The interplay between articular cartilage (AC) and subchondral bone (SB) plays a pivotal role in cartilage homeostasis and functionality. As direct connective pathways between the two are poorly understood, we examined the location-dependent characteristics of the 3D microchannel network within the SB that connects the basal cartilage layer to the bone marrow (i.e. cartilage-bone marrow microchannel connectors; CMMC). 43 measuring points were defined on five human cadaveric femoral heads with no signs of osteoarthritis (OA) (age ≤ 60), and cartilage-bone cylinders with diameters of 2.00 mm were extracted for high-resolution scanning (n = 215). The micro-CT data were categorized into three groups (load-bearing region: LBR, n = 60; non-load-bearing region: NLBR, n = 60; and the peripheral rim: PR, n = 95) based on a gait analysis estimation of the joint reaction force (young, healthy cohort with no signs of OA). At the AC-SB interface, the number of CMMC in the LBR was 1.8 times and 2.2 times higher compared to the NLBR, and the PR, respectively. On the other hand, the median Feret size of the CMMC were smallest in the LBR (55.2 µm) and increased in the NLBR (73.5 µm; p = 0.043) and the PR (89.1 µm; p = 0.043). AC thickness was positively associated with SB thickness (Pearson's r = 0.48; p < 1e-13), CMMC number. (r = 0.46; p < 1e-11), and circularity index (r = 0.61; p < 1e-38). In conclusion, our data suggest that regional differences in the microchannel architecture of SB might reflect regional differences in loading.

关节软骨 (AC) 和软骨下骨 (SB) 之间的相互作用在软骨稳态和功能中起着关键作用。由于对两者之间的直接连接途径知之甚少，我们检查了 SB 内连接基底软骨层和骨髓的 3D 微通道网络的位置依赖性特征（即软骨-骨髓微通道连接器；CMMC）。在五个没有骨关节炎（OA）迹象（年龄≤60）的人类尸体股骨头上定义了43个测量点，并提取了直径为2.00 mm的软骨骨圆柱体进行高分辨率扫描（n  = 215）。微 CT 数据分为三组（承重区域：LBR，n  = 60；非承重区域：NLBR，n = 60; 和外围边缘：PR，n  = 95）基于对关节反作用力的步态分析估计（年轻、健康的队列，没有 OA 的迹象）。在 AC-SB 接口处，LBR 中 CMMC 的数量分别是 NLBR 和 PR 的 1.8 倍和 2.2 倍。另一方面，CMMC 的中值 Feret 尺寸在 LBR (55.2 µm) 中最小，在 NLBR (73.5 µm; p  = 0.043) 和 PR (89.1 µm; p  = 0.043) 中增加。AC 厚度与 SB 厚度（Pearson 的r  = 0.48；p  < 1e-13）、CMMC 数呈正相关。( r  = 0.46; p  < 1e-11) 和圆度指数 ( r  = 0.61; p < 1e-38)。总之，我们的数据表明，SB 微通道结构的区域差异可能反映了负载的区域差异。