Interbundle Impingement Pressure in Individualized and Nonindividualized Double-Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

Abstract

Background: Graft impingement is one of the main concerns in double-bundle anterior cruciate ligament reconstruction (DB-ACLR). Impingement between the anteromedial (AM) and posterolateral (PL) bundles has been postulated to cause graft deterioration or rerupture, but this has not been thoroughly investigated, and the interbundle impingement pressure (IIP) has not been well researched. Purpose: To determine the IIP between the AM and PL bundles in the native anterior cruciate ligament (ACL) and in DB-ACLR with individualized and nonindividualized double-tunnel placement. Study Design: Controlled laboratory study. Methods: A total of 30 fresh-frozen, nonpaired, human cadaveric knees were randomly divided into 3 groups of 10 knees: native intact ACL (NI group), DB-ACLR tunnel placement using the preserved remnant procedure (individualized reconstruction) (PR group), and DB-ACLR tunnel placement using the bony landmark procedure (nonindividualized reconstruction) (BL group). Pressure sensors were inserted between the AM and PL bundles. The knee was moved passively from full extension to full flexion, and the IIP between the 2 ACL bundles was measured every 15°. Similarly, the impingement pressure was measured between the ACL and intercondylar roof and between the ACL and posterior cruciate ligament (PCL). Results: No significant differences were found in the maximum, mean, or minimum ACL-roof and ACL-PCL impingement pressures among the 3 groups. The IIP significantly increased when the knee joint was flexed >120° in all 3 groups ( P < .001). Compared with the other 2 groups, the BL group had significantly higher maximum and mean IIP throughout the range of knee movement ( P < .001) and from maximum extension to 120° of flexion ( P < .001). The BL group also had significantly higher minimum IIP than the other 2 groups when knee flexion was >120° ( P < .001). No significant differences were seen in maximum, minimum, or mean IIP between the NI and PR groups. Conclusion: The PR procedure (individualized DB-ACLR) was more consistent with the interbundle biomechanical conditions of the native ACL, whereas the BL procedure (nonindividualized DB-ACLR) had higher maximum and mean IIP. The IIP was higher than the ACL–intercondylar roof or ACL-PCL pressures, and it increased significantly when knee flexion was >120°. Clinical Relevance: These data suggest that surgeons can perform individualized DB-ACLR using preserved remnants for tunnel placement as impingement-free DB-ACLR.