Biomechanical Comparison of ACL-R Using an Iliotibial Band Autograft Reinforcement and Bone–Patellar Tendon–Bone Graft With and Without Lateral Extra-articular Tenodesis

Background: An alternative single-bundle anatomic anterior cruciate ligament (ACL) reconstruction (ACL-R) devised by the senior author comprised an anterolateral reinforcement using an iliotibial band (ITB) autograft. The knee biomechanics of this technique have not been compared with standard ACL-R methods. Purpose: To compare the knee kinematics of ACL-R using bone–patellar–tendon bone graft with lateral extra-articular tenodesis (BTB+LET) versus ITB ACL-R with anterolateral reinforcement. Study Design: Controlled laboratory study. Methods: A total of 20 unpaired fresh-frozen human cadaveric knees (mean age, 41.4 years) were tested using a robotic system under 3 loads: (1) 89-N anterior tibial (AT) load (at 0°-90° of flexion); (2) 5-Nm internal rotation (IR) tibial torque (0°-90° of flexion); and (3) a simulated pivot-shift (PS) load, as a combined 7-Nm valgus moment and 5-Nm IR torque (at 0°, 15°, and 30° of flexion). All knees were tested with the ACL intact; one ACL-R group (n = 10) was tested with ITB reconstruction, and the other group (n = 10) was tested with BTB graft reconstruction, both with (BTB+LET) and without a LET procedure. Results: Significantly less AT translation, IR, and tibial displacement during simulated PS were detected at all knee flexion angles in the ITB, BTB, and BTB+LET states compared with the ACL-deficient state ( P < .05). There was no statistically significant difference during AT loading, IR torque, and simulated PS between BTB and ITB states at all knee flexion angles ( P .05). In response to AT loading, significantly less translation was detected in the BTB+LET state compared with the ITB state at 15° (mean difference MD, 1.6 ± 0.7 mm; P = .048), 30° (MD, 1.8 ± 0.7 mm; P = .03), and 60° (MD, 1.5 ± 0.6 mm; P = .03) of knee flexion. In response to IR torque, the only statistically significant difference between ITB and intact state was at 0° of knee flexion. In response to simulated PS, significantly less tibial displacement was detected in the BTB+LET state compared with the intact state at 15° (MD, 1.7 ± 0.5 mm; P = .04) of knee flexion. Conclusion: BTB and ITB ACL-R both improved knee stability compared with the ACL-deficient state in response to AT, IR, and simulated PS loading; however, no method restored the intact ACL behavior. BTB+LET caused overconstraint at 15° of knee flexion during simulated PS loading. Clinical Relevance: ITB ACL-R provides an alternative technique to improve stability of the ACL-deficient knee.