Furmann Denis, Nečas David, Rebenda David, Čípek Pavel, Vrbka Martin, Křupka Ivan, Hartl Martin
Faculty of Mechanical Engineering, Brno University of Technology, Brno 616 69, Czech Republic.
Materials (Basel). 2020 Mar 15;13(6):1334. doi: 10.3390/ma13061334.
Articular cartilage ensures smooth motion of natural synovial joints operating at very low friction. However, the number of patients suffering from joint diseases, usually associated with cartilage degradation, continuously increases. Therefore, an understanding of cartilage tribological behaviour is of great interest in order to minimize its degradation, preserving the reliable function of the joints. The aim of the present study is to provide a comprehensive comparison of frictional behaviour of articular cartilage, focusing on the effect of synovial fluid composition (i), speed (ii), and load (iii). The experiments were realized using a pin-on-plate tribometer with reciprocating motion. The articular cartilage pin was loaded against smooth glass plate while the tests consisted of loading and unloading phases in order to enable cartilage rehydration. Various model fluids containing albumin, γ-globulin, hyaluronic acid, and phospholipids were prepared in two different concentrations simulating physiologic and osteoarthritic synovial fluid. Two different speeds, 5 mm/s and 10 mm/s were applied, and the tests were carried out under 5 N and 10 N. It was found that protein-based solutions exhibit almost no difference in friction coefficient, independently of the concentration of the constituents. However, the behaviour is considerably changed when adding hyaluronic acid and phospholipids. Especially when interacting with γ-globulin, friction coefficient decreased substantially. In general, an important role of the interaction of fluid constituents was observed. On the other hand, a limited effect of speed was detected for most of the model fluids. Finally, it was shown that elevated load leads to lower friction, which corresponds well with previous observations. Further study should concentrate on specific explored phenomena focusing on the detailed statistical evaluation.
关节软骨可确保天然滑膜关节在极低摩擦下顺畅运动。然而，患有关节疾病（通常与软骨退化相关）的患者数量持续增加。因此，了解软骨的摩擦学行为对于尽量减少其退化、保持关节的可靠功能具有重要意义。本研究的目的是全面比较关节软骨的摩擦行为，重点关注滑液成分（i）、速度（ii）和负荷（iii）的影响。实验使用带有往复运动的销盘摩擦计来实现。将关节软骨销加载到光滑玻璃板上，同时测试包括加载和卸载阶段，以便使软骨再水化。制备了含有白蛋白、γ球蛋白、透明质酸和磷脂的各种模型流体，其浓度有两种，分别模拟生理和骨关节炎滑液。施加了5毫米/秒和10毫米/秒两种不同速度，并在5牛和10牛的力下进行测试。结果发现，基于蛋白质的溶液的摩擦系数几乎没有差异，与成分浓度无关。然而，添加透明质酸和磷脂后，情况有很大变化。特别是与γ球蛋白相互作用时，摩擦系数大幅下降。总体而言，观察到流体成分相互作用起到重要作用。另一方面，对于大多数模型流体，检测到速度的影响有限。最后，结果表明负荷增加会导致摩擦降低，这与先前的观察结果非常吻合。进一步的研究应集中在特定探索现象上，重点进行详细的统计评估。
