1727, from Japanese samurai warrior, knight, originally the military retainer of the daimio, variant of saburai, nominal form of sabura(h)u to be in attendance, to serve..
The bubbles make a noise when they burst. This is called cavitation. Another cause for painless popping in the knee is when the ligaments and tendons catch as they go over a bony lump and pop when they snap back into place. Or the clicking and popping may be caused by catching on soft tissue or scar tissue within the knee.
Chondromalacia patella is when there is softening and damage to the cartilage on the back of the patella (kneecap). Here we will look at the most common causes and symptoms of chondromalacia as well as the best ways to treat it and the recovery process. Chondromalacia patella caused front knee pain, swelling and clicking/grinding noises when moving the knee.