Activity may help you keep knee pain at bay

Want to avoid the debilitating knee pain? Keep moving, scientists suggest as they have found a mechanism that explains how motion can cause cartilage in the joints to reabsorb synovial fluid that leaks out in some conditions.

Synovial fluid that fills our joints plays the essential roles of supporting weight and lubricating joint surfaces. Loss of this fluid results in a gradual decrease in cartilage thickness and increase in friction, which is related to the degradation and joint pain of osteoarthritis.

Since cartilage is porous, fluid is readily squeezed out of the holes over time. Yet the symptoms associated with osteoarthritis usually take decades to develop. "The important question is why cartilage does not deflate over the course of days, months or years in our joints," said David Burris from University of Delaware. Burris and his colleagues have proposed a mechanism that explains how motion can cause cartilage to reabsorb liquid that leaks out.

"We know that cartilage thickness is maintained over decades in the joint and this is the first direct insight into why. It is activity itself that combats the natural deflation process associated with interstitial lubrication," he explained. Burris presented the findings at the AVS 62nd international symposium and exhibition held in San Jose, California, US.