title: Femoral tunnel placement during anterior cruciate ligament reconstruction: an in vivo imaging analysis comparing transtibial and 2-incision tibial tunnel-independent techniques.
abstract: BACKGROUND
  Recent studies have questioned the ability of the transtibial technique to place the anterior cruciate ligament graft within the footprint of the anterior cruciate ligament on the femur. There are limited data directly comparing the abilities of transtibial and tibial tunnel-independent techniques to place the graft anatomically at the femoral attachment site of the anterior cruciate ligament in patients.
  
  
  OBJECTIVE
  Because placement with the tibial tunnel-independent technique is unconstrained by the tibial tunnel, it would allow for more anatomic tunnel placement compared with the transtibial technique.
  
  
  METHODS
  Cross-sectional study; Level of evidence, 3.
  
  
  METHODS
  High-resolution, multiplanar magnetic resonance imaging and advanced 3-dimensional modeling techniques were used to measure in vivo femoral tunnel placement in 8 patients with the transtibial technique and 8 patients with a tibial tunnel-independent technique. Femoral tunnel placement in 3 dimensions was measured relative to the center of the native anterior cruciate ligament attachment on the intact contralateral knee.
  
  
  RESULTS
  The tibial tunnel-independent technique placed the graft closer to the center of the native anterior cruciate ligament attachment compared with the transtibial technique. The transtibial technique placed the tunnel center an average of 9 mm from the center of the anterior cruciate ligament attachment, compared with 3 mm for the tibial tunnel-independent technique. The transtibial technique resulted in a more anterior and superior placement of the tunnel compared with the tibial tunnel- independent technique.
  
  
  CONCLUSIONS
  The tibial tunnel-independent technique allowed for more anatomic femoral tunnel placement compared with the transtibial technique.
authors.affiliation: Sports Medicine Center, Division of Orthopaedics, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27705, USA.
authors.forename: Ermias S
authors.initials: ES
authors.lastname: Abebe
authors.forename: C T
authors.initials: CT
authors.lastname: Moorman
authors.forename: T Scott
authors.initials: TS
authors.lastname: Dziedzic
authors.forename: Charles E
authors.initials: CE
authors.lastname: Spritzer
authors.forename: R Lee
authors.initials: RL
authors.lastname: Cothran
authors.forename: Dean C
authors.initials: DC
authors.lastname: Taylor
authors.forename: William E
authors.initials: WE
authors.lastname: Garrett
authors.forename: Louis E
authors.initials: LE
authors.lastname: DeFrate
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D054544:Arthroplasty, Subchondral / Q000379:methods*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013977:Tibia / Q000601:surgery*; D055815:Young Adult