Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.
Department of Bioengineering, University of California, San Francisco and University of California, Berkeley Joint Graduate Group in Bioengineering, San Francisco, California, USA.
J Orthop Res. 2021 Jun;39(6):1305-1317. doi: 10.1002/jor.24849. Epub 2020 Oct 13.
Many studies have validated cartilage thickness as a biomarker for knee osteoarthritis (OA); however, few studies investigate beyond cross-sectional observations or comparisons across two timepoints. By characterizing the trajectory of cartilage thickness changes over 8 years in healthy individuals from the OA initiative data set, this study discovers associations between the dynamics of cartilage changes and OA incidence. A fully automated cartilage segmentation and thickness measurement method were developed and validated against manual measurements: mean absolute error = 0.11-0.14 mm (n = 4129 knees) and automatic reproducibility = 0.04-0.07 mm (n = 316 knees). The mean thickness for the medial and lateral tibia (MT, LT), central weight-bearing medial and lateral femur (cMF, cLF), and patella (P) cartilage compartments were quantified for 1453 knees at seven timepoints. Trajectory subgroups were defined per cartilage compartment such as stable, thinning to thickening, accelerated thickening, plateaued thickening, thickening to thinning, accelerated thinning, or plateaued thinning. For tibiofemoral compartments, the stable (22%-36%) and plateaued thinning (22%-37%) trajectories were the most common, with an average initial velocity (μm/month), acceleration (μm/month ) for the plateaued thinning trajectories LT: -2.66, 0.0326; MT: -2.49, 0.0365; cMF: -3.51, 0.0509; and cLF: -2.68, 0.041. In the patella compartment, the plateaued thinning (35%) and thickening to thinning (24%) trajectories were the most common, with an average initial velocity, acceleration for each -4.17, 0.0424; 1.95, -0.0835. Knees with nonstable trajectories had higher adjusted odds of OA incidence than stable trajectories: accelerated thickening, accelerated thinning, and plateaued thinning trajectories of the MT had adjusted odds ratio (OR) of 18.9, 5.48, and 1.47, respectively; in the cMF, adjusted OR of 8.55, 10.1, and 2.61, respectively.
许多研究已经验证了软骨厚度作为膝关节骨关节炎（OA）的生物标志物；然而，很少有研究在横断面观察或两个时间点之间的比较之外进行研究。通过对 OA 倡议数据集的健康个体的软骨厚度变化轨迹进行 8 年的特征描述，本研究发现了软骨变化动态与 OA 发病率之间的关联。开发了一种全自动的软骨分割和厚度测量方法，并通过手动测量进行了验证：平均绝对误差=0.11-0.14mm（n=4129 个膝关节）和自动可重复性=0.04-0.07mm（n=316 个膝关节）。在 7 个时间点测量了 1453 个膝关节的内侧胫骨（MT）、外侧胫骨（LT）、中央负重股骨的内侧和外侧（cMF、cLF）和髌骨（P）软骨间隙的平均厚度。根据每个软骨间隙定义了轨迹亚组，例如稳定、变薄到变厚、加速变厚、平台变厚、变厚到变薄、加速变薄或平台变薄。对于胫股关节间隙，稳定（22%-36%）和平台变薄（22%-37%）轨迹最常见，平均初始速度（μm/月）、平台变薄轨迹的加速度（μm/月）为 LT：-2.66，0.0326；MT：-2.49，0.0365；cMF：-3.51，0.0509；和 cLF：-2.68，0.041。在髌骨间隙中，平台变薄（35%）和变厚到变薄（24%）轨迹最常见，平均初始速度、加速度分别为-4.17，0.0424；1.95，-0.0835。非稳定轨迹的膝关节发生 OA 的调整后比值比（OR）高于稳定轨迹：MT 的加速变厚、加速变薄和平台变薄轨迹的调整 OR 分别为 18.9、5.48 和 1.47；在 cMF 中，调整后的 OR 分别为 8.55、10.1 和 2.61。
