Quantitative Multinuclear Musculoskeletal Imaging Group, Center for Biomedical Imaging, NYU Langone Medical Center, 660 First Avenue, 2nd Floor, New York, NY 10016, USA.
Osteoporos Int. 2013 Apr;24(4):1407-17. doi: 10.1007/s00198-012-2105-8. Epub 2012 Aug 15.
Micro-finite element analysis applied to high-resolution (0.234-mm length scale) MRI reveals greater whole and cancellous bone stiffness, but not greater cortical bone stiffness, in the distal femur of female dancers compared to controls. Greater whole bone stiffness appears to be mediated by cancellous, rather than cortical bone adaptation.
The purpose of this study was to compare bone mechanical competence (stiffness) in the distal femur of female dancers compared to healthy, relatively inactive female controls.
This study had institutional review board approval. We recruited nine female modern dancers (25.7±5.8 years, 1.63±0.06 m, 57.1±4.6 kg) and ten relatively inactive, healthy female controls matched for age, height, and weight (32.1±4.8 years, 1.6±0.04 m, 55.8±5.9 kg). We scanned the distal femur using a 7-T MRI scanner and a three-dimensional fast low-angle shot sequence (TR/TE=31 ms/5.1 ms, 0.234 mm×0.234 mm×1 mm, 80 slices). We applied micro-finite element analysis to 10-mm-thick volumes of interest at the distal femoral diaphysis, metaphysis, and epiphysis to compute stiffness and cross-sectional area of whole, cortical, and cancellous bone, as well as cortical thickness. We applied two-tailed t-tests and ANCOVA to compare groups.
Dancers demonstrated greater whole and cancellous bone stiffness and cross-sectional area at all locations (p<0.05). Cortical bone stiffness, cross-sectional area, and thickness did not differ between groups (>0.08). At all locations, the percent of intact whole bone stiffness for cortical bone alone was lower in dancers (p<0.05). Adjustment for cancellous bone cross-sectional area eliminated significant differences in whole bone stiffness between groups (p>0.07), but adjustment for cortical bone cross-sectional area did not (p<0.03).
Modern dancers have greater whole and cancellous bone stiffness in the distal femur compared to controls. Elevated whole bone stiffness in dancers may be mediated via cancellous, rather than cortical bone adaptation.
应用于高分辨率（0.234 毫米尺度）MRI 的微有限元分析显示，与对照组相比，女性舞者的远端股骨的整体和松质骨刚度更大，但皮质骨刚度没有更大。整体骨刚度的增加似乎是由松质骨而不是皮质骨适应介导的。
本研究的目的是比较女性舞者与健康、相对不活跃的女性对照组相比，远端股骨的骨力学能力（刚度）。
本研究获得了机构审查委员会的批准。我们招募了 9 名女性现代舞者（25.7±5.8 岁，1.63±0.06 m，57.1±4.6 kg）和 10 名年龄、身高和体重相匹配的相对不活跃、健康的女性对照组（32.1±4.8 岁，1.6±0.04 m，55.8±5.9 kg）。我们使用 7-T MRI 扫描仪和三维快速低角度拍摄序列（TR/TE=31 ms/5.1 ms，0.234 mm×0.234 mm×1 mm，80 片）对远端股骨进行扫描。我们将微有限元分析应用于远端股骨骨干、干骺端和骨骺的 10 毫米厚的感兴趣体积，以计算整体、皮质和松质骨的刚度和横截面积，以及皮质厚度。我们应用双侧 t 检验和协方差分析来比较组间差异。
舞者在所有部位的整体和松质骨刚度和横截面积均较大（p<0.05）。皮质骨刚度、横截面积和厚度在组间无差异（>0.08）。在所有部位，仅皮质骨的完整整体骨刚度的百分比在舞者中较低（p<0.05）。调整松质骨横截面积后，组间整体骨刚度的差异消除（p>0.07），但调整皮质骨横截面积后差异仍存在（p<0.03）。
与对照组相比，现代舞者的远端股骨整体和松质骨刚度更大。舞者整体骨刚度的升高可能是通过松质骨而不是皮质骨适应介导的。
