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.
Read on to find out the most common causes of knee pain; whatever the cause may be, it is of utmost importance to get a condition like persistent knee pain checked. 1. Bursitis. Inflammation of one or more small sacs (also called bursa) cushioning the area of friction between joints of the knees is called Bursitis. Each of the knees has 11 bursae. Bursa which lies over the kneecap or on patella of a knee gets aggravated and becomes the reason for swelling, also causing knee pain. The condition can cause extreme pain and even limit your mobility. Use of anti-inflammatory medications can treat bursitis. However, you should call your doctor right away if you notice fever in addition to swelling of your knee.