de Jong Joost J A, Willems Paul C, Arts Jacobus J, Bours Sandrine G P, Brink Peter R G, van Geel Tineke A C M, Poeze Martijn, Geusens Piet P, van Rietbergen Bert, van den Bergh Joop P W
Research School NUTRIM, Maastricht University, The Netherlands; Department of Rheumatology, Maastricht University Medical Center, The Netherlands.
Department of Orthopedics, Maastricht University Medical Center, The Netherlands; Research school CAPHRI, Maastricht University, The Netherlands.
Bone. 2014 Jul;64:65-74. doi: 10.1016/j.bone.2014.03.043. Epub 2014 Apr 2.
In clinical practice, fracture healing is evaluated by clinical judgment in combination with conventional radiography. Due to limited resolution, radiographs don't provide detailed information regarding the bone micro-architecture and bone strength. Recently, assessment of in vivo bone density, architectural and mechanical properties at the microscale became possible using high resolution peripheral quantitative computed tomography (HR-pQCT) in combination with micro finite element analysis (μFEA). So far, such techniques have been used mainly to study intact bone. The aim of this study was to explore whether these techniques can also be used to assess changes in bone density, micro-architecture and bone stiffness during fracture healing. Therefore, the fracture region in eighteen women, aged 50 years or older with a stable distal radius fracture, was scanned using HR-pQCT at 1-2 (baseline), 3-4, 6-8 and 12weeks post-fracture. At 1-2 and 12 weeks post-fracture the distal radius at the contra-lateral side was also scanned as control. Standard bone density, micro-architectural and geometric parameters were calculated and bone stiffness in compression, torsion and bending was assessed using μFEA. A linear mixed effect model with time post-fracture as fixed effect was used to detect significant (p-value ≤0.05) changes from baseline. Wrist pain and function were scored using the patient-rated wrist evaluation (PRWE) questionnaire. Correlations between the bone parameters and the PRWE score were calculated by Spearman's correlation coefficient. At the fracture site, total and trabecular bone density increased by 11% and 20%, respectively, at 6-8 weeks, whereas cortical density was decreased by 4%. Trabecular thickness increased by 23-31% at 6-8 and 12 weeks and the intertrabecular area became blurred, indicating intertrabecular bone formation. Compared to baseline, calculated bone stiffness in compression, torsion and bending was increased by 31% after 12 weeks. A moderate negative correlation was found between the stiffness and the PRWE score. No changes were observed at the contra-lateral side. The results demonstrate that it is feasible to assess clinically relevant and significant longitudinal changes in bone density, micro-architecture and mechanical properties at the fracture region during the healing process of stable distal radius fractures using HR-pQCT.
在临床实践中，骨折愈合通过临床判断结合传统X线摄影进行评估。由于分辨率有限，X线片无法提供有关骨微结构和骨强度的详细信息。最近，使用高分辨率外周定量计算机断层扫描（HR-pQCT）结合微有限元分析（μFEA），在体内评估微观尺度下的骨密度、结构和力学性能成为可能。到目前为止，这些技术主要用于研究完整的骨骼。本研究的目的是探讨这些技术是否也可用于评估骨折愈合过程中骨密度、微结构和骨刚度的变化。因此，对18名年龄在50岁及以上、患有稳定型桡骨远端骨折的女性，在骨折后1 - 2周（基线）、3 - 4周、6 - 8周和12周使用HR-pQCT对骨折区域进行扫描。在骨折后1 - 2周和12周，还对另一侧的桡骨远端进行扫描作为对照。计算标准骨密度、微结构和几何参数，并使用μFEA评估压缩、扭转和弯曲时的骨刚度。以骨折后时间为固定效应的线性混合效应模型用于检测与基线相比的显著（p值≤0.05）变化。使用患者自评手腕评估（PRWE）问卷对腕部疼痛和功能进行评分。通过Spearman相关系数计算骨参数与PRWE评分之间的相关性。在骨折部位，6 - 8周时，总体骨密度和小梁骨密度分别增加了11%和20%，而皮质骨密度下降了4%。6 - 8周和12周时，小梁厚度增加了23 - 31%，小梁间面积变得模糊，表明小梁间有骨形成。与基线相比，12周后计算得出的压缩、扭转和弯曲时的骨刚度增加了31%。在刚度与PRWE评分之间发现了中度负相关。在对侧未观察到变化。结果表明，使用HR-pQCT评估稳定型桡骨远端骨折愈合过程中骨折区域骨密度、微结构和力学性能的临床相关且显著的纵向变化是可行的。
