Are Your Knees Popping ? Here is What it Could mean. Dr. Joseph Mercola
- The Chicago Voice
- Oct 7
- 4 min read
Knee popping, also called crepitus, is common and not always linked to arthritis, so hearing sounds alone does not mean your joints are deteriorating
A five-year study of young adults recovering from ACL surgery found that noisy knees were associated with early cartilage stress but did not predict long-term decline in function or pain
Exercise is one of the most effective ways to protect noisy knees, as strengthening the quadriceps, hamstrings, glutes, and calves helps stabilize the joint and reduces strain
Lifestyle strategies like stretching, weight management, and modifying high-impact movements are often more effective than surgery, which is rarely needed for crepitus
Collagen from high-quality supplements or bone broth supports cartilage, tendons, and ligaments, offering an extra layer of protection for long-term knee health
Have you ever tried standing up or stretching your legs — only to hear a loud cracking or grinding sound coming from your knees? Interestingly, there's a name for this unique sound — crepitus.1 Some simply call it their knees "popping."
However, when crepitus happens, especially in the knees, many people assume and worry that it's a sign of arthritis — a condition wherein the joints are inflamed, leading to swelling, stiffness, pain, and gradual loss of movement. The good news is that knee crepitus doesn't always mean you have arthritis. In fact, a recent study found no strong link between knee sounds and structural joint damage.
New Research Reassures Young Adults About Noisy Knees
A recent study published in the journal Arthritis Care & Research took a closer look at the mechanisms of the knee, particularly the cracking or popping sound that occurs when you move this joint. In particular, they looked at whether knee crepitus is an early warning sign of arthritis or simply a common, harmless byproduct of joint movement.2,3
•The study included 112 young adults with a median age of 28 — The participants were all recovering from anterior cruciate ligament (ACL) surgery. According to research, this particular group of people has a higher risk of developing arthritis; about half of people who suffer an ACL rupture develop arthritis symptoms and structural joint changes within 10 years — that's roughly 15 years earlier than those without knee injury.
•The study ran for over five years — The researchers used magnetic resonance imaging (MRI) scans and patient-reported outcomes to track osteoarthritis signs among the participants. And while the early results suggest a worrying trend, the longer-term follow-up told a different story.
•Knee crepitus is associated with cartilage damage but not long-term joint damage — According to the researchers, those with crepitus had 2.5 times greater rates of full-thickness cartilage defects in the kneecap region; they also reported worse pain and poorer function one year after surgery. However, over the next four years, there was no difference in pain or function between those with noisy knees and those with quiet knees.
•To put it simply, the sound did not predict continued joint decline — Instead, it was more of an early-phase marker of recovery stress rather than a permanent red flag. Despite starting out with more pain and functional limits after the surgery, those with crepitus caught up with the quiet-knee group over time. Their pain did not worsen, and their function did not keep declining. Instead, with proper rehab and activity, they improved just as much as their peers.
•These findings are reassuring especially for active young people who have undergone surgery after sustaining joint injuries — Having noisy joints and automatically associating them with disease could push you toward aggressive interventions or medications you do not need.
Dr. Adam Culvenor, head of the Knee Injury Research Group at La Trobe's Sport and Exercise Medicine Research Centre (LASEM), said this study "also highlights the importance of staying active and engaged in rehabilitation to avoid or delay osteoarthritis."4
So Why Does Knee Crepitus Occur?
In the video above, Dr. Jeffrey Peng, a nonoperative orthopedist and sports medicine specialist based in San Francisco, provides insights on why knee sounds occur and why they are not always a warning sign. The truth is that about half of the general population (41%, to be specific) experience knee crepitus at some point in their lives. "In most cases, crepitus is harmless and does not indicate a serious problem. Many people experience occasional knee sounds without any pain or long-term issues," he explained.5
•The specifics of crepitus are worth unpacking — The knee joint is complex, and is made up of bones, tendons, cartilage, ligaments, and synovial fluid. These mechanisms can play a role in why crepitus occurs. For example, the release of gas bubbles leads to knee sounds. These bubbles form and collapse inside the fluid that lubricates your joints. However, the popping sound that comes from it is no more dangerous than cracking your knuckles; it's also painless.
•Another common cause is the movement of tendons or ligaments — Peng explains that when tendons and ligaments briefly shift over bones, they produce a snapping or clicking sensation. These mechanical shifts are often harmless and tend to happen during squats, lunges, or even when you stand up. "While this is usually not a sign of damage, it may be a concern if accompanied by pain or feelings of instability," he added.
•Nevertheless, there are situations when crepitus is a sign of something serious — This is when crepitus occurs along with cartilage wear, meniscus (a crescent-shaped cartilage) tears, or loose fragments in the joint. In these cases, the noise is joined by pain, swelling, or locking. This is your body's way of alerting you that the joint structure has been disrupted. If crepitus suddenly manifests after an injury, these tears within the joint could be the cause.
"Research has found that the presence of crepitus could signal that structural changes like cartilage damage or bone spurs are happening in the joint. In fact, 81% of people with diagnosed knee osteoarthritis experienced knee crepitus. That's a significant number, which is why it's so often discussed in relation to arthritis," Peng explained.
•Time-related details also matter — If crepitus stems from normal joint function, the noise may persist but does not lead to degeneration. But if noise results from conditions like osteoarthritis, symptoms can worsen gradually, especially without joint care.
Analysis by Dr. Joseph Mercola
