类风湿关节炎软骨下骨水肿病变的骨三维结构研究

Three-dimensional bone structure of bone marrow edema lesion in rheumatoid arthritis

[目的]对类风湿关节炎(rheumatoid arthritis, RA)软骨下骨水肿病变(bone marrow edema, BME)区域开展三维结构及组织学研究,探讨骨髓水肿对骨结构强度的影响。[方法] 2016年1月~2018年5月,16例RA患者纳入本研究。TKA术前行MRI平扫,参照MRI图像术中取胫骨平台软骨下骨的骨髓水肿区域和非骨水肿区。骨标本使用微计算机断层扫描技术(Micro-CT)扫描及三维重建,测骨量以及骨小梁相关指标,制作组织切片,观察其组织学特点。[结果]与非骨水肿区相比,骨水肿区骨量的骨矿化密度、骨体积分数显著减少(P<0.05)。骨小梁结构的参数中,除骨小梁厚度无显著差异外(P>0.05),骨小梁间隔增大(P<0.05),骨小梁数目减少(P<0.05),骨小梁模式因子增大(P<0.05),结构模型指数增大(P<0.05)。组织学观察显示,骨水肿区域内大量的淋巴细胞浸润,并伴有新生血管及骨小梁结构破坏。[结论] RA的骨水肿区域存在活跃的炎症反应,骨量减少、骨小梁结构破坏,预示着局部骨力学强度的降低及后期的关节破坏。

[Objective] To investigate the 3-D structure changes of bone marrow edema(BME) region in rheumatoid arthritis(RA), and to explore the effect of bone marrow edema on the strength of bone structure. [Methods] From January 2016 to May 2018, 16 patients who were candidates of total knee arthroplasty(TKA) for RA were included into this study. Before TKA,MRI were taken to identify BME area in the subchondral bone of the tibial plateau. The samples in the BME area and non-BME area were obtained based on location in the preoperative MRI images from the bones removed during TKA. Micro-CT was used to scan and reconstruct the specimen. The region of interest was selected to detect bone mass and trabecular bone related parameters. Additionally, the histological features of the samples were observed by HE staining. [Results] In term of Micro CT analysis, the bone quantity related parameters, including bone mineral density(BMD) and bone volume fraction(BV/TV), were significantly decreased in the BME area compared with the non-BME area(P<0.05). In addition, the most trabecula structure related parameters in the BME area changed significantly compared with the non-BME area, trabecular separation(Tb.Sp), trabecular bone pattern factor(Tb.Pf) and structure model index(SMI) significantly increased(P<0.05), while trabecular number(Tb.N) significantly decreased(P<0.05) in the BME area, except no statistically significant difference in trabecula thickness(Th.Th) between the two areas. Regarding to histological observation. bone trabecular destruction accompanied with lymphocytes infiltration and angiogenesis was noticed in the BME region. [Conclusion] There are active inflammatory reactions in the BME region of RA accompanied with bone quantity decrease and trabecular structure destruction, which may lead to decrease of local bone strength and joint destruction in the following stage.