[Force measurement of reconstructed anterior cruciate ligament in relation to changes in length in experiments using...

The effects of tibial and femoral attachment sites on changes in length and force were investigated in ACL grafts, using eight cadaver knees. Two tibial and three femoral attachment sites were chosen, such as the anteromedial and central sites in the tibial insertion of the ACL, and the central and anterior-superior sites in the femoral insertion, as well as the over-the-top route. Changes in the length in all combinations of these attachment sites was measured from extension to 150 degrees flexion at 15 degrees intervals by the displacement of a cord 2 mm in diameter which simulated the graft. The holes through the attachment sites were then enlarged to accept a 6 mm wide LAD (Ligament Augmentation Device, 3M). The force in this LAD graft was measured over the same range of knee flexion using a buckle transducer for all combinations of sites. Changes in length and force were affected more by the femoral attachment site. There was a close correlation between length changes and force measurements except at a neighborhood of the full extension. Changes in force between a given combination of sites failed to show a reproducible pattern among the knees tested.