What Causes Popping Joints?

What causes them and when to see a doctor

An elderly woman suffering from joint pain.
Jose Luis Pelaez/Getty Images

Most of us will have had an experience when we are walking, squatting, or ascending stairs and our knee suddenly "pops." The same might happen when you are reaching for something on a shelf and your elbow or shoulder joint makes a popping sound.

While joint popping rarely causes any pain, it can be unsettling, especially if it occurs frequently or is especially loud. Should something like this be considered normal, or it could it be a sign a problem that needs looking at?

Causes of Popping Joints

Popping joints can happen for any number of reasons. They are usually not problematic, especially if there is no pain or impairment of movement. But, in some cases, popping can occur as part of a degenerative disorder that makes the joint susceptible to these and other sounds.

Among some of the more common explanations:

  • Popping can occur when bubbles (cavitations) form in joints as they are pulled apart. When knuckles are cracked, for example, the nitrogen bubbles inside the synovial (joint) fluid can suddenly escape and cause an audible popping.
  • Joint surfaces can become increasingly rough due to cartilage loss and the development of osteophytes (bone spurs) associated with osteoarthritis.
  • Ligaments (fibrous tissues that connect two bones at a joint) can be tight and pop when they are suddenly or abnormally moved. This can sometimes cause a jolt of pain or nothing at all. At other time, the sound may be related to the actual tearing of a ligament.
  • After a joint injury or surgery, ligaments can form scar tissue known as adhesions which are prone to popping and cracking.
  • Tendons (fibrous tissues that connect muscles to bone) can also make popping noises as they snap around a joint. We see this commonly with a condition known as snapping hip syndrome (also known as dancer's hip).

Popping can occur in any joint of the body. Flexing or rotating your ankle, opening and closing your hand, or moving your neck are some of the common ways this can happen. In some cases, popping is something you might feel rather than hear, especially in the knee.

When to See a Doctor

Although a popping joint can be startling, there is generally nothing that needs to be done unless it is accompanied by other, more concerning symptoms such as pain and swelling.

However, if there is evidence of an injury—even if there is no pain—you would be wise to see a doctor. This would include losing the range of motion in a joint or having a joint suddenly lock up after it pops

On their own, popping joints are not predictive of future problems. In cases of osteoarthritis, they may occur more frequently as the disease progresses. On the other hand, popping can often subside in those who have had an injury or surgery as they regain flexibility and range of motion through exercise and movement.

View Article Sources
  • Kawchuk, G.; Fryer, J.; Jeremko, J. et al. "Real-Time Visualization of Joint Cavitation." PLoS One. 2015; 10(4): e0119470DOI: 10.1371/journal.pone.0119470.;