Finnilä Mikko A J, Thevenot Jérôme, Aho Olli-Matti, Tiitu Virpi, Rautiainen Jari, Kauppinen Sami, Nieminen Miika T, Pritzker Kenneth, Valkealahti Maarit, Lehenkari Petri, Saarakkala Simo
Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
J Orthop Res. 2017 Apr;35(4):785-792. doi: 10.1002/jor.23312. Epub 2016 Jun 22.
Despite increasing evidence that subchondral bone contributes to osteoarthritis (OA) pathogenesis, little is known about local changes in bone structure compared to cartilage degeneration. This study linked structural adaptation of subchondral bone with histological OA grade. Twenty-five osteochondral samples of macroscopically different degeneration were prepared from tibiae of 14 patients. Samples were scanned with micro-computed tomography (μCT) and both conventional structural parameters and novel 3D parameters based on local patterns were analyzed from the subchondral plate and trabecular bone. Subsequently, samples were processed for histology and evaluated for OARSI grade. Each bone parameter and OARSI grade was compared to assess structural adaptation of bone with OA severity. In addition, thicknesses of cartilage, calcified cartilage, and subchondral plate were analyzed from histological sections and compared with subchondral bone plate thickness from μCT. With increasing OARSI grade, the subchondral plate became thicker along with decreased specific bone surface, while there was no change in tissue mineral density. Histological analysis showed that subchondral plate thickness from μCT also includes calcified cartilage. Entropy of local patterns increased with OA severity, reflecting higher tissue heterogeneity. In the trabecular compartment, bone volume fraction and both trabecular thickness and number increased with OARSI grade while trabecular separation and structure model index decreased. Also, elevation of local patterns became longitudinal in the subchondral plate and axial transverse in trabecular bone with increasing OARSI grade. This study demonstrates the possibility of radiological assessment of OA severity by structural analysis of bone. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. J Orthop Res 35:785-792, 2017.
尽管越来越多的证据表明软骨下骨在骨关节炎（OA）发病机制中起作用，但与软骨退变相比，关于骨结构的局部变化却知之甚少。本研究将软骨下骨的结构适应性与组织学OA分级联系起来。从14例患者的胫骨制备了25个宏观退变程度不同的骨软骨样本。用微计算机断层扫描（μCT）对样本进行扫描，并分析软骨下板和松质骨的传统结构参数以及基于局部模式的新型三维参数。随后，对样本进行组织学处理并评估OARSI分级。比较每个骨参数和OARSI分级，以评估骨的结构适应性与OA严重程度的关系。此外，从组织学切片分析软骨、钙化软骨和软骨下板的厚度，并与μCT测量的软骨下骨板厚度进行比较。随着OARSI分级增加，软骨下板变厚，同时比骨表面积减小，而组织矿物质密度无变化。组织学分析表明，μCT测量的软骨下板厚度也包括钙化软骨。局部模式的熵随OA严重程度增加，反映出更高的组织异质性。在松质骨区域，骨体积分数、小梁厚度和数量随OARSI分级增加，而小梁间距和结构模型指数减小。而且，随着OARSI分级增加，局部模式的升高在软骨下板变为纵向，在松质骨变为轴向横向。本研究证明了通过骨结构分析对OA严重程度进行放射学评估的可能性。© 2016作者。《骨科研究杂志》由威利期刊公司出版。《骨科研究杂志》35:785 - 792，2017年。
