Intraoperative laxity measurements using a navigation system in anatomical double-bundle posterior cruciate ligament reconstruction.

Abstract

The objective of this study was to evaluate knee kinematics during double-bundle posterior cruciate ligament reconstruction (DB-PCLR) intraoperatively using a navigation system, and especially assess biomechanical behaviour of the anterolateral bundle (ALB) and posteromedial bundle (PMB) graft in DB-PCLR. Also, clinical results of minimum 2-year follow-up were investigated. Nine patients received DB-PCLR with hamstring graft. Before reconstruction, knee laxities, including posterior tibial translation (PTT) in neutral rotation at 15°, 30°, 45°, 60°, 75° and 90° of knee flexion, were measured using a kinematic-based navigation system. After the PMB or ALB was temporally fixed, the knee laxities were measured in the same manner. Each patient was evaluated pre- and post-operatively with side-to-side difference of tibial position in gravity sag view and Lysholm score. Both ALB and PMB fixation restrained the PTT compared to  PCL deficiency throughout all knee flexion angles. At 90° of knee flexion, ALB fixation significantly decreased PTT compare to PMB fixation (p = 0.014) and DB-PCLR significantly decreased PTT compare to ALB fixation (p = 0.045). The mean side-to-side difference of tibial position in gravity sag view was 12.0 ± 1.7 mm preoperatively and 2.3 ± 1.8 mm at final follow-up, and the mean Lysholm scores were 68.9 ± 20.9 and 96.3 ± 2.9, respectively. There were no significant differences in the PTT between ALB and PMB fixations at 0° to 75° of knee flexion, and both ALB and PMB reconstructions are important for restraining PTT. At 90° of knee flexion, the ALB grafts may be more important to control PTT compared to PMB grafts; however, neither single-bundle reconstruction with ALB nor PMB could function as DB-PCLR did. In addition, PTT after DB-PCLR was strongly correlated side-to-side difference in posterior sag view at the final follow-up. The results from this study indicated that both ALB and PMB are important to stabilize PCL-deficient knees. Therapeutic study, Level III.