Robert F. LaPrade, Steadman Philippon Research Institute, 181 West Meadow Drive, Suite 1000, Vail, CO 81657.
Am J Sports Med. 2013 Dec;41(12):2828-38. doi: 10.1177/0363546513504287. Epub 2013 Sep 24.
The posterior cruciate ligament (PCL) is composed of 2 functional bundles and has an essential role in knee function and stability. There is, however, a limited understanding of the role of each individual bundle through the full range of knee flexion.
Both bundles provide restraint to posterior tibial translation across a full range of knee flexion. At higher angles of knee flexion (>90°), the intact PCL also imparts significant rotational stability.
Controlled laboratory study.
Twenty matched-paired, human cadaveric knees (mean age, 55.2 years; range, 51-59 years; 6 male and 4 female pairs) were used to evaluate the kinematics of an intact, anterolateral bundle (ALB) sectioned, posteromedial bundle (PMB) sectioned, and complete PCL sectioned knee. A 6 degree of freedom robotic system was used to assess knee stability with an applied 134-N posterior tibial load, 5-N·m external and internal rotation torques, 10-N·m valgus and varus torques, and a coupled 100-N posterior tibial load and 5-N external rotation torque at 0°, 15°, 30°, 45°, 60°, 75°, 90°, 105°, and 120°.
All sectioned states had significant increases compared with intact in posterior translation, internal rotation, and external rotation at all tested flexion angles, with the exception of the ALB sectioned state at 75° of flexion for external rotation. The significant increases (mean ± standard deviation) in posterior translation during a 134-N posterior tibial load at 90° of flexion were 0.9 ± 0.6 mm, 2.6 ± 1.8 mm, and 11.7 ± 4.0 mm for the PMB, ALB, and complete PCL sectioned states, respectively, compared with the intact state. The largest significant increases in internal rotation were in the PMB and complete PCL sectioned states at 105° of flexion, 1.3° ± 1.0° and 2.8° ± 2.1°, respectively.
Both the ALB and the PMB assume a significant role in resisting posterior tibial translation, at all flexion angles, suggesting a codominant relationship. The PCL provided a significant constraint to internal rotation beyond 90° of flexion.
This information broadens the understanding of native knee kinematics and provides a template for the evaluation of single- and double-bundle PCL reconstructions.
后交叉韧带（PCL）由 2 个功能束组成，对膝关节功能和稳定性起着重要作用。然而，对于整个膝关节屈伸范围内每个束的作用，我们的了解有限。
两个束都对整个膝关节屈伸范围内的胫骨后移提供限制。在更高的膝关节角度（>90°）时，完整的 PCL 也会产生显著的旋转稳定性。
对照实验室研究。
使用 20 对匹配的人尸体膝关节（平均年龄 55.2 岁；范围 51-59 岁；6 对男性和 4 对女性）评估完整的、前外侧束（ALB）切断、后内侧束（PMB）切断和完全切断的 PCL 膝关节的运动学。使用 6 自由度机器人系统在施加 134-N 胫骨后向负荷、5-N·m 外旋和内旋扭矩、10-N·m 外翻和内翻扭矩以及 100-N 胫骨后向负荷和 5-N 外旋扭矩的情况下评估膝关节稳定性，外加 5-N·外旋扭矩，在 0°、15°、30°、45°、60°、75°、90°、105°和 120°处。
与完整状态相比，所有切断状态在所有测试的膝关节角度下，后移、内旋和外旋都有显著增加，除了在 75°的外旋时的 ALB 切断状态。在 90°的膝关节屈曲时，施加 134-N 胫骨后向负荷时，后移的显著增加（平均值±标准差）分别为 0.9±0.6mm、2.6±1.8mm 和 11.7±4.0mm，分别为 PMB、ALB 和完整 PCL 切断状态。在 105°的膝关节屈曲时，最大的内旋显著增加分别见于 PMB 和完整 PCL 切断状态，为 1.3°±1.0°和 2.8°±2.1°。
ALB 和 PMB 在所有膝关节屈伸角度下都对胫骨后移有显著的抵抗作用，提示存在协同作用。PCL 在超过 90°的膝关节屈曲时对内部旋转提供了显著的限制。
这些信息拓宽了对膝关节自然运动学的理解，并为单束和双束 PCL 重建的评估提供了模板。
