Department of Orthopedic Surgery, Regional University Hospital of Málaga, Spain.
Department of Radiology, Massachusetts General Hospital, Charlestown, USA; Department of Dental Surgery, Faculty of Dental Surgery, University of Malta.
Bone. 2020 Nov;140:115558. doi: 10.1016/j.bone.2020.115558. Epub 2020 Jul 27.
Bone strength depends on multiple factors such as bone density, architecture and composition turnover. However, the role these factors play in osteoporotic fractures is not well understood.
The aim of this study was to analyze trabecular bone architecture, and its crystal and organic composition in humans, by comparing samples taken from patients who had a hip fracture (HF) and individuals with hip osteoarthritis (HOA).
The study included 31 HF patients and 42 cases of HOA who underwent joint replacement surgery between 1/1/2013 and 31/12/2013. Trabecular bone samples were collected from the femoral heads and analyzed using a dual-energy X-ray absorptiometry, micro-CT, and solid-state high-resolution magic-angle-spinning nuclear magnetic resonance (MAS-NMR) spectroscopy.
No differences in proton or phosphorus concentration were found between the two groups using H single pulse, P single pulse, P single pulse with proton decoupling NMR spectroscopy, in hydroxyapatite (HA) c-axis or a-axis crystal length. Bone volume fraction (BV/TV), trabecular number (Tb.N), and bone mineral density (BMD) were higher in the HO group than in the HF group [28.6% ± 10.5 vs 20.3% ± 6.6 (p = 0.026); 2.58 mm ± 1.57 vs 1.5 mm ± 0.79 (p = 0.005); and 0.39 g/cm ± 0.10 vs. 0.28 g/cm ± 0.05 (p = 0.002), respectively]. The trabecular separation (Tp.Sp) was lower in the HO group 0.42 mm ± 0.23 compared with the HF group 0.58 mm ± 0.27 (p = 0.036). In the HO group, BMD was correlated with BV/TV (r = 0.704, p < 0.001), BMC (r = 0.853, p < 0.001), Tb.N (r = 0.653, p < 0.001), Tb.Sp (-0.561, p < 0.001) and H concentration (-0.580, p < 0.001) in the HO group. BMD was not correlated with BV/TV, Tb.Sp, Tb.Th, Tb.N, Tb.PF, H concentration or HA crystal size in the HF group.
Patients with HO who did not sustain previous hip fractures had a higher femoral head BMD, BV/TV, and Tb.N than HF patients. In HO patients, BMD was positively correlated with the BV/TV and Tb.N and negatively correlated with the femoral head organic content and trabecular separation. Interestingly, these correlations were not found in HF patients with relatively lower bone densities. Therefore, osteoporotic patients with similar low bone densities could have significant microstructural differences. No differences were found between the two groups at a HA crystal level.
骨骼强度取决于多种因素，如骨密度、结构和组成周转率。然而，这些因素在骨质疏松性骨折中的作用尚不清楚。
本研究旨在通过比较髋部骨折（HF）患者和髋部骨关节炎（HOA）患者的样本，分析人类的小梁骨结构及其晶体和有机组成。
该研究纳入了 31 例 HF 患者和 42 例接受关节置换手术的 HOA 患者，研究时间为 2013 年 1 月 1 日至 12 月 31 日。从股骨头采集小梁骨样本，并使用双能 X 射线吸收法、微 CT 和固态高分辨率魔角旋转核磁共振（MAS-NMR）光谱进行分析。
使用 H 单脉冲、P 单脉冲、P 单脉冲结合质子去耦 NMR 光谱法，在羟基磷灰石（HA）c 轴或 a 轴晶体长度方面，两组患者的质子或磷浓度无差异。HO 组的骨体积分数（BV/TV）、小梁数（Tb.N）和骨密度（BMD）均高于 HF 组[28.6%±10.5%比 20.3%±6.6%（p=0.026）；2.58mm±1.57mm 比 1.5mm±0.79mm（p=0.005）；0.39g/cm±0.10g/cm 比 0.28g/cm±0.05g/cm（p=0.002）]。HO 组的小梁分离度（Tp.Sp）也低于 HF 组，为 0.42mm±0.23mm 比 0.58mm±0.27mm（p=0.036）。在 HO 组中，BMD 与 BV/TV（r=0.704，p<0.001）、BMC（r=0.853，p<0.001）、Tb.N（r=0.653，p<0.001）、Tb.Sp（-0.561，p<0.001）和 H 浓度（-0.580，p<0.001）呈正相关。在 HF 组中，BMD 与 BV/TV、Tb.Sp、Tb.Th、Tb.N、Tb.PF、H 浓度或 HA 晶体尺寸均无相关性。
未发生过髋部骨折的 HOA 患者的股骨头 BMD、BV/TV 和 Tb.N 均高于 HF 患者。在 HOA 患者中，BMD 与 BV/TV 和 Tb.N 呈正相关，与股骨头有机含量和小梁分离度呈负相关。有趣的是，在骨密度相对较低的 HF 患者中，并未发现这些相关性。因此，具有相似低骨密度的骨质疏松症患者可能存在显著的微观结构差异。两组患者在 HA 晶体水平无差异。
