Snap, Crackle, Pop: What Does Knee Popping Mean?

July 29, 2022 – 3 min read

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Hearing a loud pop when you bend your knee or make other movements can be unsettling. But is knee popping something you should be worried about? In most cases, the answer is no. Occasional popping or creaking in the knees is usually a result of the normal action of the joint. However, if you have pain or swelling along with the popping or it happens frequently, it could be a sign of a more serious problem.

Causes of knee noises 

Knee popping, also called knee crepitus, is usually harmless. A protective substance called synovial fluid covers the knee joint, and tiny gas bubbles can form in the fluid. When you move your knee, the bubbles burst, causing a popping noise. Other times, ligaments may make a snapping noise as they pass over a bone structure and then move quickly back into place.

In some cases, however, knee noises indicate a problem, such as arthritis. Injuries can also cause knee popping.

Meniscus tear

The meniscus is a disk of cartilage that stabilizes the knee and acts as a shock absorber between the upper and lower leg bones. Tears often happen from twisting the knee while playing sports.

Chondromalacia patella

Also known as runner’s knee, chondromalacia patella occurs when cartilage behind the kneecap breaks down, which often occurs from overuse.

Degenerative conditions

As people age, knee cartilage can degenerate, as can the meniscus. Falling or twisting the knee can sometimes lead to tears in the ligaments around the knee joint, and the ligaments themselves can degenerate with age. These conditions may result in knee pain and related noises.

When to see a doctor to diagnose knee popping 

You can usually safely ignore occasional pops or creaks from your knees, as long as you have no other symptoms. But make an appointment with your doctor if:

  • Knee popping is accompanied by pain, or you have frequent pain on the side or front of the knee.
  • Using the joint for a period of time, such as when walking, causes pain.
  • You hear a pop at the same time as an acute knee injury.
  • Your knee looks swollen or becomes stiff or tender to the touch.

After performing a physical examination and ordering appropriate tests—which may include medical imaging—your doctor will recommend a care plan to reduce pain and improve knee function. Medical advice for knee problems may include at-home management such as rest and elevation. Depending on your diagnosis, your doctor may also order treatments such as nonsteroidal anti-inflammatory medications, physical therapy or surgery.

Touchstone Medical Imaging offers affordable outpatient imaging studies to help diagnose knee issues. After receiving an order for a scan from your doctor, make an appointment at one of our many convenient centers.

Advanced imaging for knee popping

If your doctor suspects an injury or condition is causing your knee popping, he or she will likely order imaging to collect more detailed information and confirm the diagnosis and treatment. Medical imaging can help differentiate between types of injuries and reveal signs of arthritis.

Common types of imaging that can help your doctor diagnose knee issues include:

  • Magnetic resonance imaging (MRI): An MRI uses a magnetic field and radio waves to create detailed images without using radiation.
  • Computerized tomography (CT) scan: Using advanced X-ray technology, a CT scan creates comprehensive images of sections of the body.

Touchstone Medical Imaging offers the latest imaging technology interpreted by subspecialized, fellowship-trained radiologists. With a doctor’s order in hand, schedule an appointment for imaging at the center nearest you.