Woman with knee pain.

Is This Serious? Why Do My Knees Crack?

Kerrie-Ann Bernard Is this serious?, Knee pain


In yoga class, at the gym or even stooping down to pick something up during the workday, we’ve all heard the loud pop or cracks that can come with a full knee bend. If it happens a lot you want to know: is this serious?

While contacting your doctor about ongoing issues is always a wise decision, it’s good to know what you’re dealing with prior to making that appointment. So we’ve pulled together a summary of the symptoms, possible causes and treatment options to help you navigate this cracking joint.


You hear a cracking or popping when the knee hits its full range of motion.

For most people, it’s completely harmless. A knee crack or pop happens as a natural result of aging as the cartilage on the joint starts to wear it becomes uneven in certain places. What you hear could be the rough spots moving over one another or the tissue that connects bones together (called ligaments) tightening or even just air bubbles “popping” from a change in joint pressure. Nothing to worry about.

Worried that too much cracking will lead to arthritis? Well, you can breathe a little easier: The theory that cracking joints will lead to arthritis has no research behind it.

However, if the crack or pop comes is accompanied by pain or swelling, you’ll want to take the noise more seriously.

Possible causes

Pain or swelling in the knee, combined with the cracking noise, is a sign that something is out of alignment. It could be one of the following:

Meniscus tear

The rubbery C-shaped disc (meniscus) is designed to cushion your knee, absorbing shock and spreading the weight of impact evenly across your bones. Tearing can happen because of an unexpected twist or turn, especially during athletic activity, often when the knee moves but the foot stays planted. As you age, you have a higher risk of tearing the meniscus, even with everyday activity.

Cartilage injury or wear

In an injury, knee cartilage can break off and catch on the joint, which causes pain and swelling. Or, the cartilage may wear down from arthritis, which leads to a painful grinding feeling during movement.


Depending on the extent and location of the injury, as well as your current physical state, treatments could include the following:

  • Rest
  • Physical therapy
  • For meniscus tears specifically: surgery (usually minimally invasive) to repair the tear or remove the torn section, either partial or total meniscectomy


The key is to seek treatment early, which leads to a faster and more effective recovery. If you’re at all worried, it’s best to book an appointment with a physical therapist for a full assessment.


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