Am. J. Sports Med., May 2005; 33: 712-18.

Musahl V, Plakseychuk A, VanScyoc A, Sasaki T, Debski RE, McMahon PJ, Fu FH.


Background: Knee kinematics and in situ forces resulting from anterior cruciate ligament reconstructions with 2 femoral tunnel positions were evaluated.

Hypothesis: A graft placed inside the anatomical footprint of the anterior cruciate ligament will restore knee function better than a graft placed at a position for best graft isometry.

Study Design: Controlled laboratory study.

Methods: Ten cadaveric knees were tested in response to a 134-N anterior load and a combined 10-Nám valgus and 5-Nám internal rotation load. A robotic universal force-moment sensor testing system was used to apply loads, and resulting kinematics were recorded. An active surgical robot system was used for positioning tunnels in 2 locations in the femoral notch: inside the anatomical footprint of the anterior cruciate ligament and a position for best graft isometry. The same quadrupled hamstring tendon graft was used for both tunnel positions. The 2 loading conditions were applied.

Results: At 30ˇ of knee flexion, anterior tibial translation in response to the anterior load for the intact knee was 9.8 ± 3.1 mm. Both femoral tunnel positions resulted in significantly higher anterior tibial translation (position 1: 13.8 ± 4.6 mm; position 2: 16.6 ± 3.7 mm; P < .05). There was a significant difference between the 2 tunnel positions. At the same flexion angle, the anterior tibial translation in response to the combined load for the intact knee was 7.7 ± 4.0 mm. Both femoral tunnel positions resulted in significantly higher anterior tibial translation (position 1: 10.4 ± 5.5 mm; position 2: 12.0 ± 5.2 mm; P < .05), with a significant difference between the tunnel positions.

Conclusion: Neither femoral tunnel position restores normal kinematics of the intact knee. A femoral tunnel position inside the anatomical footprint of the anterior cruciate ligament results in knee kinematics closer to the intact knee than does a tunnel position located for best graft isometry.

Clinical Relevance: Anatomical femoral tunnel position is important in reproducing function of the anterior cruciate ligament.