If your knees click when you squat, your neck cracks when you turn your head, or your fingers pop when you bend them, you are not alone. Clicking and popping joints are one of the most commonly reported physical experiences — and one of the most commonly misunderstood.
For many people, the sound triggers immediate concern. Is something broken? Is it arthritis? Am I damaging my joints? In most cases the answer is reassuring — but understanding what is actually causing the sound, and when it is worth paying attention to, is genuinely useful information.
What Causes Joints to Click?
There is not a single explanation for joint clicking. Several distinct mechanisms can produce the sounds and sensations that people describe, and identifying which one is occurring matters for understanding whether it requires attention.
- Joint Cavitation
This is the most well known cause of joint clicking and the mechanism behind knuckle cracking and the sounds produced during chiropractic adjustments. Joints are surrounded by a capsule filled with synovial fluid — the lubricating fluid that nourishes and protects joint surfaces. This fluid contains dissolved gases. When the joint is moved in a way that rapidly changes the pressure within the capsule, these gases form a bubble and collapse — producing the familiar popping sound.
Joint cavitation is generally harmless. The long-standing myth that cracking knuckles causes arthritis has been thoroughly investigated and not supported by evidence. The sound can feel satisfying and may be accompanied by a brief sense of relief or increased range of motion — but it does not indicate damage.
- Tendons and Ligaments Snapping Over Bony Prominences
A second common cause of joint clicking is a tendon or ligament snapping over a bony landmark as the joint moves through its range. This is particularly common at the hip — where the iliotibial band or the iliopsoas tendon can snap over the greater trochanter or the front of the hip joint — and at the ankle and knee.
This type of clicking tends to be more of a thud or snap than a pop, is often reproducible with specific movements, and may or may not be accompanied by discomfort. When it is painless and not associated with instability, it is generally not a cause for concern. When it is painful, persistent, or accompanied by other symptoms, it warrants assessment.
- Joint Surfaces Moving Against Each Other
In joints where the cartilage has become uneven — whether through wear, previous injury, or early degenerative change — the joint surfaces can produce grinding, clicking, or crepitus as they move against each other. This type of sound is often described as more of a grating or grinding sensation rather than a sharp pop.
Crepitus of this kind is common and does not automatically indicate significant joint damage. Many people with audible crepitus in their knees, for example, have entirely normal joint function and no pain. However, crepitus that is accompanied by pain, swelling, or a locking sensation should be assessed to determine whether the underlying joint health needs attention.
- Clicking Related to Hypermobility and Instability
As discussed in our previous blog on hypermobility, joints that move beyond their normal range can produce clicking as tendons, ligaments, and joint surfaces shift through these excessive ranges. This type of clicking is different from normal cavitation — it tends to be repetitive, occurs during everyday movements, and is often accompanied by a sense of looseness or instability rather than relief.
Clicking in the context of hypermobility is a signal that the joint is not being adequately controlled through its available range of motion. This is where stability and strengthening work becomes important — not to limit the range, but to develop the muscular control needed to manage it safely.
- Clicking After Injury or Surgery
Clicking that develops following a joint injury or surgical procedure deserves specific attention. New clicking after a knee injury, for example, may indicate a meniscal tear or loose body within the joint. Clicking after shoulder injury may reflect changes in the rotator cuff or labrum. When clicking follows a specific traumatic event and is accompanied by pain, swelling, or a change in function, it should be assessed promptly rather than assumed to be benign.
When Should Clicking Be Investigated?
Most joint clicking is benign and does not require treatment. However, the following features suggest that a clinical assessment is worthwhile — clicking that is accompanied by pain either during or after movement, clicking that has developed following a specific injury or incident, clicking associated with swelling, warmth, or visible changes around the joint, clicking accompanied by a sense of instability or giving way, clicking that is new or has changed in character, and clicking in a young person that is persistent and associated with any of the above.
The absence of pain does not always mean the absence of a problem — but in most cases painless clicking in otherwise well-functioning joints is a normal variation rather than a pathological finding.
What Clicking Can Tell Us Clinically
At Aret Chiropractic, joint clicking is never dismissed as insignificant without first understanding the context. The location of the click, the movement that produces it, whether it is painful, and how it relates to the patient’s broader symptom picture all provide useful clinical information.
As discussed in our hypermobility blog, a joint that clicks excessively may be doing so because a neighbouring joint is not moving enough — placing compensatory demand on the symptomatic joint. Identifying and addressing this movement chain imbalance is often as important as working directly on the clicking joint itself.
If your joints have been clicking and you are unsure whether it is something to be concerned about, we are happy to take a look and give you a clear answer. Call us on (02) 8018 8883 to speak with one of our Chiropractors at Aret Chiropractic in North Ryde, or book online for a consultation.
References
Castellanos, J., & Axelrod, D. (1990). Effect of habitual knuckle cracking on hand function. Annals of the Rheumatic Diseases, 49(5), 308–309.
Dunning, J., et al. (2012). Cavitation sounds during cervicothoracic spinal manipulation. Journal of Orthopaedic & Sports Physical Therapy, 42(5), 413–420.
Farrokhi, S., et al. (2011). Pathomechanics of patellofemoral joint cartilage and subchondral bone. Sports Medicine and Arthroscopy Review, 19(2), 103–112.
Keer, R., & Grahame, R. (2003). Hypermobility Syndrome: Recognition and Management for Physiotherapists. Butterworth-Heinemann.
Unsworth, A., et al. (1971). Cracking joints: a bioengineering study of cavitation in the metacarpophalangeal joint. Annals of the Rheumatic Diseases, 30(4), 348–358.