胫骨近端联合截骨术内固定钢板系统的有限元仿真

基于胫骨近端联合截骨术（CPTO）治疗内翻型膝骨性关节炎的手术方案，采用有限元方法研究CPTO治疗中两种常用的内固定钢板系统对其生物力学特性的影响。建立胫骨近端联合截骨术植入Tomofix和Tomofix亚洲型内固定钢板系统的三维有限元模型，比较分析膝关节的刚度和楔形位移，以及植入器械的应力分布特征。研究结果表明，在CPTO手术中使用Tomofix亚洲型内固定系统相比使用Tomofix内固定系统的膝关节刚度增加了23.8%，平均楔形位移降低了85.5%，骨骼平均应力降低了36.5%，钢板和螺钉的最大应力分别增加了16.6%和4.6%。因此，在CPTO手术中使用Tomofix亚洲型内固定系统能较有效地提高膝关节结构的稳定性，减小楔形微动，为骨愈合提供强有力的支撑，但在内固定系统的高强度支撑下骨骼应力降低较明显，有引发应力遮挡效应进而导致骨质疏松的风险。

Finite element simulation of internal fixation plate system in combined proximal tibial osteotomy

Based on the surgical program of the combined proximal tibial osteotomy (CPTO) to treat varus knee osteoarthritis, the biomechanical properties of two common internal fixation systems in CPTO with finite element analysis were studied. The three-dimentional finite element model of proximal tibial osteotomy combined with Tomofix and Tomofix-Asian internal fixation systems were established, the knee joint stiffness, wedge displacement and the stress distribution of tibia and implants were compared. The results show that the stiffness and the average wedge displacement increase by 23.8% and -85.5% respectively, using Tomofix-Asian internal fixation system compared with Tomofix internal fixation system. The average stress on tibia decreases by 36.5%, and the maximum stresses on plate and screw increase by 16.6% and 4.6%, respectively. Therefore, the Tomofix-Asian internal fixation system usage during CPTO can improve the knee joint stability, reduce the wedge displacement, and provide strong support for bone healing. However, the obvious decrease of bone stress due to the high-strength support of the internal fixation system may increase the risk of stress shielding effect leading to osteoporosis.