The effect of femoral tunnel placement on ACL graft orientation and length during in vivo knee flexion.

Journal Article (Journal Article)

Anatomically placed grafts are believed to more closely restore the function of the ACL. This study measured the effect of femoral tunnel placement on graft orientation and length during weight-bearing flexion. Both knees of twelve patients where the graft was placed near the anteroproximal border of the ACL and ten where the graft was placed near the center of the ACL were imaged using MR. These images were used to create 3D models of the reconstructed and intact contralateral knees, including the attachment sites of the native ACL and graft. Next, patients were imaged using biplanar fluoroscopy while performing a quasi-static lunge. The models were registered to the fluoroscopic images to reproduce in vivo knee motion. From the relative motion of the attachment sites on the models, the length and orientation of the graft and native ACL were measured. Grafts placed anteroproximally on the femur were longer and more vertical than the native ACL in both the sagittal and coronal planes, while anatomically placed grafts more closely mimicked ACL motion. In full extension, the grafts placed anteroproximally were 12.3±5.2° (mean and 95%CI) more vertical than the native ACL in the sagittal plane, whereas the grafts placed anatomically were 2.9±3.7° less vertical. Grafts placed anteroproximally were up to 6±2 mm longer than the native ACL, while the anatomically placed grafts were a maximum of 2±2 mm longer. In conclusion, grafts placed anatomically more closely restored native ACL length and orientation. As a result, anatomic grafts are more likely to restore intact knee kinematics.

Full Text

Duke Authors

Cited Authors

  • Abebe, ES; Kim, J-P; Utturkar, GM; Taylor, DC; Spritzer, CE; Moorman, CT; Garrett, WE; DeFrate, LE

Published Date

  • July 7, 2011

Published In

Volume / Issue

  • 44 / 10

Start / End Page

  • 1914 - 1920

PubMed ID

  • 21570688

Pubmed Central ID

  • PMC3131226

Electronic International Standard Serial Number (EISSN)

  • 1873-2380

Digital Object Identifier (DOI)

  • 10.1016/j.jbiomech.2011.04.030


  • eng

Conference Location

  • United States