The Influence of Graft Tensioning Sequence on Tibiofemoral Orientation During Bicruciate and Posterolateral Corner Knee Ligament Reconstruction: A Biomechanical Study

Abstract

Background: During multiple knee ligament reconstructions, the graft tensioning order may influence the final tibiofemoral orientation and corresponding knee kinematics. Nonanatomic tibiofemoral orientation may result in residual knee instability, altered joint loading, and an increased propensity for graft failure. Purpose: To biomechanically evaluate the effect of different graft tensioning sequences on knee tibiofemoral orientation after multiple knee ligament reconstructions in a bicruciate ligament (anterior cruciate ligament [ACL] and posterior cruciate ligament [PCL]) with a posterolateral corner (PLC)–injured knee. Study Design: Controlled laboratory study. Methods: Ten nonpaired, fresh-frozen human cadaveric knees were utilized for this study. After reconstruction of both cruciate ligaments and the PLC and proximal graft fixation, each knee was randomly assigned to each of 4 graft tensioning order groups: (1) PCL → ACL → PLC, (2) PCL → PLC → ACL, (3) PLC → ACL → PCL, and (4) ACL → PCL → PLC. Tibiofemoral orientation after graft tensioning was measured and compared with the intact state. Results: Tensioning the ACL first (tensioning order 4) resulted in posterior displacement of the tibia at 0° by 1.7 ± 1.3 mm compared with the intact state ( P = .002). All tensioning orders resulted in significantly increased tibial anterior translation compared with the intact state at higher flexion angles ranging from 2.7 mm to 3.2 mm at 60° and from 3.1 mm to 3.4 mm at 90° for tensioning orders 1 and 2, respectively (all P < .001). There was no significant difference in tibiofemoral orientation in the sagittal plane between the tensioning orders at higher flexion angles. All tensioning orders resulted in increased tibial internal rotation (all P < .001). Tensioning and fixing the PLC first (tensioning order 3) resulted in the most increases in internal rotation of the tibia: 2.4° ± 1.9°, 2.7° ± 1.8°, and 2.0° ± 2.0° at 0°, 30°, and 60°, respectively. Conclusion: None of the tensioning orders restored intact knee tibiofemoral orientation. Tensioning the PLC first should be avoided in bicruciate knee ligament reconstruction with concurrent PLC reconstruction because it significantly increased tibial internal rotation. We recommend that the PCL be tensioned first, followed by the ACL, to avoid posterior translation of the tibia in extension where the knee is primarily loaded during most activities. The PLC should be tensioned last. Clinical Relevance: This study will help guide surgeons in decision making for the graft tensioning order during multiple knee ligament reconstructions.