基于 MRI 的有限元分析评估人体股骨近端多尺度力学行为随年龄和加载状态的变化。

In Vivo Assessment of Age- and Loading Configuration-Related Changes in Multiscale Mechanical Behavior of the Human Proximal Femur Using MRI-Based Finite Element Analysis.

机构信息

Department of Biomedical Engineering, Faculty of Environment and Life Science, Beijing University of Technology, Beijing, China.

Department of Radiology, Beijing Jishuitan Hospital, Beijing, China.

出版信息

J Magn Reson Imaging. 2021 Mar;53(3):905-912. doi: 10.1002/jmri.27403. Epub 2020 Oct 19.

DOI:10.1002/jmri.27403

PMID:33075178

Abstract

BACKGROUND

MRI-based finite element analysis (MRI-FEA) is the only method able to assess microstructural and whole-bone mechanical properties of the hip in vivo.

PURPOSE

To examine whether MRI-FEA is capable of discriminating age-related changes in whole-bone mechanical performance and micromechanical behavior of the proximal femur, particularly considering the most common hip fracture-related sideways fall loading.

STUDY TYPE

Retrospective.

SUBJECTS

A total of nine younger (27 ± 3.2 years) and nine elderly (61 ± 3.9 years) healthy volunteers.

FIELD STRENGTH/SEQUENCE: 3T; 3D fast field echo sequence.

ASSESSMENT

The left proximal femurs were scanned and FE models created. FEA was performed to simulate sideways fall and stance loading for each femoral model. Apparent stiffness and high-risk (90th percentile) tensile and compressive strains of the proximal femur as well as the average strains within cubic regions of the femoral neck and greater trochanter were assessed.

STATISTICAL TESTS

Paired and unpaired t-tests.

RESULTS

Compared to the young group, the femoral stiffness of the elderly decreased by 39% and 40% (both P < 0.05) under the sideways fall and stance conditions, respectively. Accordingly, the high-risk tensile and compressive stains were elevated with aging (40% and 23% for sideways fall, 23% and 11% for stance conditions; all P < 0.05). However, the loading configuration-induced difference was only observed in the elderly group for the high-risk strains (22% for tension and 12% for compression; both P < 0.05). Additionally, compared to the stance condition, the sideways fall increased the average tensile (young: 108%, elderly: 123%; both P < 0.05) and compressive strains (young: 631%, elderly: 617%, both P < 0.05) within the greater trochanter rather than the femoral neck region.

DATA CONCLUSION

In vivo MRI-FEA is capable of capturing age-related changes in both apparent-level stiffness and tissue-level micromechanical behavior of the proximal femur. However, the effect of sideways fall loading might be better reflected by tissue-level micromechanics rather than apparent stiffness.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 1.

摘要

背景

基于 MRI 的有限元分析（MRI-FEA）是唯一能够评估髋关节体内微观结构和整体骨骼力学性能的方法。

目的

探讨 MRI-FEA 是否能够区分与年龄相关的整体骨骼力学性能变化和股骨近端的微观力学行为，特别是考虑到最常见的髋关节骨折相关的侧方跌倒负荷。

研究类型

回顾性。

受试者

共 9 名年轻（27 ± 3.2 岁）和 9 名老年（61 ± 3.9 岁）健康志愿者。

场强/序列：3T；3D 快速场回波序列。

评估

对左侧股骨近端进行扫描并创建 FE 模型。对每个股骨模型进行 FEA 模拟侧方跌倒和站立负荷。评估股骨近端的表观刚度和高风险（90 百分位）拉伸和压缩应变以及股骨颈和大转子立方区域内的平均应变。

统计学检验

配对和非配对 t 检验。

结果

与年轻组相比，老年组在侧方跌倒和站立条件下的股骨刚度分别降低了 39%和 40%（均 P<0.05）。相应地，高风险拉伸和压缩应变随年龄增长而升高（侧方跌倒时为 40%和 23%，站立时为 23%和 11%；均 P<0.05）。然而，仅在老年组中观察到加载配置引起的高风险应变差异（拉伸时为 22%，压缩时为 12%；均 P<0.05）。此外，与站立条件相比，侧方跌倒增加了大转子区域内的平均拉伸（年轻：108%，老年：123%；均 P<0.05）和压缩应变（年轻：631%，老年：617%；均 P<0.05），而不是股骨颈区域。