Department of Orthopaedic Medicine Center, Brain Hospital of Hunan Provincial (The Second People's Hospital of Hunan Province), Clinical Medical College of Hunan University of Chinese Medicine, Changsha, 410007, China.
Department of Nursing, The Third Xiangya Hospital of Central South University, Changsha, 410013, China.
J Orthop Surg Res. 2023 Oct 31;18(1):815. doi: 10.1186/s13018-023-04307-1.
At present, not all Type AO/OTA 42A2 open fractures can be treated by external fixation brackets, not to mention the inconvenience of this technique in clinical practice. External titanium alloy locking plates, which are lightweight and easy-to-operate, can be used as an alternative treatment option for such patients. However, there are few reports of finite element biomechanical analysis on the titanium alloy locking plates and fixation brackets being placed on the medial side of the tibial fracture. In this study, the biomechanical properties of titanium alloy locking plates and fixation brackets for treating Type AO/OTA 42A2 fractures were compared by applying the finite element method, and the results provided data support for the clinical application of the external titanium alloy locking plate technique.
Type AO/OTA 42A2 fracture models were constructed using CT data of a male volunteer for two external fixation techniques, namely the external titanium alloy locking plate technique and the external fixation bracket technique, according to commonly-used clinical protocols. Then, the four-point bending, axial compression, clockwise rotation and counterclockwise rotation tests under the maximum load were simulated in finite element analysis software. The stress distribution, peak stress and overall tibial displacement data for the two different external fixation techniques were obtained and compared.
In the four different test conditions (i.e., four-point bending, axial compression, clockwise torsion, counterclockwise torsion) under the maximum load, the two external fixation techniques showed obvious von Mises stress concentration at the contacts between the screw and tibia, between the screw and titanium alloy locking plate, between the self-tapping self-drilling needle and tibia, between the self-tapping self-drilling needle and the external fixation device, as well as around the fracture end and around the cortical bone at the upper and lower ends of the tibia. The peak stress was ranged 26.67-558.77 MPa, all below the yield stress strength of titanium alloy. The peak tibial displacement of the external titanium alloy locking plate model was smaller than that of the fixation bracket model. In terms of structural stability, the external titanium alloy locking plate technique was superior to the external fixation bracket technique.
When fixing Type AO/OTA 42A2 fractures, external titanium alloy locking plates are not only lightweight and easy-to-operate, but also have better performance in terms of axial compression, bending and torsion resistance. According to the finite element biomechanical analysis, external titanium alloy locking plates are superior to traditional external fixation brackets in treating Type AO/OTA 42A2 fractures and can better meet the needs of clinical application.
目前，并非所有 A0/OTA 42A2 型开放性骨折都可以采用外固定架治疗，更不用说这种技术在临床实践中的不便了。轻巧易用的外固定钛合金锁定板可以作为此类患者的另一种治疗选择。但是，关于将钛合金锁定板和固定支架放置在胫骨骨折内侧的有限元生物力学分析的报道很少。在这项研究中，通过有限元法比较了钛合金锁定板和固定支架治疗 A0/OTA 42A2 型骨折的生物力学特性，为临床应用外固定钛合金锁定板技术提供了数据支持。
根据常用的临床方案，使用男性志愿者的 CT 数据构建 A0/OTA 42A2 骨折模型，采用两种外固定技术，即外固定钛合金锁定板技术和外固定架技术。然后，在有限元分析软件中模拟四点弯曲、轴向压缩、顺时针旋转和逆时针旋转下的最大载荷试验。获得并比较了两种不同外固定技术的应力分布、峰值应力和整体胫骨位移数据。
在最大载荷下的四种不同测试条件（即四点弯曲、轴向压缩、顺时针扭转、逆时针扭转）下，两种外固定技术在螺钉与胫骨、螺钉与钛合金锁定板、自攻自钻针与胫骨、自攻自钻针与外固定装置之间以及骨折端周围和胫骨上下两端皮质骨周围均出现明显的 Von Mises 压应力集中。峰值应力范围为 26.67-558.77MPa，均低于钛合金的屈服强度。钛合金锁定板外固定模型的胫骨峰值位移小于固定支架模型。在结构稳定性方面，外固定钛合金锁定板技术优于外固定架技术。
在固定 A0/OTA 42A2 型骨折时，外固定钛合金锁定板不仅轻巧易用，而且在轴向压缩、弯曲和抗扭转方面性能更好。根据有限元生物力学分析，外固定钛合金锁定板在治疗 A0/OTA 42A2 型骨折方面优于传统外固定架，能更好地满足临床应用的需要。
