Is cracking and popping of joints normal?
Cracking and popping of joints is usually normal and most of the time is nothing to be concerned about. Strangely enough the exact reason joints pop and snap is not totally understood. One theory is that the ligaments (tethers that hold the bones together) make these noises as they get tight rapidly when the joint is moving. In some instances, popping may be due to a tendon snapping over or around the joint. Another theory is that nitrogen bubbles in the fluid inside the joint are rapidly brought into or out of solution when the joint is manipulated, such as cracking the knuckles in the hand. These noises with movement of a joint, particularly the knee, may sound like folding stiff paper, and are called "crepitus". These noises are increased frequently after surgery on a joint, although the exact reason is not clear.
Do these sounds need to be treated?
Whatever the cause, these sounds do not need to be specifically treated. There are no long term sequelae of these noises, and they do not lead to future problems. There is no basis for the admonition to not crack your knuckles because it can lead to arthritis. There are no supplements or exercises to prevent these noises.
When should I worry about the cracking and popping of a joint?
The only time to worry about cracking or popping of a joint is if there is pain when the joint pops. Swelling is not normal and should be evaluated if it accompanies the noises. If the joint gets locked or stuck when it pops or cracks then it may indicate a joint problem that should be evaluated. If you are losing motion of the joint, if it is swelling or if you are losing function of the joint, then you should seek medical treatment.