Rush University Medical Center, Chicago, Illinois.
Twin Cities Orthopedics, Edina, Minnesota, U.S.A.
Arthroscopy. 2020 Feb;36(2):333-335. doi: 10.1016/j.arthro.2019.12.013. Epub 2019 Dec 24.
Improved understanding of the anatomy and biomechanics of the posterior cruciate ligament (PCL) has led to the evolution and improvement of anatomic-based reconstructions. The PCL is composed of the larger anterolateral bundle (ALB) and the smaller posteromedial bundle (PMB). On the femoral side, the ALB spans from the trochlear point to the medial arch point on the roof of the notch, while the PMB occupies the medial wall from the medial arch point to the most posterior aspect of the articular cartilage. Because of these broad and distinct attachments, the bundles have a load-sharing, synergistic and codominant relationship. Both restrict posterior translation; however, the ALB has a proportionally larger role in restricting translation throughout flexion, whereas the PMB has a role comparable to that of the ALB in full extension. In addition, the PMB resists internal rotational at greater flexion angles (> 90°). Consequently, it is difficult to restore native kinematics with a single graft. Biomechanical analysis of single- versus double-bundle PCL reconstructions (SB PCLR vs DB PCLR) demonstrates improved restoration of native kinematics with a DB PCLR, including resistance to posterior translation throughout flexion (15°-120°) and internal rotation in deeper flexion (90°-120°). Similarly, clinical research demonstrates excellent outcomes following DB PCLR, including functional outcomes comparable to those of anterior cruciate ligament reconstructions, with no significant differences between isolated and multiligament PCL injuries. Compared to SB PCLR, systematic review has demonstrated the superiority of DB PCLR based on objective postoperative stress radiography and International Knee Documentation Committee scores in randomized trials. In addition to reconstruction techniques, recent research has identified other factors that impact kinematics and PCL forces, including decreased tibial slope, which leads to increased graft stresses, and incidence of native PCL injuries. As the understanding of these other contributing factors evolves, so will surgical and treatment algorithms that will further improve patients' outcomes.
对后交叉韧带 (PCL) 的解剖结构和生物力学的深入了解，推动了解剖重建的发展和改进。PCL 由较大的前外侧束 (ALB) 和较小的后内侧束 (PMB) 组成。在股骨侧，ALB 从滑车点延伸到切迹顶的内侧拱点，而 PMB 占据内侧壁从内侧拱点到关节软骨的最后部。由于这些广泛而明显的附着点，束之间存在着负荷分担、协同和共同主导的关系。两者都限制了后向平移；然而，ALB 在整个弯曲过程中对限制平移的作用更大，而 PMB 在完全伸展时的作用与 ALB 相当。此外，PMB 在更大的弯曲角度（>90°）时抵抗内旋。因此，很难用单个移植物恢复正常的运动学。对单束与双束后交叉韧带重建术 (SB PCLR 与 DB PCLR) 的生物力学分析表明，DB PCLR 可更好地恢复正常的运动学，包括在整个弯曲过程中（15°-120°）抵抗后向平移和在更深的弯曲时（90°-120°）抵抗内旋。同样，临床研究表明，DB PCLR 后效果极佳，包括与前交叉韧带重建术相当的功能结果，且在孤立性和多韧带 PCL 损伤之间无显著差异。与 SB PCLR 相比，系统评价基于随机试验中的客观术后应力射线照相和国际膝关节文献委员会评分，证明了 DB PCLR 的优越性。除了重建技术，最近的研究还确定了其他影响运动学和 PCL 力的因素，包括胫骨斜率减小，这会导致移植物应力增加，以及原发性 PCL 损伤的发生率。随着对这些其他因素的了解不断深入，手术和治疗方案也将进一步改善患者的治疗效果。
