Chang Chih-Wei, Chen Yen-Nien, Li Chun-Ting, Chung Chi-Rung, Chang Chih-Han, Peng Yao-Te
1 Department of Biomedical Engineering, National Cheng Kung University, Tainan City.
2 Department of Orthopedics, College of Medicine, National Cheng Kung University, Tainan City.
J Orthop Surg (Hong Kong). 2019 Sep-Dec;27(3):2309499019861145. doi: 10.1177/2309499019861145.
Tibial tubercle osteotomy (TTO) is a surgical technique used in the management of severe fractures of the knee joint and revision total knee arthroplasty. Limited research discusses the performance of the osteotomy and fixation of the TTO with screws. Therefore, this study investigated the effects of fragment shape and screw configuration on the mechanical behavior in the fixation of the TTO using the finite element (FE) method.
FE TTO models with three fragment shapes and three screw configurations were developed. The three fragment shapes were a step cut, bevel cut, and straight cut. The screw configurations were two parallel horizontal and downward screws and two trapezoidal screws. A 1654-N upward tension force was applied on the tibia tubercle, and the distal end of the tibia was completely fixed.
The results indicated that the step cut resulted in higher stability than the bevel and straight cut, but the stress was higher as well. Among the screw configurations, two parallel downward screws resulted in the highest stability, given the same fragment shape. In the horizontal configuration, the step cut tibia developed the largest contact force to achieve stability of the bone fragment under loading.
The fragment shape with a step cut and fixation with two parallel horizontal or downward screws are suggested for TTO, while the trapezoidal screw configuration is not suggested. Furthermore, the downward screw configuration is a suitable strategy to reduce bone stress.
胫骨结节截骨术（TTO）是一种用于治疗膝关节严重骨折和全膝关节置换翻修术的外科技术。关于使用螺钉进行TTO截骨术和固定的性能的研究有限。因此，本研究使用有限元（FE）方法研究了骨块形状和螺钉配置对TTO固定中力学行为的影响。
建立了具有三种骨块形状和三种螺钉配置的FE TTO模型。三种骨块形状为阶梯状截骨、斜切和直切。螺钉配置为两根平行的水平向下螺钉和两根梯形螺钉。在胫骨结节上施加1654 N的向上拉力，胫骨远端完全固定。
结果表明，阶梯状截骨比斜切和直切具有更高的稳定性，但应力也更高。在相同的骨块形状下，在螺钉配置中，两根平行向下的螺钉具有最高的稳定性。在水平配置中，阶梯状截骨的胫骨在加载时产生最大的接触力以实现骨块的稳定。
建议TTO采用阶梯状截骨形状并用两根平行的水平或向下螺钉固定，不建议采用梯形螺钉配置。此外，向下的螺钉配置是降低骨应力的合适策略。
