Anderson Donald D, Goldsworthy Jane K, Li Wendy, James Rudert M, Tochigi Yuki, Brown Thomas D
Department of Orthopaedics, University of Iowa, Iowa City, IA, USA; Biomedical Engineering, The University of Iowa, Iowa City, IA, USA.
J Biomech. 2007;40(8):1662-9. doi: 10.1016/j.jbiomech.2007.01.024. Epub 2007 Apr 12.
A validation study was conducted to determine the extent to which computational ankle contact finite element (FE) results agreed with experimentally measured tibio-talar contact stress. Two cadaver ankles were loaded in separate test sessions, during which ankle contact stresses were measured with a high-resolution (Tekscan) pressure sensor. Corresponding contact FE analyses were subsequently performed for comparison. The agreement was good between FE-computed and experimentally measured mean (3.2% discrepancy for one ankle, 19.3% for the other) and maximum (1.5% and 6.2%) contact stress, as well as for contact area (1.7% and 14.9%). There was also excellent agreement between histograms of fractional areas of cartilage experiencing specific ranges of contact stress. Finally, point-by-point comparisons between the computed and measured contact stress distributions over the articular surface showed substantial agreement, with correlation coefficients of 90% for one ankle and 86% for the other. In the past, general qualitative, but little direct quantitative agreement has been demonstrated with articular joint contact FE models. The methods used for this validation enable formal comparison of computational and experimental results, and open the way for objective statistical measures of regional correlation between FE-computed contact stress distributions from comparison articular joint surfaces (e.g., those from an intact versus those with residual intra-articular fracture incongruity).
进行了一项验证研究，以确定计算得到的踝关节接触有限元（FE）结果与实验测量的胫距接触应力的吻合程度。在单独的测试环节中对两具尸体踝关节进行加载，在此期间使用高分辨率（Tekscan）压力传感器测量踝关节接触应力。随后进行相应的接触有限元分析以作比较。有限元计算得到的和实验测量的平均接触应力（一个踝关节的差异为3.2%，另一个为19.3%）、最大接触应力（分别为1.5%和6.2%）以及接触面积（分别为1.7%和14.9%）之间吻合良好。经历特定接触应力范围的软骨部分面积的直方图之间也有极好的吻合。最后，计算得到的和测量得到的关节表面接触应力分布的逐点比较显示出高度吻合，一个踝关节的相关系数为90%，另一个为86%。过去，关节接触有限元模型已证明有一般的定性吻合，但很少有直接的定量吻合。用于此次验证的方法能够对计算结果和实验结果进行正式比较，并为对来自比较关节表面（例如，完整的与有残余关节内骨折不平整的）的有限元计算接触应力分布之间的区域相关性进行客观统计测量开辟了道路。
