Crepitus

What does crepitus sound like?

Reminiscent of crushing a packet of crispie rice breakfast cereal, in the early stages crepitus can be felt, rather than heard, by laying the palm of the hand on the kneecap and bending the knees (while standing).

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What causes crepitus?

The origin of the sound is apparently the presence of fine gaseous bubbles in the soft tissues, which arise from the soft tissues.

Although the presence of crepitus is alarming, it just means that the knee is 'not happy' but is not diagnostic in its own right.

• Quote from peer-reviewed paper:

  "....Individuals with knee osteoarthritis and knee crepitus have slightly lower self-reported physical function and knee-related quality of life (small or trivial effect). However, the presence of knee crepitus is not associated with objective function or knee strength...."

  Citation: Pazzinatto MF, de Oliveira Silva D, Faria NC, Simic M, Ferreira PH, Azevedo FM, Pappas E. What are the clinical implications of knee crepitus to individuals with knee osteoarthritis? An observational study with data from the Osteoarthritis Initiative. Braz J Phys Ther. 2019 Nov-Dec;23(6):491-496. doi: 10.1016/j.bjpt.2018.11.001. Epub 2018 Nov 16. PMID: 30471964; PMCID: PMC6849337.

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What are the implications of crepitus?

The sudden awareness of crepitus in one's knee can be very alarming, especially if the sound is loud or the sensation coarse.

It always implies that the joint is under stress, but it is very non-specific.

• Quote from peer-reviewed paper:

  "....It is important to differentiate between physiological noise and pathologic noise. In most cases, noise after surgery is simply the perception of noise that had been present previously due to emotional concerns....."

  Citation: Song SJ, Park CH, Liang H, Kim SJ. Noise around the Knee. Clin Orthop Surg. 2018 Mar;10(1):1-8. doi: 10.4055/cios.2018.10.1.1. Epub 2018 Feb 27. PMID: 29564040; PMCID: PMC5851845.

• Quote from peer-reviewed paper:

  "....The best way to differentiate between physiological noise and pathological noise is by checking for pain and swelling/effusion in the knee joint...."

  Citation: Song SJ, Park CH, Liang H, Kim SJ. Noise around the Knee. Clin Orthop Surg. 2018 Mar;10(1):1-8. doi: 10.4055/cios.2018.10.1.1. Epub 2018 Feb 27. PMID: 29564040; PMCID: PMC5851845.

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Forum discussions

• Patela shaving [sic]

  Patient discussing crepitus from a cartilage defect under the patella.

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