Popping
You may experience a popping sound within your knee joint when a meniscus tear occurs. You may feel pain afterwards, particularly when the area is touched. [6]
The “pop” sound is often the sound of tearing ligaments or breaking cartilage. Catching and popping can also be caused by tiny pieces of broken cartilage floating loose within the knee joint. This pop is typically an audible pop sound.
The sound and discomfort may be a mechanical effect, which feels like something is stuck in the knee when it goes back backwards and forwards. When you flex your knee or straighten them, when you climb a flight of stairs, or when you walk around, you can hear occasional pops, clicks, and crackles in your knees.