Analysis of bone formation around the ankie after total ankie replacement using cell-automaton method

1)考虑膝关节、踝关节和距下关节之间的相互作用，对下肢关节面周围进行应力分析。定量分析了几何参数对关节突应力的影响。最后，提出了膝关节截骨术截骨角度的优化方法。采用有限元分析方法研究了膝关节骨性关节炎和踝关节的力学行为。很明显，每个关节的力学环境相互作用。提出了一种SOM优化方法对膝关节的力学条件进行定量研究，以膝关节内侧的接触合力为关节力学条件的关键目标函数，建立了基于SOM的P估计表达式，并在此基础上，对于膝关节骨关节炎，最佳截骨角度α为20.4 °，对于膝关节骨关节炎伴同侧踝关节骨关节炎，最佳截骨角度α为22.3 °。2）对奈良大学研制的人工全踝关节系统的踝关节周围及胫骨部件表面进行应力分析，以分散应力集中。采用有限元法和SOM优化方法，发现随着锚宽度的增加，胫骨假体的性能得到改善15.6mm，高度4.5mm，倾斜度60 °。

1) Stress analysis around facets of the lower limb considering the interaction between the knee joint, ankle joint and the subtalar joint was performed. Quantative estimation of the effect of the geometric parameters on the stress on the facet was secondary analized. And fnally, development of a optimization method of the osteotomy angle for the knee osteotomy.Finite element analysis was used to study the mechanical behavior for the knee and ankle joints of osteoarthritis. It was made clear that the mechanical environment of each joint interacted with one another. An optimization method of SOM was proposed to carry out a quantatitive atudy of the mechanical conditions of the joint, and the resultant contact force on the medial of the knee was evaluated as the key objective function of the mechanical condition for the joint, and an estimation expression of P was established using SOM.Based upon the expression of P, the optimum angles alpha of the osteotomy were calcukated to be 20.4 degrees for the case of knee osteoarthritis, and to be 22.3 degrees for the case of knee osteoarthritis accompanied by ipsilateral ankle osteoarthritis. It was found that these values of alpha correspond very well with the clinical examples.2) Stress analysis was performed aroud the ankle joint and the surface of the tbial component of the artificial total ankle system produced by Nara University to disperse * the stress concentration, using finite element method and the optimization method of SOM.It was found that the tibial component would be improved with the width of the anchor was 15.6mm, hight was 4.5mm and slope was 60 degrees.