Department of Applied Physics, University of Eastern Finland, POB 1627, 70211, Kuopio, Finland.
Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
Ann Biomed Eng. 2019 Apr;47(4):953-966. doi: 10.1007/s10439-019-02213-4. Epub 2019 Jan 28.
Articular cartilage constituents (collagen, proteoglycans, fluid) are significantly altered during osteoarthritis (OA). A fibril-reinforced poroelastic (FRPE) material model can separate the contribution of each constituent on the mechanical response of cartilage. Yet, these properties and their OA related alterations are not known for human tibial cartilage. To answer this gap in the knowledge, we characterized the FRPE as well as elastic and viscoelastic properties of healthy and osteoarthritic human tibial cartilage. Tibial osteochondral explants (n = 27) harvested from 7 cadavers were mechanically tested in indentation followed by a quantification of elastic, viscoelastic and FRPE properties. Then they were histopathologically OARSI graded for the severity of OA. FRPE modeling revealed that non-fibrillar matrix modulus was higher in the healthy group compared to the early OA (p = 0.003) and advanced OA (p < 0.001) groups. The initial fibril network modulus was also higher in the healthy group compared to the early OA (p = 0.009) and advanced OA (p < 0.001) groups. The permeability correlated with the OARSI grade (p = 0.002, r = 0.56). For the first time, the FRPE properties were characterized for human tibial cartilage. This knowledge is crucial to improve the accuracy of computational knee joint models.
关节软骨成分（胶原、蛋白聚糖、液体）在骨关节炎（OA）中会发生显著改变。纤维增强多孔弹性（FRPE）材料模型可以将每个成分对软骨力学响应的贡献分开。然而，对于人类胫骨软骨，这些特性及其与 OA 相关的改变尚不清楚。为了解决这一知识空白，我们对健康和骨关节炎人类胫骨软骨的 FRPE 以及弹性和粘弹性特性进行了表征。从 7 具尸体中采集了胫骨骨软骨样本（n=27），并在压痕试验中对其进行了机械测试，随后对弹性、粘弹性和 FRPE 特性进行了量化。然后，根据 OA 的严重程度对其进行了 OARSI 组织病理学分级。FRPE 模型表明，与早期 OA（p=0.003）和晚期 OA（p<0.001）组相比，健康组的非纤维基质模量更高。与早期 OA（p=0.009）和晚期 OA（p<0.001）组相比，健康组的初始纤维网络模量也更高。渗透性与 OARSI 分级相关（p=0.002，r=0.56）。这是首次对人类胫骨软骨的 FRPE 特性进行了表征。这一知识对于提高计算膝关节模型的准确性至关重要。
