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.
Tenderness, swelling, and warmth in the joints are also common symptoms of knee arthritis. Some people feel a weakness in the knee joint or feel and hear cracking or clicking noises in addition to other OA symptoms.steoarthritis (OA) is a condition in which the cartilage between the bones wears down. Cartilage cushions your bones and helps you move your joints smoothly. Without enough cartilage, your bones rub together, causing pain, stiffness, and limited motion.