Comparison of tunnel positions in single-bundle anterior cruciate ligament reconstructions using computer navigation

Recurrent rotational instability has been identified as a potential source of failure of anterior cruciate ligament (ACL) reconstructions. The aim of the study was to assess whether knee kinematics in the horizontal configuration more closely resemble the intact knee when compared with other single-bundle configurations. Using the Praxim computer navigation system, ACL reconstructions were performed with tibialis anterior grafts in six fresh-frozen whole lower extremity cadaver specimens (12 knees). In each knee, all four reconstruction configurations: conventional (PL tibia to AM femur), anteromedial (AM), posterolateral (PL), and horizontal (AM tibia to PL femur) were performed. Standardized Lachman and pivot shift examinations were performed. For all graft positions during the pivot shift, decreases in the amount of ATT were observed compared with the ACL-deficient state. The knees with grafts placed in the anterior tibial footprint (AM and horizontal) had less ATT with the Lachman and pivot shift maneuvers than knees with grafts placed in the posterior tibial footprint (PL and conventional). A significant difference in depth of impingement was noted only between the AM position and the PL position. Single-bundle ACL reconstructions using graft placement within the anterior footprint on the tibia may reduce rotational instability when compared with more vertical configurations.