建立肥胖老年人特定个体近端股骨有限元模型以评估体重减轻对骨强度的影响。
Development of Subject-Specific Proximal Femur Finite Element Models Of Older Adults with Obesity to Evaluate the Effects of Weight Loss on Bone Strength.
作者信息
Schoell S L, Weaver A A, Beavers D P, Lenchik Leon, Marsh A P, Rejeski W J, Stitzel J D, Beavers K M
机构信息
Department of Biomedical Engineering, Wake Forest School of Medicine, USA.
Department of Biostatistical Sciences, Wake Forest School of Medicine, USA.
出版信息
J Osteoporos Phys Act. 2018;6(1). doi: 10.4172/2329-9509.1000213. Epub 2018 Mar 8.
STUDY BACKGROUND
Recommendation of intentional weight loss in older adults remains controversial, due in part to the loss of bone mineral density (BMD) known to accompany weight loss. While finite element (FE) models have been used to assess bone strength, these methods have not been used to study the effects of weight loss. The purpose of this study is to develop subject-specific FE models of the proximal femur and study the effect of intentional weight loss on bone strength.
METHODS
Computed tomography (CT) scans of the proximal femur of 25 overweight and obese (mean BMI=29.7 ± 4.0 kg/m), older adults (mean age=65.6 ± 4.1 years) undergoing an 18-month intentional weight loss intervention were obtained at baseline and post-intervention. Measures of volumetric BMD (vBMD) and variable cortical thickness were derived from each subject CT scan and directly mapped to baseline and post-intervention models. Subject-specific FE models were developed using morphing techniques. Bone strength was estimated through simulation of a single-limb stance and sideways fall configuration.
RESULTS
After weight loss intervention, there were significant decreases from baseline to 18 months in vBMD (total hip: -0.024 ± 0.013 g/cm; femoral neck: -0.012 ± 0.014 g/cm), cortical thickness (total hip: -0.044 ± 0.032 mm; femoral neck: -0.026 ± 0.039 mm), and estimated strength (stance: -0.15 ± 0.12 kN; fall: -0.04 ± 0.06 kN). Adjusting for baseline bone measures, body mass, and gender, correlations were found between weight change and change in total hip and femoral neck cortical thickness (all p<0.05). For every 1 kilogram of body mass lost cortical thickness in the total hip and femoral neck decreased by 0.003 mm and 0.004 mm, respectively. No significant correlations were present for the vBMD or strength data.
CONCLUSION
The developed subject-specific FE models could be used to better understand the effects of intentional weight loss on bone health.
研究背景
建议老年人进行有意的体重减轻仍存在争议，部分原因是已知体重减轻会伴随骨矿物质密度（BMD）的流失。虽然有限元（FE）模型已被用于评估骨骼强度，但这些方法尚未用于研究体重减轻的影响。本研究的目的是建立特定个体的股骨近端有限元模型，并研究有意体重减轻对骨骼强度的影响。
方法
对25名超重和肥胖（平均BMI = 29.7 ± 4.0 kg/m）的老年人（平均年龄 = 65.6 ± 4.1岁）进行18个月的有意体重减轻干预，在基线和干预后获得其股骨近端的计算机断层扫描（CT）图像。从每个受试者的CT扫描中得出体积骨密度（vBMD）和可变皮质厚度的测量值，并直接映射到基线和干预后的模型中。使用变形技术建立特定个体的有限元模型。通过模拟单腿站立和侧向跌倒姿势来估计骨骼强度。
结果
体重减轻干预后，从基线到18个月，vBMD（全髋：-0.024 ± 0.013 g/cm；股骨颈：-0.012 ± 0.014 g/cm）、皮质厚度（全髋：-0.044 ± 0.032 mm；股骨颈：-0.026 ± 0.039 mm）和估计强度（站立：-0.15 ± 0.12 kN；跌倒：-0.04 ± 0.06 kN）均显著下降。在调整了基线骨测量、体重和性别后，发现体重变化与全髋和股骨颈皮质厚度变化之间存在相关性（所有p<0.05）。每减轻1千克体重，全髋和股骨颈的皮质厚度分别减少0.003 mm和0.004 mm。vBMD或强度数据之间无显著相关性。
结论
所建立的特定个体有限元模型可用于更好地理解有意体重减轻对骨骼健康的影响。
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