BACKGROUND Osteoarthritis is a common, localized joint disease that causes pain, stiffness and reduced mobility. The effects of osteoarthritis on the extensional rheology of synovial fluid in the knees are not fully understood and consequently require further study. OBJECTIVE The purpose of this work is to study the extensional rheology of osteoarthritic synovial fluid and to investigate a possible correlation between synovial fluid protein concentration and extensional rheology. The study will also investigate possible correlations with the shear rheology. METHODS 21 osteoarthritic synovial fluid samples were studied under extensional flow with a capillary breakup extensional rheometer. Extensional rheological properties were correlated with protein concentration and with shear rheological properties measured in a prior study. Viscosupplement was also studied under extensional flow for comparison. RESULTS Extensional rheological properties were found to vary widely between samples, but in general were found to agree with previous studies. No statistically significant correlation was identified between extensional rheological properties and protein concentration. Positive correlations were identified between zero shear viscosity and terminal extensional viscosity (R-squared = 0.73), zero shear viscosity and extensional relaxation time (R-squared = 0.84), and shear relaxation time and extensional relaxation time (R-squared = 0.75). CONCLUSIONS Appropriate CaBER operating parameters for study of osteoarthritic synovial fluid were identified. No statistically significant correlation was found to exist between protein concentration and extensional rheological parameters. Positive correlations were identified between several shear and extensional rheological parameters. The reported values for extensional viscosity and relaxation times for synovial fluid were found to be within one order of magnitude with a recent study of post mortem synovial fluid.

中文翻译：

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骨关节炎滑液及其与蛋白质浓度的关系。

背景技术骨关节炎是一种常见的局部关节疾病，其引起疼痛，僵硬和活动能力降低。骨关节炎对膝关节滑液延伸流变性的影响尚未完全了解，因此需要进一步研究。目的这项工作的目的是研究骨关节炎滑液的拉伸流变学，并研究滑液蛋白浓度与拉伸流变学之间的可能关系。该研究还将研究与剪切流变学的可能相关性。方法采用毛细管破裂伸张流变仪在伸张流下研究21例骨关节炎滑液样品。拉伸流变学性质与蛋白质浓度和先前研究中测得的剪切流变学性质相关。还研究了在扩展流动下的粘稠度补充。结果发现样品之间的拉伸流变特性差异很大，但总体上与以前的研究一致。在延伸流变特性和蛋白质浓度之间未发现统计学上的显着相关性。在零剪切粘度和末端延伸粘度（R平方= 0.73），零剪切粘度和延伸松弛时间（R平方= 0.84）以及剪切松弛时间和延伸松弛时间（R平方= 0.75）之间确定了正相关。 。结论确定了适合研究骨关节炎滑液的CaBER操作参数。没有发现蛋白质浓度和延伸流变学参数之间存在统计学上的显着相关性。在几个剪切流变参数和拉伸流变参数之间确定了正相关。据验尸滑液的最新研究发现，滑液的拉伸粘度和松弛时间的报告值在一个数量级之内。