Peersman Geert, Slane Josh, Dirckx Margo, Vandevyver Arne, Dworschak Philipp, Heyse Thomas J, Scheys Lennart
ZNA Stuivenberg, Antwerp, Belgium; Institute for Orthopaedic Research and Training, KU Leuven/UZ Leuven, Campus Pellenberg, Leuven, Belgium.
Institute for Orthopaedic Research and Training, KU Leuven/UZ Leuven, Campus Pellenberg, Leuven, Belgium.
Knee. 2017 Aug;24(4):751-760. doi: 10.1016/j.knee.2017.03.010. Epub 2017 Apr 19.
The recently reintroduced bicruciate retaining Total Knee Arthroplasty (BCR TKA) is an effort to reproduce kinematics closer to the native knee. However, there is no data on appropriate balancing with this implant. Balancing is crucial and challenging as medial and lateral polyethylene (PE) inlays are modular, which allows for placement of different thicknesses in the medial and lateral compartments. This study aimed at providing a detailed kinematic view on balancing BCR TKA.
Seven fresh frozen cadaver legs were mounted in a kinematic rig that applied squatting under application of physiologic quadriceps and hamstring forces. Additionally, specimen laxity was assessed using Lachman tests and varus/valgus stress tests. Following testing on the native knee, a BCR TKA was implanted in each specimen and all trials were repeated. Using one millimeter increments, five inlay thicknesses were tested to simulate optimal balancing, symmetric under-, and overstuffing, valgus constellation, and varus constellation.
Overall, knee kinematics following BCR TKA seem to be very close to the native knee. The changes as introduced to tibiofemoral kinematics through over- or understuffing the polyethylene inserts are affecting the system only to a minor degree and generally lack statistical significance. Reproduction of the tibial varus via PE-Inlays did not lead to kinematics much closer to the native knee.
The changes introduced to tibiofemoral kinematics by removal of the conforming meniscus and cartilage and replacement with a flat PE insert and femoral component are of more impact than different inlay sizes and their combinations for a BCR TKA.
最近重新引入的双交叉保留型全膝关节置换术（BCR TKA）旨在使膝关节运动学更接近天然膝关节。然而，关于这种植入物的合适平衡尚无数据。平衡至关重要且具有挑战性，因为内侧和外侧聚乙烯（PE）嵌体是模块化的，这使得可以在内侧和外侧间室放置不同厚度的嵌体。本研究旨在提供关于BCR TKA平衡的详细运动学观点。
将七条新鲜冷冻的尸体腿安装在一个运动装置中，该装置在施加生理股四头肌和腘绳肌力量的情况下进行下蹲动作。此外，使用拉赫曼试验和内翻/外翻应力试验评估标本的松弛度。在对天然膝关节进行测试后，在每个标本中植入BCR TKA，并重复所有试验。以一毫米的增量测试五种嵌体厚度，以模拟最佳平衡、对称填充不足和过度填充、外翻构型和内翻构型。
总体而言，BCR TKA后的膝关节运动学似乎非常接近天然膝关节。通过聚乙烯插入物过度填充或填充不足引入到胫股关节运动学中的变化仅在很小程度上影响系统，并且通常缺乏统计学意义。通过PE嵌体再现胫骨内翻并未导致运动学更接近天然膝关节。
对于BCR TKA，去除顺应性半月板和软骨并用平坦的PE插入物和股骨部件进行置换所引入的胫股关节运动学变化，比不同嵌体尺寸及其组合的影响更大。
