Evaluation of damage to trabecular bone of the osteoporotic human acetabulum at small strains using nonlinear micro-finite element analyses  

作　　者：DING Hai ZHU Zhen-an DAI Ke-rong 

机构地区：[1]Department of Orthopaedics, Ninth People's Hospital, ShanghaiJiao Tong University School of Medicine, Shanghai 200011, China

出　　处：《Chinese Medical Journal》2009年第17期2041-2047,共7页中华医学杂志（英文版）

摘　　要：Background With advance of age, alterations in bone quality, quantity and microarchitecture render osteoporotic trabecular bone become more sensitive to local failure. The aims of the present study were to clarify the extent to which the distribution of tissue-level stresses and strains was affected by structural changes and the extent to which osteoporotic acetabular trabecular bone was damaged at small strains. Methods Using a DAWING 4000A supercomputer, nonlinear micro-finite element （μFE） analyses were performed to calculate the tissue-level strains and stresses for each element in the trabecular bone of one osteoporotic acetabulum at small strains to quantify the tissue-level damage accumulation and mechanical properties. Results In contour plots of the tissue, maximum principal logarithmic strains, high tissue-level strains, both compressive and tensile, were observed in the osteoporotic trabecular bone at small apparent strains from 0.2% to 0.5% strain. The compressive apparent stress-strain curve showed typical nonlinear behavior and tangent modulus reduction with increasing strains. The microdamage curve suggested that microdamage began at 0.2% apparent strain in the osteoporotic trabecular bone and increased sharply, although very few microfractures occurred. The quartiles of the maximum principal logarithmic strains, minimum principal logarithmic strains and Von Mises stresses increased nonlinearly. For the inter-quartile range of the Von Mises stresses, a leap occurred at small strains ranging from 0.2% to 0.3% while microdamage commenced. Conclusions Extensive microdamage was primarily responsible for the large loss in apparent mechanical properties that occurred in the trabecular bone of the osteoporotic acetabulum at small strains. With increasing apparent strains, continuous nonlinear increments of tissue-level strains and stresses resulted in microdamage that propagated throughout the specimen with very few microfractures. Chin Med J 2009; 122（17）：2041-204 7Background With advance of age, alterations in bone quality, quantity and microarchitecture render osteoporotic trabecular bone become more sensitive to local failure. The aims of the present study were to clarify the extent to which the distribution of tissue-level stresses and strains was affected by structural changes and the extent to which osteoporotic acetabular trabecular bone was damaged at small strains. Methods Using a DAWING 4000A supercomputer, nonlinear micro-finite element （μFE） analyses were performed to calculate the tissue-level strains and stresses for each element in the trabecular bone of one osteoporotic acetabulum at small strains to quantify the tissue-level damage accumulation and mechanical properties. Results In contour plots of the tissue, maximum principal logarithmic strains, high tissue-level strains, both compressive and tensile, were observed in the osteoporotic trabecular bone at small apparent strains from 0.2% to 0.5% strain. The compressive apparent stress-strain curve showed typical nonlinear behavior and tangent modulus reduction with increasing strains. The microdamage curve suggested that microdamage began at 0.2% apparent strain in the osteoporotic trabecular bone and increased sharply, although very few microfractures occurred. The quartiles of the maximum principal logarithmic strains, minimum principal logarithmic strains and Von Mises stresses increased nonlinearly. For the inter-quartile range of the Von Mises stresses, a leap occurred at small strains ranging from 0.2% to 0.3% while microdamage commenced. Conclusions Extensive microdamage was primarily responsible for the large loss in apparent mechanical properties that occurred in the trabecular bone of the osteoporotic acetabulum at small strains. With increasing apparent strains, continuous nonlinear increments of tissue-level strains and stresses resulted in microdamage that propagated throughout the specimen with very few microfractures. Chin Med J 2009; 122（17）：2041-204 7

关 键 词：mechanical property trabecular bone nonlinear micro-finite element analysis ACETABULUM OSTEOPOROSIS 

分 类 号：R686[医药卫生—骨科学]