Warden Stuart J, Fuchs Robyn K, Liu Ziyue, Toloday Katelynn R, Surowiec Rachel, Moe Sharon M
Department of Physical Therapy, School of Health and Human Sciences, Indiana University, Indianapolis, IN, United States of America.
Indiana Center for Musculoskeletal Health, Indiana University, IN, United States of America.
Bone Rep. 2024 Jan 6;20:101735. doi: 10.1016/j.bonr.2024.101735. eCollection 2024 Mar.
Cross-sectional size of a long bone shaft influences its mechanical properties. We recently used high-resolution peripheral quantitative computed tomography (HRpQCT) to create reference data for size measures of the radial and tibial diaphyses. However, data did not take into account the impact of bone length. Human bone exhibits relatively isometric allometry whereby cross-sectional area increases proportionally with bone length. The consequence is that taller than average individuals will generally have larger z-scores for bone size outcomes when length is not considered. The goal of the current work was to develop a means of determining whether an individual's cross-sectional bone size is suitable for their bone length. HRpQCT scans performed at 30 % of bone length proximal from the distal end of the radius and tibia were acquired from 1034 White females (age = 18.0 to 85.3 y) and 392 White males (age = 18.4 to 83.6 y). Positive relationships were confirmed between bone length and cross-sectional areas and estimated mechanical properties. Scaling factors were calculated and used to scale HRpQCT outcomes to bone length. Centile curves were generated for both raw and bone length scaled HRpQCT data using the LMS approach. Excel-based calculators are provided to facilitate calculation of z-scores for both raw and bone length scaled HRpQCT outcomes. The raw z-scores indicate the magnitude that an individual's HRpQCT outcomes differ relative to expected sex- and age-specific values, with the scaled z-scores also considering bone length. The latter enables it to be determined whether an individual or population of interest has normal sized bones for their length, which may have implications for injury risk. In addition to providing a means of expressing HRpQCT bone size outcomes relative to bone length, the current study also provides centile curves for outcomes previously without reference data, including tissue mineral density and moments of inertia.
长骨干的横截面尺寸会影响其力学性能。我们最近使用高分辨率外周定量计算机断层扫描（HRpQCT）来创建桡骨和胫骨干骺端尺寸测量的参考数据。然而，这些数据没有考虑骨长度的影响。人类骨骼呈现出相对等比的异速生长关系，即横截面积与骨长度成比例增加。其结果是，当不考虑长度时，高于平均身高的个体通常在骨尺寸结果方面会有更大的z分数。当前工作的目标是开发一种方法，以确定个体的横截面骨尺寸是否与其骨长度相匹配。从1034名白人女性（年龄18.0至85.3岁）和392名白人男性（年龄18.4至83.6岁）获取了在桡骨和胫骨远端近端骨长度30%处进行的HRpQCT扫描数据。证实了骨长度与横截面积以及估计的力学性能之间存在正相关关系。计算了缩放因子，并用于将HRpQCT结果缩放到骨长度。使用LMS方法为原始和经骨长度缩放的HRpQCT数据生成百分位数曲线。提供了基于Excel的计算器，以方便计算原始和经骨长度缩放的HRpQCT结果的z分数。原始z分数表示个体的HRpQCT结果相对于预期的性别和年龄特异性值的差异程度，而缩放后的z分数还考虑了骨长度。后者能够确定感兴趣的个体或群体的骨骼尺寸相对于其长度是否正常，这可能对受伤风险有影响。除了提供一种将HRpQCT骨尺寸结果相对于骨长度进行表达的方法外，本研究还为以前没有参考数据的结果提供了百分位数曲线，包括组织矿物质密度和惯性矩。
