EFFECT OF ANTERIOR CRUCIATE LIGAMENT GRAFT TENSIONING DIRECTION, MAGNITUDE, AND FLEXION ANGLE ON KNEE BIOMECHANICS

The objective of this study was to determine the biomechanical effect of graft tensioning during reconstruction of the anterior cruciate lig ament. We evaluated the magnitude of the tensioning force (22 or 67 N) , the flexion angle at which the tension was applied (extension or 300 of flexion), and the direction of application of the tensioning force (proximal, distal, or distal with a posterior force simultaneously ap plied to the tibia) on 10 fresh cadaveric knees. The anterior cruciate ligament was reconstructed using a bone-patellar tendon-bone graft. T he graft was then temporarily fixed during the application of each of 12 combinations of tensioning variables listed above. After each fixat ion, graft force and joint motion were measured during anterior tibial loads. Tensioning direction and the flexion angle significantly affec ted graft force and joint motion, while the magnitude of the graft ten sioning did not. Graft forces were greater when the tensioning was app lied at 300 of flexion. Compared with distal tensioning with and witho ut posterior tibial force, graft forces with proximal tensioning were greater in extension and lower in flexion. The position of the tibia r elative to the femur was posterior and externally rotated, compared wi th normal, for all combinations of tensioning variables in both unload ed and anterior load states.