Pylios T, Shepherd D E T
Department of Bio-Medical Physics and Bio-Engineering, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, Scotland, UK.
J Biomech. 2004 Mar;37(3):405-11. doi: 10.1016/s0021-9290(03)00265-3.
The wrist joint is frequently affected by rheumatoid arthritis, resulting in wrist pain, deformity and ultimately loss of function. Artificial wrist implants have been introduced to treat the rheumatoid wrist, to attempt to alleviate pain and restore some function to the joint. The aim of this study was to predict the likely lubrication regimes that occur in wrist implants with spherical bearing surfaces. The implant was modelled as an equivalent ball-on-plane. Elastohydrodynamic lubrication theory was used to determine the minimum film thickness for the implant under different load, entraining velocity, lubricant viscosity, size of implant and material combinations. The results show that the highest film thickness is found in large implants, with high viscosity, high entraining velocity and low load. Hard-on-soft material combinations will operate with a boundary lubrication regime. Material combinations involving ceramic bearing surfaces have the potential to operate with a mixed lubrication regime.
腕关节经常受到类风湿性关节炎的影响，导致手腕疼痛、畸形，并最终丧失功能。人工腕关节植入物已被用于治疗类风湿性手腕，试图减轻疼痛并恢复关节的一些功能。本研究的目的是预测具有球形轴承表面的腕关节植入物中可能出现的润滑状态。该植入物被建模为等效的平面球模型。采用弹流润滑理论来确定植入物在不同载荷、牵引速度、润滑剂粘度、植入物尺寸和材料组合下的最小油膜厚度。结果表明，在大尺寸植入物中，油膜厚度最高，其具有高粘度、高牵引速度和低载荷。硬对软材料组合将在边界润滑状态下运行。涉及陶瓷轴承表面的材料组合有可能在混合润滑状态下运行。
