Varus malalignment of the tibia could alter ankle biomechanics, and might lead to degenerative changes of the ankle joint. However, previous studies failed to report the detailed changes of ankle biomechanics in varus malalignment of the tibia. The aim of this biomechanical study was to evaluate how the ankle joint pressure would change in response to the incremental increases in varus malalignment of the tibia. Eight fresh-frozen human cadaver legs were tested in this study. Varus malalignment of the tibia and a total of 600 N compressive force was simulated using a custom made fixture. Intra-articular sensors (TeckScan) were inserted in the ankle joint to collect the ankle joint pressure data. The testing sequence was 0°, 2°,4°,6°,8°,10°,12°,14°,16°,18°,20° of tibial varus. As the tibial varus progressed, the center of force (COF) shifted laterally both for the medial and lateral aspect of the ankle joint. For the medial aspect of the ankle joint, the lateral shift reached its maximum at 8° [2.76 (1.62) mm, p = 0.002] of tibial varus, while for the lateral aspect of the ankle joint, the lateral shift reached its maximum at 12° [2.11 (1.19) mm, p = 0.002] of tibial varus. Thereafter, the COF shifted medially as the tibial varus progressed. For the lateral aspect of the ankle joint, The Pmean increased from 2103.8 (625.1) kPa at 0° to 2295.3 (589.7) kPa at 8° of tibial varus (p = 0.047), significant difference was found between the Pmean at 0° and 8° (p = 0.047) of tibial varus. Then as the tibial varus progressed, the Pmean decreased to 1748.9 (467.2) kPa at 20° of tibial varus (p = 0.002). The lateral joint pressure ratio also increased from 0.481 (0.125) at 0° to 0.548 (0.108) at 10° of tibial varus (p = 0.002), then decreased to 0.517 (0.101) at 20° of tibial varus (p = 0.002) . For mild tibial varus deformities, there was a lateral shift of COF and lateral stress concentration within the ankle joint. However, as the tibial varus progressed, the COF shifted medially and the lateral stress concentration decreased.

中文翻译：

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踝关节压力变化在胫骨内翻畸形中

胫骨内翻畸形可能会改变踝关节的生物力学，并可能导致踝关节的退行性改变。但是，先前的研究未能报告踝关节生物力学在胫骨内翻畸形中的详细变化。这项生物力学研究的目的是评估随着胫骨内翻畸形的增加而引起的踝关节压力变化。在这项研究中测试了八只新鲜冷冻的人尸体腿。使用定制的夹具模拟胫骨的内翻畸形和总共600 N的压缩力。将关节​​内传感器（TeckScan）插入踝关节以收集踝关节压力数据。测试顺序为胫骨内翻0°，2°，4°，6°，8°，10°，12°，14°，16°，18°，20°。随着胫骨内翻的发展，力中心（COF）在踝关节的内侧和外侧都向外侧移动。对于踝关节的内侧，外侧移位在胫骨内翻8°[2.76（1.62）mm，p = 0.002]处达到最大，而对于踝关节的外侧，外侧移位在8°处达到最大。 12°[2.11（1.19）mm，p = 0.002]胫骨内翻。此后，随着胫骨内翻的进行，COF向内移动。对于踝关节的外侧方面，Pmean从0°的2103.8（625.1）kPa增加到8°胫骨内翻的2295.3（589.7）kPa（p = 0.047），在0°的Pmean和0°的Pmean之间存在显着差异。 8°（p = 0.047）胫骨内翻。然后，随着胫骨内翻的进行，Pmean在胫骨内翻20°下降至1748.9（467.2）kPa（p = 0.002）。横向接头压力比也从0增加。0°时为481（0.125），胫骨内翻为10°时为0.548（0.108）（p = 0.002），然后胫骨内翻20°时为0.517（0.101）（p = 0.002）。对于轻度胫骨内翻畸形，踝关节内存在COF侧移和侧向应力集中。但是，随着胫骨内翻的进行，COF向内移动，侧向应力集中减小。