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A new paper gives us a better understanding of how articular joints are lubricated.
One of the most astonishing tribological systems in nature is that Found in our hips and other articular joints. These joints show exceedingly low sliding friction and contain their own lubricant-producing machinery. In most cases they last For many decades without significant wear.
Obviously there are good reasons For trying to understand how these remarkable tribosystems work, not least because our aging population is reaching the end oFthe useful IiFe oFtheir hip or knee joints in ever-increasing numbers.
Over the years there has been a multitude of different mechanisms invoked to describe the lubrication oF articular joints. These have included boundary lubrication, elastohydrodynamic lubrication, microelastohydrodynamic lubrication, squeeze-film lubrication, "weeping" lubrication, "boosted" lubrication, electrostatic lubrication, biphasic lubrication, brush lubrication and gel lubrication to name but a Few! In Fact, many oF these mechanisms may be involved to a greater or lesser extent, or in combination, under different conditions of joint use.
Nevertheless, it is clear that in many situations joints are operating from a standstill. Therefore, some...