Bicruciate lesion biomechanics, Part 2-treatment using a simultaneous tensioning protocol: ACL fixation first is better than PCL fixation first to restore tibiofemoral orientation.

PURPOSE: An uncommon technique for bicruciate ligament reconstruction involving simultaneous tensioning of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) grafts with ACL graft fixation first has been pointed out as superior to the "gold-standard" PCL graft fixation first. The purpose of this study was to compare tibiofemoral biomechanics between ACL fixation first and PCL fixation first in a simultaneous tensioning protocol for bicruciate ligament reconstruction.

METHODS: 12 fresh-frozen cadaveric knees (six matched pairs) were tested using a custom testing system. Neutral tibial position representing tibiofemoral orientation, anterior-posterior (AP) tibial translation, varus-valgus laxity, and internal-external rotation were measured using a Microscribe 3DLX at 0°, 30°, 60°, and 90° of knee flexion. The following knee conditions were evaluated: intact, bicruciate deficient and following bicruciate reconstruction. A simultaneous tensioning protocol was used for bicruciate reconstruction and PCL fixation first was compared to ACL fixation first. PCL graft fixation was always performed at 90° of flexion and ACL graft fixation was always performed at full extension.

RESULTS: ACL fixation first achieved a tibiofemoral orientation closer to the intact knee than PCL fixation first at 90° flexion (1.8 ± 1.6 mm versus 6.1 ± 3.2 mm, p = 0.016). PCL fixation first had a larger decrease in AP translation than ACL fixation first at 30° flexion (64.6 ± 3.5% vs. 58.3 ± 2.4%, p = 0.01). No significant differences were found for varus/valgus, external-internal rotation decrements after bicruciate reconstruction nor for AP translation, varus/valgus and internal/external rotation increase after bicruciate lesion comparing ACL fixation first to PCL fixation first.

CONCLUSION: Bicruciate ligament reconstruction using a simultaneous tensioning protocol with ACL fixation first resulted in a closer to normal tibiofemoral orientation. This study will help guide surgeons in decision making for the graft tensioning protocol and fixation sequence in a bicruciate ligament reconstruction.

LEVEL OF EVIDENCE: V therapeutic study.