Relationships between composition, structure and constituent-specific functional properties of human articular cartilage at different stages of osteoarthritis (OA) are poorly known. We established these relationships by comparison of elastic, viscoelastic and fibril-reinforced poroelastic mechanical properties with microscopic and spectroscopic analysis of structure and composition of healthy and osteoarthritic human tibial cartilage (n = 27). At a low frequency (0.005 Hz), proteoglycan content correlated negatively and collagen content correlated positively with the phase difference (i.e. tissue viscosity). At a high-frequency regime (> 0.05 Hz), proteoglycan content correlated negatively and collagen orientation angle correlated positively with the phase difference. Proteoglycans were lost in the early and advanced OA groups compared to the healthy group, while the superficial collagen orientation angle was greater only in the advanced OA group compared to the healthy group. Simultaneously, the initial fibril network modulus (fibril pretension) was smaller in the early and advanced OA groups compared to the healthy group. These findings suggest different mechanisms contribute to cartilage viscosity in low and high frequencies, and that the loss of superficial collagen pretension during early OA is due to lower tissue swelling (PG loss), while in advanced OA, both collagen disorganization and lower swelling modulate the collagen fibril pretension.

人类关节软骨在骨关节炎 (OA) 不同阶段的组成、结构和成分特异性功能特性之间的关系知之甚少。我们通过比较弹性、粘弹性和原纤维增强的多孔弹性力学性能与健康和骨关节炎人类胫骨软骨的结构和组成的显微和光谱分析来建立这些关系（n = 27）。在低频 (0.005 Hz) 下，蛋白多糖含量与相位差（即组织粘度）呈负相关，而胶原含量呈正相关。在高频状态 (> 0.05 Hz) 下，蛋白多糖含量呈负相关，胶原取向角与相位差呈正相关。与健康组相比，早期和晚期 OA 组的蛋白多糖丢失，而与健康组相比，仅晚期 OA 组的表面胶原定向角更大。同时，与健康组相比，早期和晚期 OA 组的初始原纤维网络模量（原纤维预张力）更小。这些发现表明不同的机制有助于低频和高频的软骨粘度，