Przejdź do treściClicking, cracking or popping by itself does not diagnose joint damage. The significance of a joint sound depends on when it started, whether it is accompanied by pain, swelling, locking or loss of function, and whether the same movement reliably reproduces it.
The same description can mean different things
People use similar words for very different sensations: a single pop, fine crackling with each bend, a tendon that can be felt snapping, or a sudden sound at the moment of injury. These do not all have the same mechanism. A sound can arise when joint surfaces separate rapidly and a gas cavity forms in synovial fluid, when a tendon or ligament moves over another structure, or when uneven or unstable structures move.
Real-time MRI during finger-joint cracking showed that the characteristic single crack was associated with rapid cavity formation rather than bones simply rubbing together. That finding should not be generalised to every sound from a knee, shoulder or hip; its main value is to show that an audible crack can have a mechanism that is not tissue damage.
Crepitus does not automatically mean damaged cartilage
The knee is a useful example. A meta-analysis of 103 studies involving 36,439 people estimated knee crepitus in about 41% of the general population and about 36% of people without pain. Crepitus was also more common in osteoarthritis and with some structural changes seen on imaging. However, the certainty of these estimates was low or very low, so the sound cannot be used either to diagnose osteoarthritis or to prove that a joint is healthy.
What matters more than how loud it is?
- Onset: has the sound been present for years, or did it start at the exact moment of an injury?
- Associated symptoms: is there pain, rapid swelling, loss of motion, instability or weakness?
- Reproducibility: does the same movement cause it every time, or was it a one-off event?
- Location: can you point to or feel the structure that is snapping?
- Function: is the joint merely noisy, or does it truly lock and prevent the movement from being completed?
It is worth describing “locking” precisely. Stopping a movement because of pain or apprehension is different from a mechanical block in which the joint cannot be freely straightened or bent. That distinction can change both the urgency and direction of assessment.
When does a joint sound need faster assessment?
A sudden pop during an injury deserves earlier assessment when it is accompanied by severe pain, rapidly increasing swelling, visible deformity, inability to bear weight, marked instability or persistent mechanical locking. New sensory loss, weakness, pallor or a cold limb also requires urgent assessment. By contrast, long-standing painless sounds without swelling or declining function can usually be assessed non-urgently.
How an orthopaedic surgeon reproduces the symptom during examination
During an examination, the important question is not only whether a sound can be heard, but which movement produces it and what happens to the joint, tendon or other structure at that moment. Comparing both sides and assessing active and passive movement can help. X-ray, ultrasound, MRI or CT should then be selected according to the suspected mechanism — not every click needs imaging, and no single scan explains every type of joint sound.
See how diagnostic tests answer different orthopaedic questions →
Sources
- Couch JL, King MG, De Oliveira Silva D, et al. Noisy knees – knee crepitus prevalence and association with structural pathology: a systematic review and meta-analysis. Br J Sports Med. 2025;59(2):126–132. DOI: 10.1136/bjsports-2024-108866. PMID: 39375004. This summary used the public abstract and bibliographic metadata for this paper.
- Kawchuk GN, Fryer J, Jaremko JL, et al. Real-Time Visualization of Joint Cavitation. PLoS One. 2015;10(4):e0119470. DOI: 10.1371/journal.pone.0119470. PMID: 25875374. Full text is open access.
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Content prepared by: Tomasz Poboży - orthopaedic surgeon.