Primo Boost Keto Most often, the so-called crunch in the knees appears when the joints start to move and small gas bubbles burst. By the way, sometimes crepitus appears due to the loss of elasticity of cartilage – tissue rub against each other, causing a crunch. Is it possible to improve the situation and take measures against crunch in the knees, without resorting to the services of physicians? Exercises to help remove the crunch in the knees.