Kinematics of the Posterior Cruciate Ligament/Posterolateral Corner-Injured Knee After Reconstruction by Single- and Double-Bundle Intra-articular Grafts

Background: Single- and double-bundle reconstructions have been proposed for the knee after combined posterior cruciate ligament/posterolateral corner injuries.

Hypothesis: The double-bundle posterior cruciate ligament reconstruction is superior to the single-bundle posterior cruciate ligament reconstruction with regard to restoration of normal knee kinematics to the posterior cruciate ligament/posterolateral corner-sectioned knee.

Study Design: Controlled laboratory study.

Methods: Kinematics of 8 fresh-frozen, cadaveric human knees were determined in the following conditions: intact, sectioned posterior cruciate ligament/posterolateral corner, single anterolateral bundle posterior cruciate reconstruction, and double-bundle posterior cruciate reconstruction.

Results: The sectioned knee demonstrated a posterior shift of the tibial neutral position and the abnormal posterior, varus, and external rotation laxities used clinically to define a combined posterior cruciate ligament/posterolateral corner injury. Both reconstructions restored the posterior laxity to levels that were not statistically different from those seen in the intact knee, but the double-bundle reconstruction more closely mimicked the posterior laxity profile of the intact knee, having statistically lower posterior laxities than did the single-bundle reconstruction at 30°, 60°, and 90° of flexion (P < .05, analysis of variance, HSD test). The resting position of the tibia after double-bundle reconstruction trended to be anteriorly subluxated relative to its position for the intact knee at flexion angles of 30° and greater (P < .05, paired t test). Neither technique corrected the abnormal varus or external rotation laxities.

Conclusion: With either single- or double-bundle reconstructions, additional posterolateral reconstruction is recommended to correct the external rotation laxity.

Clinical Relevance: Knowledge of the kinematics of the combined posterior cruciate ligament/posterolateral corner-injured knee is important in the proper diagnosis of the injury and in the selection of the appropriate surgical reconstruction.