Heyse Thomas J, Slane Joshua, Peersman Geert, Dirckx Margo, van de Vyver Arne, Dworschak Philipp, Fuchs-Winkelmann Susanne, Scheys Lennart
Center of Orthopedics and Trauma Surgery, University Hospital Marburg, Baldingerstrasse, 35043, Marburg, Germany.
Department of Orthopaedics, Katholieke Universiteit Leuven, Campus Pellenberg, Louvain, Belgium.
Knee Surg Sports Traumatol Arthrosc. 2017 Jun;25(6):1784-1791. doi: 10.1007/s00167-016-4414-5. Epub 2017 Jan 11.
The recently reintroduced bicruciate-retaining Total Knee Arthroplasty (BCR TKA) is an interesting approach in the quest for close replication of knee joint biomechanics and kinematics closer to the native knee. Therefore, this study aimed at providing a detailed biomechanical view on the functional resemblance of BCR TKA to the native knee joint.
Seven fresh-frozen full leg cadaver specimens (76 ± 10 year) were mounted in a 6 degrees-of-freedom kinematic rig that applied a dynamic squatting motion knee flexion. Two motion patterns were performed pre- and post-implantation of a fixed bearing BCR TKA: passive flexion-extension and squatting while an infrared camera system tracked the location of reflective markers attached to the tibia and femur. Additionally, specimen laxity was assessed using Lachman tests and varus/valgus stress tests in triplicate.
Overall, differences in tibiofemoral kinematics between native knee and BCR TKA were small. Some minor differences appeared under the load of a squat: less internal tibial rotation and some minor paradoxical anterior translation of the medial femoral condyle during mid-flexion. BCR TKA may slightly elevate the joint line. Knee laxity as measured by the Lachman and varus/valgus tests was not significantly influenced by BCR TKA implantation.
As both cruciate ligaments are preserved with BCR TKA the unloaded knee closely resembles native knee kinematics including preserving the rollback mechanism. The loss of the conforming anatomy of menisci and tibial cartilage and replacement via a relatively flat polyethylene inlay may account for the loss of tibial internal rotation and the slight paradoxical AP motion of the medial femoral condyle with BCR TKA. This phenomenon reproduces findings made earlier with fixed bearing unicondylar knee arthroplasty.
最近重新引入的双交叉韧带保留型全膝关节置换术（BCR TKA）是一种旨在更接近自然膝关节的生物力学和运动学的有趣方法。因此，本研究旨在详细阐述BCR TKA与自然膝关节功能相似性的生物力学观点。
将七个新鲜冷冻的全腿尸体标本（76±10岁）安装在一个6自由度运动装置上，该装置可对膝关节进行动态下蹲运动的屈曲。在植入固定平台BCR TKA之前和之后进行两种运动模式：被动屈伸和下蹲，同时一个红外摄像系统跟踪附着在胫骨和股骨上的反光标记的位置。此外，使用拉赫曼试验和内翻/外翻应力试验对标本松弛度进行三次评估。
总体而言，自然膝关节和BCR TKA之间的胫股关节运动学差异较小。在下蹲负荷下出现了一些细微差异：胫骨内旋减少，以及在屈曲中期内侧股骨髁出现一些轻微的反常向前平移。BCR TKA可能会轻微抬高关节线。通过拉赫曼试验和内翻/外翻试验测量的膝关节松弛度不受BCR TKA植入的显著影响。
由于BCR TKA保留了两条交叉韧带，无负荷的膝关节与自然膝关节运动学非常相似，包括保留了后滚机制。半月板和胫骨软骨的顺应性解剖结构丧失，以及通过相对平坦的聚乙烯衬垫进行置换，可能是BCR TKA导致胫骨内旋丧失和内侧股骨髁轻微反常前后运动的原因。这一现象重现了早期固定平台单髁膝关节置换术的研究结果。
