Yao J Q, Unsworth A
School of Engineering and Computer Science, University of Durham.
Proc Inst Mech Eng H. 1993;207(4):245-54. doi: 10.1243/PIME_PROC_1993_207_303_02.
The asperity lubrication in human joints is examined in the present paper, with particular reference to the tertiary undulation with wavelengths of around 20-45 microns. It was found that, under dynamic physiological loading conditions, the secondary waviness of the cartilaginous surface (typically 0.5 mm wavelength) could be effectively flattened to sustain a fluid film of 0.1-0.3 micron thick, while the tertiary waviness could be squashed to sustain a much thinner fluid film of 0.01 micron (10 nm) thick with normal synovial fluid as the lubricant. The calculated film thickness for the tertiary undulation was less than 5 nm when the ankle joint was lubricated by Ringer's solution or pathological synovial fluids, or when only quasi-static loading conditions were considered, while a sufficiently thick fluid film could still be formed when the secondary undulations were considered alone. It was thus suggested that the fluid film lubrication mechanism was operative for human joints with normal synovial fluid as the lubricant under physiological dynamic loading conditions and the mixed lubrication mechanism could take over when static loading conditions prevailed or when watery lubricants (eta approximately 0.001 Pa s) were used.
本文研究了人体关节中的粗糙度润滑，特别关注波长约为20 - 45微米的三级起伏。研究发现，在动态生理负荷条件下，软骨表面的二级波纹（典型波长为0.5毫米）可有效变平，以维持0.1 - 0.3微米厚的液膜，而三级波纹可被挤压，以正常滑液为润滑剂维持仅0.01微米（10纳米）厚的更薄液膜。当踝关节用林格氏液或病理性滑液润滑时，或仅考虑准静态负荷条件时，三级起伏的计算膜厚小于5纳米，而仅考虑二级起伏时仍可形成足够厚的液膜。因此表明，在生理动态负荷条件下，以正常滑液为润滑剂时，人体关节的液膜润滑机制起作用，而在静态负荷条件占主导或使用水性润滑剂（粘度约为0.001帕·秒）时，混合润滑机制可能起主导作用。
