A New Stress Test for Knee Joint Cartilage
A New Stress Test for Knee Joint Cartilage
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DOI：
10.1038/s41598-018-38104-2
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发表时间：
2019-02-19
影响因子：
4.6
通讯作者：
DeFrate, Louis E.
中科院分区：
文献类型：
--
作者：
Paranjape, Chinmay S.;Cutcliffe, Hattie C.;DeFrate, Louis E.
软骨的新陈代谢--包括软骨成分和结构的合成和分解--受其机械负荷的影响。因此，经常建议进行体力活动以保持软骨健康，并治疗或减缓骨关节炎的进展，骨关节炎是一种导致软骨退化的衰弱关节疾病。然而，还不能规定适当的运动频率、强度和持续时间，因为还没有对运动后的软骨进行直接的体内评估。为了解决这一认识上的差距，我们开发了一种软骨应力测试来测量健康受试者胫骨软骨对步行运动的体内应变反应。我们以剂量依赖的方式改变行走时间和速度，以量化这些变量如何影响软骨应变。我们发现行走时间与体内压缩应变之间存在非线性关系，随着行走时间的增加，压缩应变开始增加，然后随着行走时间的延长而趋于平稳。这项工作提供了行走过程中软骨蠕变行为的创新测量(这在体外已经有很好的记录，但在体内还没有)。本研究表明，在本研究测试的速度范围内(0.9-2.0m/S)，压应变随步行速度的增加而增加。此外，我们的数据提供了胫骨软骨对不同剂量的步行作为机械刺激的体内应变响应的新测量，步行60分钟后观察到的最大应变为5.0%。这些数据描述了行走过程中健康关节软骨行为的生理基准，并为研究运动对软骨健康的影响提供了亟需的基线。
Cartilage metabolism-both the synthesis and breakdown of cartilage constituents and architecture-is influenced by its mechanical loading. Therefore, physical activity is often recommended to maintain cartilage health and to treat or slow the progression of osteoarthritis, a debilitating joint disease causing cartilage degeneration. However, the appropriate exercise frequency, intensity, and duration cannot be prescribed because direct in vivo evaluation of cartilage following exercise has not yet been performed. To address this gap in knowledge, we developed a cartilage stress test to measure the in vivo strain response of healthy human subjects' tibial cartilage to walking exercise. We varied both walk duration and speed in a dose-dependent manner to quantify how these variables affect cartilage strain. We found a nonlinear relationship between walk duration and in vivo compressive strain, with compressive strain initially increasing with increasing duration, then leveling off with longer durations. This work provides innovative measurements of cartilage creep behavior (which has been well-documented in vitro but not in vivo) during walking. This study showed that compressive strain increased with increasing walking speed for the speeds tested in this study (0.9-2.0 m/s). Furthermore, our data provide novel measurements of the in vivo strain response of tibial cartilage to various doses of walking as a mechanical stimulus, with maximal strains of 5.0% observed after 60 minutes of walking. These data describe physiological benchmarks for healthy articular cartilage behavior during walking and provide a much-needed baseline for studies investigating the effect of exercise on cartilage health.