Tribology Laboratory, School of Mechanical and Chemical Engineering, University of Western Australia, Crawley, WA 6009, Australia.
J Orthop Res. 2011 Aug;29(8):1161-7. doi: 10.1002/jor.21396. Epub 2011 Mar 4.
The objective of this work is to evaluate differences in trabecular bone (TB) texture between subjects with and without tibiofemoral cartilage defects using a variance orientation transform (VOT) method. A case-control study was performed in subjects without radiographic knee osteoarthritis (OA) (K&L grade <2) matched on sex, BMI, age, knee compartment, and meniscectomy where cases (n = 28) had cartilage defects (grade ≥2) and controls (n = 28) had no cartilage defects (grade <2). Cartilage defects were assessed from MRI using validated methods. The VOT was applied to TB regions selected on medial and lateral compartments in knee X-rays and fractal signatures (FS) in the horizontal (FS(H) ) and vertical (FS(V) ) directions, and along the roughest part of TB (FS(Sta) ) and texture aspect ratio signatures (StrS), at different trabecular image sizes (0.30-0.70 mm) were calculated. Compared with controls, FS(V) for cases were higher (p < 0.011) at image sizes 0.30-0.40 mm and 0.45-0.55 mm in the medial compartment. In the lateral compartment, FS(H) and FS(Sta) for cases were higher (p < 0.028) than those for controls at 0.30-0.40 mm and 0.45-0.55 mm, while FS(V) was higher (p < 0.02) at 0.30-0.40 mm. TB texture roughness was greater in subjects with cartilage defects than in subjects without, suggesting thinning and fenestration of TB occur early in OA and that the VOT identifies changes in TB in knees with early cartilage damage. No differences in StrS (p > 0.05) were found.
本研究旨在采用变分取向变换（VOT）方法，评估伴有和不伴有胫股软骨缺损的受试者之间小梁骨（TB）纹理的差异。本研究为病例对照研究，纳入了膝关节无放射学骨关节炎（OA）（K&L 分级<2）的受试者，按性别、BMI、年龄、膝关节间隙和半月板切除术进行匹配，其中病例（n=28）有软骨缺损（分级≥2），对照组（n=28）无软骨缺损（分级<2）。使用验证方法从 MRI 评估软骨缺损。在膝关节 X 线片的内侧和外侧间隙选择 TB 区域应用 VOT，并在水平（FS(H)）和垂直（FS(V)）方向以及 TB 最粗糙部分（FS(Sta)）计算分形特征（FS）和纹理纵横比特征（StrS），并在不同的小梁图像大小（0.30-0.70mm）下计算。与对照组相比，病例组在图像大小为 0.30-0.40mm 和 0.45-0.55mm 时，FS(V)更高（p<0.011）。在外侧间隙中，病例组的 FS(H)和 FS(Sta)在 0.30-0.40mm 和 0.45-0.55mm 时高于对照组（p<0.028），而 FS(V)在 0.30-0.40mm 时更高（p<0.02）。与无软骨缺损的受试者相比，有软骨缺损的受试者的 TB 纹理粗糙度更大，这表明 TB 的变薄和窗孔形成发生在 OA 的早期，并且 VOT 可以识别早期软骨损伤膝关节中 TB 的变化。StrS 无差异（p>0.05）。
