Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia.
Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia; School of Allied Health Sciences, Griffith University, Gold Coast, Australia; The Bone Clinic, Brisbane, Australia.
J Biomech. 2021 Apr 15;119:110315. doi: 10.1016/j.jbiomech.2021.110315. Epub 2021 Feb 9.
Physical exercise induces spatially heterogeneous bone changes in the proximal femur. Recent advances have enabled 3D dual-energy X-ray Absorptiometry (DXA)-based finite element (FE) models to estimate bone strength. However, its ability to detect exercise-induced BMD and strength changes is unclear. The aim of this study was to quantify the repeatability of vBMD and femoral neck strength obtained from 3D-DXA images and determine the changes due an exercise intervention. The DXA scans included pairs of same-day repeated scans from ten healthy females and pre- and post-exercise intervention scans of 26 males. FE models with element-by-element correspondence were generated by morphing a template mesh to each bone. BMD and femoral strength under single-leg-stance and sideways fall loading configurations were obtained for both groups and compared. In the repeated images, the total hip vBMD difference was 0.5 ± 2.5%. Element-by-element BMD differences reached 30 ± 50%. The strength difference in single-leg stance was 2.8 ± 13% and in sideways fall was 4.5% ± 19%. In the exercise group, strength changes were 6 ± 19% under single-leg stance and 1 ± 18% under sideways fall. vBMD parameters were weakly correlated to strength (R < 0.31). The exercise group had a mean bone accrual exceeding repeatability values in the femoral head and cortical regions. The case with the highest vBMD change (6.4%) caused 18% and -7% strength changes under single-leg stance and sideways fall. 3D-DXA technology can assess the effect of exercise interventions in large cohorts but its validity in individual cases should be interpreted with caution.
体育锻炼会导致股骨近端的骨变化具有空间异质性。最近的进展使基于三维双能 X 射线吸收法（DXA）的有限元（FE）模型能够估计骨强度。然而，其检测运动引起的 BMD 和强度变化的能力尚不清楚。本研究的目的是量化从三维 DXA 图像获得的 vBMD 和股骨颈强度的可重复性，并确定运动干预引起的变化。DXA 扫描包括 10 名健康女性同一天重复扫描的对和 26 名男性运动干预前后的扫描。通过将模板网格变形到每个骨骼来生成具有元素对元素对应关系的 FE 模型。对两组分别获得单腿站立和侧跌加载配置下的 BMD 和股骨强度，并进行比较。在重复图像中，总髋部 vBMD 差异为 0.5 ± 2.5%。元素对元素的 BMD 差异达到 30 ± 50%。单腿站立的强度差异为 2.8 ± 13%，侧跌为 4.5% ± 19%。在运动组中，单腿站立的强度变化为 6 ± 19%，侧跌为 1 ± 18%。vBMD 参数与强度的相关性较弱（R < 0.31）。运动组在股骨头和皮质区域的骨积累平均值超过了可重复性值。vBMD 变化最大的病例（6.4%）导致单腿站立和侧跌的强度变化分别为 18%和-7%。3D-DXA 技术可以评估大样本运动干预的效果，但在个体情况下的有效性应谨慎解释。
