Department of Orthopedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
Division of Systems Science and Informatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan.
Cartilage. 2021 Dec;13(2_suppl):1734S-1741S. doi: 10.1177/19476035211059597. Epub 2021 Nov 20.
Accurate analysis to quantify cartilage morphology is critical for evaluating degenerative conditions in osteoarthritis (OA). Three-dimensional (3D) optical scanning provides 3D data for the entire cartilage surface; however, there is no consensus on how to quantify it. Our purpose was to validate a 3D method for evaluating spatiotemporal alterations in degenerative cartilages in a rabbit OA model by analyzing their curvatures at various stages of progression.
Twelve rabbits underwent anterior cruciate ligament transection (ACLT) unilaterally and were divided into 4 groups: 4 weeks control, 4 weeks OA, 8 weeks control, and 8 weeks OA. 3D scanning, India ink staining, and histological assessments were performed in all groups. In 3D curvature visualization, the surfaces of the condyles were divided into 8 areas. The standard deviations (SD) of mean curvatures from all vertices of condylar surfaces and subareas were calculated.
Regarding the site of OA change, curvature analysis was consistent with India ink scoring. The SD of mean curvature correlated strongly with the India ink Osteoarthritis Research Society International (OARSI) score. In curvature histograms, the curvature distribution in OA was more scattered than in control. Of the 8 areas, significant OA progression in the posterolateral part of the lateral condyle (L-PL) was observed at 4 weeks. The histology result was consistent with the 3D evaluation in terms of representative section.
This study demonstrated that 3D scanning with curvature analysis can quantify the severity of cartilage degeneration objectively. Furthermore, the L-PL was found to be the initial area where OA degeneration occurred in the rabbit ACLT model.
准确分析软骨形态对于评估骨关节炎（OA）的退行性病变至关重要。三维（3D）光学扫描可提供整个软骨表面的 3D 数据，但对于如何对其进行量化尚无共识。我们的目的是通过分析兔 OA 模型中退行性软骨在不同进展阶段的曲率，验证一种用于评估其时空变化的 3D 方法。
12 只兔子行单侧前交叉韧带切断术（ACLT），并分为 4 组：4 周对照组、4 周 OA 组、8 周对照组和 8 周 OA 组。所有组均进行 3D 扫描、印度墨水染色和组织学评估。在 3D 曲率可视化中，将髁表面分为 8 个区域。计算了来自所有顶点的平均曲率的标准偏差（SD）。
就 OA 变化部位而言，曲率分析与印度墨水评分一致。平均曲率的 SD 与印度墨水骨关节炎研究协会国际评分（OARSI）强烈相关。在曲率直方图中，OA 组的曲率分布比对照组更分散。在 8 个区域中，外侧髁后外侧（L-PL）区域在 4 周时观察到明显的 OA 进展。组织学结果与 3D 评估在代表性切片上一致。
本研究表明，曲率分析的 3D 扫描可以客观地定量评估软骨退变的严重程度。此外，在兔 ACLT 模型中，发现 L-PL 是 OA 退变首先发生的区域。
