patients underwent DB ACL reconstruction with the TP and OI techniques. They were randomized on the day of surgery to either the TP group (group I, 21 cases) or the OI group (group II, 18 cases). Femoral graft bending angle, femoral tunnel geometry, posterior wall breakage, and tunnel communication were assessed by computed tomography imaging with OsiriX imaging software (Pixmeo, Geneva, Switzerland).
  
  
  RESULTS
  The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angles of group II (97.3° ± 8.3° and 97.4° ± 8.6°, respectively) were significantly more acute than those of group I (108.2° ± 8.4° and 109.9° ± 8.8°, respectively) (P < .001). The mean AM femoral tunnel length of group II (34.3 ± 3.9 mm) was significantly longer than that of group I (31.9 ± 2.7 mm) (P = .02). However, the mean PL femoral tunnel lengths did not differ between groups. In 7 cases-4 cases (19.0%) in group I and 3 cases (16.6%) in group II-the femoral tunnel communication was found around the intra-articular aperture. Posterior wall breakage was observed in 5 cases (23.8%), which were all in AM femoral tunnels of group I.
  
  
  CONCLUSIONS
  The OI technique resulted in more acute femoral graft bending angles (difference of 10.9° and 12.5° for AM and PL, respectively) and longer mean AM femoral tunnel lengths (difference of 2.4 mm) than the TP technique after anatomic DB ACL reconstruction, even though these small differences might be unlikely to be of clinical significance. Femoral tunnel communication was found in both groups, and posterior wall breakage was observed in AM femoral tunnels with the TP technique.
  
  
  METHODS
  Level I, prospective randomized trial.
authors.affiliation: Department of Orthopedic Surgery, Korea University College of Medicine, Guro Hospital, Seoul, South Korea.
authors.forename: Jae Gyoon
authors.initials: JG
authors.lastname: Kim
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Wang
authors.forename: Hong Chul
authors.initials: HC
authors.lastname: Lim
authors.forename: Jin Hwan
authors.initials: JH
authors.lastname: Ahn
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging* / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D019651:Plastic Surgery Procedures / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult