Institute of Metal Forming and Metal-Forming Machines, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany.
Biomed Eng Online. 2011 Jul 5;10:58. doi: 10.1186/1475-925X-10-58.
The use of artificial endoprostheses has become a routine procedure for knee and hip joints while ankle arthritis has traditionally been treated by means of arthrodesis. Due to its advantages, the implantation of endoprostheses is constantly increasing. While finite element analyses (FEA) of strain-adaptive bone remodelling have been carried out for the hip joint in previous studies, to our knowledge there are no investigations that have considered remodelling processes of the ankle joint. In order to evaluate and optimise new generation implants of the ankle joint, as well as to gain additional knowledge regarding the biomechanics, strain-adaptive bone remodelling has been calculated separately for the tibia and the talus after providing them with an implant.
FE models of the bone-implant assembly for both the tibia and the talus have been developed. Bone characteristics such as the density distribution have been applied corresponding to CT scans. A force of 5,200 N, which corresponds to the compression force during normal walking of a person with a weight of 100 kg according to Stauffer et al., has been used in the simulation. The bone adaptation law, previously developed by our research team, has been used for the calculation of the remodelling processes.
A total bone mass loss of 2% in the tibia and 13% in the talus was calculated. The greater decline of density in the talus is due to its smaller size compared to the relatively large implant dimensions causing remodelling processes in the whole bone tissue. In the tibia, bone remodelling processes are only calculated in areas adjacent to the implant. Thus, a smaller bone mass loss than in the talus can be expected. There is a high agreement between the simulation results in the distal tibia and the literature regarding.
In this study, strain-adaptive bone remodelling processes are simulated using the FE method. The results contribute to a better understanding of the biomechanical behaviour of the ankle joint and hence are useful for the optimisation of the implant geometry in the future.
膝关节和髋关节已普遍采用人工假体，而踝关节关节炎传统上采用关节融合术治疗。由于其优势，假体的植入不断增加。虽然之前的研究已经对髋关节进行了应变适应性骨重塑的有限元分析（FEA），但据我们所知，还没有研究考虑踝关节的重塑过程。为了评估和优化新一代踝关节假体，并进一步了解生物力学，在为胫骨和距骨提供假体后，分别对胫骨和距骨进行了应变适应性骨重塑计算。
为胫骨和距骨的骨-假体组件开发了 FE 模型。根据 CT 扫描应用了骨特征，如密度分布。根据 Stauffer 等人的研究，模拟中使用了 5200N 的力，这相当于体重为 100kg 的人在正常行走时的压缩力。我们研究团队之前开发的骨适应定律用于计算重塑过程。
计算出胫骨的总骨量损失为 2%，距骨的总骨量损失为 13%。距骨密度下降较大，是因为与相对较大的植入物尺寸相比，其尺寸较小，导致整个骨组织发生重塑过程。在胫骨中，仅在毗邻植入物的区域计算骨重塑过程。因此，预计骨量损失会比距骨小。胫骨远端的模拟结果与文献高度一致。
本研究采用有限元法模拟了应变适应性骨重塑过程。研究结果有助于更好地了解踝关节的生物力学行为，从而有助于未来优化植入物的几何形状。
