Abstract
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.