Many people experience a crackling, grating, or popping sensation when bending the knee. The medical term for this is knee crepitus.

A person with knee crepitus can usually feel the crunching or cracking sensation by placing a hand over the knee cap as the knee bends and straightens.

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Occasional popping or cracking can be normal and is generally considered harmless. However, if the noise occurs regularly and is painful, it may indicate osteoarthritis, rheumatoid arthritis, or patellar dysfunction. People who have regular, noticeable knee popping noises accompanied by pain and/or swelling are advised to seek a medical evaluation.

See What Causes a Swollen Knee (Water on the Knee)?


Arthritis Symptoms Associated Knee Crepitus

Crepitus caused by knee arthritis is often accompanied by other symptoms, such as:

  • Pain while walking or bending the knee
  • Knee stiffness that improves with gentle stretching or exercise
  • Knee tenderness or soreness, most commonly on the inside of the knee (medial knee)
  • Occasional swelling of the knee

Many things can cause the creaking or crunching sensation while flexing and extending the knee. A doctor can conduct a clinical exam to determine if knee symptoms are caused by arthritis or another something else, such as patellar motion.

See 6 Types of Arthritis that Affect the Knee


Knee Crepitus Treatment

Most people experience the occasional knee pop or crackle, especially when kneeling to the floor or with repetitive knee extension and flexion. If crepitus is painless, it is usually not a concern. If there are other symptoms, however, it is generally advisable to seek a diagnosis with an appropriate health care professional. A health care professional evaluate the patient and determine if the knee crepitus and other symptoms are caused by arthritis or another condition.

For an in-depth review of knee arthritis symptoms and treatments, see Knee Osteoarthritis

Dr. Rachel Brakke is a physiatrist specializing in sports medicine and musculoskeletal injuries at the University of Colorado Hospital. She serves as an Associate Professor in the Department of Physical Medicine and Rehabilitation and as fellowship director for the Pain Medicine Fellowship at the University of Colorado School of Medicine.