Foot and Ankle Research and Innovation Lab (FARIL), Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Department of Orthopaedics and Traumatology, Ghent University Hospital, Ghent, Belgium.
Foot Ankle Int. 2024 Apr;45(4):393-405. doi: 10.1177/10711007241227179. Epub 2024 Feb 25.
Talar displacement is considered the main predictive factor for poor outcomes and the development of post-traumatic osteoarthritis after ankle fractures. Isolated lateral talar translation, as previously studied by Ramsey and Hamilton using carbon powder imprinting, does not fully replicate the multidirectional joint subluxations seen in ankle fractures. The purpose of this study was to analyze the influence of multiple uniplanar talar displacements on tibiotalar contact mechanics utilizing weightbearing computed tomography (WBCT) and finite element analysis (FEA).
Nineteen subjects (mean age = 37.6 years) with no history of ankle surgery or injury having undergone WBCT arthrogram (n = 1) and WBCT without arthrogram (n = 18) were included. Segmentation of the WBCT images into 3D simulated models of bone and cartilage was performed. Three-dimensional (3D) multiple uniplanar talar displacements were simulated to investigate the respective influence of various uniaxial displacements (including lateral translation, anteroposterior translation, varus-valgus angulation, and external rotation) on the tibiotalar contact mechanics using FEA. Tibiotalar peak contact stress and contact area were modeled for each displacement and its gradations.
Our modeling demonstrated that peak contact stress of the talus and tibia increased, whereas contact area decreased, with incremental displacement in all tested directions. Contact stress maps of the talus and tibia were computed for each displacement demonstrating unique patterns of pressure derangement. One millimeter of lateral translation resulted in 14% increase of peak talar contact pressure and a 3% decrease in contact area.
Our model predicted that with lateral talar translation, there is less noticeable change in tibiotalar contact area compared with prior studies whereas external rotation greater than 12 degrees had the largest effect on peak contact stress predictions.
Level V, computational simulation study.
距骨位移被认为是预测踝关节骨折后预后不良和创伤后骨关节炎发展的主要因素。正如 Ramsey 和 Hamilton 之前使用碳粉印迹研究的那样，单纯的外侧距骨平移并不能完全复制踝关节骨折中所见的多方向关节半脱位。本研究旨在利用负重 CT（WBCT）和有限元分析（FEA）分析多种单平面距骨位移对距骨 - 胫骨接触力学的影响。
19 名受试者（平均年龄 37.6 岁）无踝关节手术或损伤史，分别进行了 WBCT 关节造影术（n=1）和 WBCT 无关节造影术（n=18）。将 WBCT 图像分割成骨骼和软骨的 3D 模拟模型。模拟了三维（3D）多平面距骨位移，以研究各种单轴位移（包括外侧平移、前后平移、内翻 - 外翻角度和外旋）对 FEA 中距骨 - 胫骨接触力学的各自影响。为每个位移及其梯度模拟了距骨和胫骨的最大接触压力和接触面积。
我们的模型表明，在所有测试方向上，距骨和胫骨的最大接触压力增加，而接触面积减小。为每个位移计算了距骨和胫骨的接触压力图，显示出压力紊乱的独特模式。1 毫米的外侧平移导致距骨最大接触压力增加 14%，接触面积减少 3%。
我们的模型预测，与外侧距骨平移相比，距骨 - 胫骨接触面积的变化不太明显，而大于 12 度的外旋对最大接触压力预测的影响最大。
5 级，计算模拟研究。
