Noisy Knees: Should You Worry?

The short answer
Usually no — but it depends on whether the noise comes with pain, swelling or giving way. A knee that clicks, pops or cracks without any of these accompanying symptoms is almost always harmless. A knee that makes noise alongside pain, swelling or instability is telling you something worth investigating.

What causes noisy knees?
The medical term for joint noise is crepitus — a broad term covering everything from the occasional painless click to the consistent grinding sound of advanced osteoarthritis. Several different mechanisms produce knee noise, and they are not all clinically equal.

Gas bubble release — the most common and most harmless cause of joint popping. The joint fluid surrounding the knee contains dissolved gases. When the joint is rapidly moved or stretched, pressure changes cause gas to come out of solution and form a bubble — which then pops. This is what happens when you crack your knuckles and it is completely harmless. There is no evidence that habitual knuckle or joint cracking causes arthritis.

Tendon and ligament movement — tendons and ligaments that track around the knee can sometimes snap or click as they move across bony prominences. The iliotibial band snapping over the lateral femoral condyle, or the patellar tendon shifting, produces a clicking sound that is usually painless and more of an annoyance than a clinical concern. If the snapping is associated with pain — particularly lateral knee pain during running or cycling — it may indicate iliotibial band syndrome and is worth assessment.

Cartilage surface changes — the articular cartilage that lines the joint surfaces of the knee can develop surface irregularities over time. When irregular cartilage surfaces move against each other they produce a grinding or grating sound — often described as feeling like sand in the joint. This is more characteristic of osteoarthritis or chondromalacia patella and is more clinically significant than gas-release popping, particularly when associated with pain.

Meniscal tears — a torn meniscus can produce clicking, clunking or locking of the knee as the torn fragment catches in the joint. Unlike the painless click of gas release, meniscal clicking is typically associated with pain and often with a catching sensation — a mechanical feeling of something moving in the joint that isn't supposed to. See our meniscal tears page for more detail.

Plica syndrome — the plica is a fold of synovial tissue inside the knee that can become irritated and inflamed, producing a clicking or snapping sensation as it catches over the medial femoral condyle during knee flexion. It produces a consistent, reproducible click at a specific point in the movement range and is often associated with anterior or medial knee pain.

When should you get noisy knees assessed?
Noise alone — without any other symptoms — rarely warrants urgent physiotherapy assessment. But the following combinations of symptoms do:

Noise plus pain. Any consistent knee noise associated with pain — whether sharp, dull or aching — warrants assessment. The pain helps identify which structure is producing the noise and guides appropriate management.

Noise plus swelling. Swelling inside the knee joint (effusion) alongside noise suggests an intra-articular process — meniscal injury, cartilage damage or inflammatory joint disease — that needs clinical assessment. Swelling outside the joint may indicate bursitis.

Noise plus giving way. A knee that clicks and then gives way — a sudden loss of support — suggests ligamentous or meniscal involvement that requires assessment. ACL injuries and significant meniscal tears commonly present with giving way.

Noise plus locking. A knee that catches or locks — becomes unable to fully straighten — alongside clicking is a classic presentation of a displaced meniscal tear and requires prompt assessment.

New noise after an injury. A knee that starts clicking after a specific traumatic event — a fall, a contact injury, an awkward landing — should always be assessed, even if initial pain settles quickly. Ligament and meniscal injuries can produce deceptively mild early symptoms that worsen with continued loading.

Noisy knees in younger people
Clicking knees in teenagers and young adults are extremely common and usually harmless — the most frequent cause is gas-release popping or normal tendon movement around a still-developing joint.

However patellofemoral pain syndrome and chondromalacia patella — both of which produce anterior knee noise and pain — are also common in this age group and respond very well to physiotherapy. If a young person has knee noise alongside anterior knee pain with stairs, squatting or prolonged sitting, physiotherapy assessment is worthwhile.

Noisy knees in older people
In older adults, persistent grinding or grating of the knee — particularly with pain, morning stiffness and reduced range of motion — is a characteristic presentation of knee osteoarthritis. Osteoarthritis does not have to be managed passively. Exercise-based physiotherapy, load management, quadriceps strengthening and activity modification produce meaningful improvements in pain and function for most people with knee osteoarthritis — regardless of what the imaging shows. The correlation between the severity of X-ray findings and the severity of symptoms is surprisingly poor — many people with significant cartilage loss on imaging have minimal symptoms, while others with mild imaging findings have significant pain. Treating the person, not the scan, is the correct approach.

What to do
If your knees are noisy but painless, no action is needed — monitor for any change in symptoms and don't let the noise itself cause worry.

If your noisy knees are associated with any of the symptoms above — pain, swelling, giving way, locking or noise following injury — book an assessment with one of our physiotherapists. A thorough clinical assessment will identify the likely source of the noise, determine whether imaging is needed, and provide a clear management plan.
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Our physiotherapists Mauricio Bara and Eliane Machado both have specific expertise in knee assessment and rehabilitation and are members of the Australian Physiotherapy Association.
To book or find out more, call us on 07 3706 3407 or book online below.