Crepitus, which is sometimes called crepitation, is when repeated crackling sensations or sounds come from a joint or tissue that can be associated with a fracture, swelling, or inflammation. These are palpable, and sometimes audible, crunching, grinding, creaking, grating or other rough sensations or sounds produced by joint movements, which can often be felt by a palpating hand placed over the moving part during active or passive movement. Although crepitus is usually a sign of pathological change in the tissues and may be experienced as pops, snaps, or cracks, not all joint sounds on movement are a problem as sometimes clicking sounds or other sounds from a joint are normal, such as those that are commonly experienced in the normal knee. There is not always pain during crepitus and when there is pain which accompanies a joint noise or other sensation, the two events may not always be related.
Crepitus can be caused by many different changes in the tissues, involving both soft or hard bony tissues:
Articular crepitus
Originates from the joint surfaces. This can result in a fine crepitus from a mild roughening of the joint surfaces since they glide over each other during movement. It is caused by inflammation, or from longstanding chronic cases, such as rheumatoid arthritis. More advanced cases can produce a coarse crepitus due to the more pronounced roughening of the joint surfaces.
Tendinous crepitus
A creaking leathery (snowball) crepitus from inflamed tendons (tenosynovitis), caused by traumatic roughening of the tendon surface and the inner part of its sheath. Sometimes a more coarse crepitus may be felt in chronic rheumatoid or tuberculous tenosynovitis.
Osseous crepitus
Occurs when a bone fracture is present and the limb is moved. This usually comes with a great deal of pain. This may also be associated with a bone tumor or gas gangrene that has eroded the cortex.
Bursal crepitus
Caused by an inflamed joint bursa. The subdeltoid bursa is usually the example given, which leads to crepitus when inflamed and which can lead to creaking when moving the arm, even after the inflammation has subsided.
Muscle crepitus
Muscle or muscular crepitus has been seen in two situations:
Tenosynovitis of the two extensors of the long abductor of the thumb in the distal forearm. This crepitus is usually locally felt but may produce crepitus felt over the entire muscles possibly up to the elbow.
A lesion of the musculotendinous junction of the tibialis anterior muscle that produces localized crepitus.
Course Crepitus vs. Fine Crepitus
A coarse crepitus is a more pronounced crepitation which can often be heard as well as felt. This type of crepitation is often described as a crackling and if hands are placed over the area it can be felt. Such coarse crepitation usually occurs where degenerative changes have occurred, as in the neck and shoulder. In that past middle-age a normal a coarse crepitation, or grating sensation, is often felt in the neck or cervical area upon movement. In the larger joints subject to body-weight, such as the knees, such crepitus is more common as the cartilage itself can become worn (arthrosis) causing it to become fragmented. In severe cases, the cartilage can wear through allowing, during some movements, bone to run rub against bone, producing a creaking or “cogwheel” sensation.
Fine crepitus occurs in rheumatoid arthritis or the early stages of arthrosis and produced a fine rubbing sensation. However, certain inflammatory processes can produce fine crepitus which can be resolved. 1Ombregt, Ludwig. A System of Orthopaedic Medicine – E-Book. Churchill Livingstone, 2013.,2Kinirons, Mark T., editor. French’s Index of Differential Diagnosis an A-Z. 16th ed., CRC Press, 2017.
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