If your knees crack, pop, or make that weird grinding sound when you stand up or climb stairs, you are not alone. Those noises can show up in older adults, younger people, and everyone in between, no matter how athletic they are. In a recent episode of the podcast ‘No Appointments Necessary’, physician Dr. Amir Khan addressed a listener question about whether food or exercise can help with noisy knees. His main message was reassuring, as long as the sound is not paired with pain.
Dr. Khan explained that harmless popping often comes down to normal movement inside the joint. “If it doesn’t hurt and isn’t tender to the touch, it’s probably fluid in the joint moving as you bend or straighten your leg,” he said. Knees are complex hinges with cartilage, ligaments, tendons, and a capsule filled with synovial fluid that helps everything glide. When you change position, pressure shifts, tissues slide, and tiny bubbles can form or move within that fluid. The result can be a pop that feels dramatic but is not necessarily dangerous.
He also pointed to another common explanation that can feel more alarming when you notice it. “But sometimes something called crepitus in the knee can happen.” Crepitus is a term clinicians use for crackling, grinding, or crunching sensations in a joint during motion. People sometimes describe it as sand under the kneecap, especially when straightening the leg from a bent position. On its own it can be benign, but it becomes more meaningful when it shows up with other symptoms.
To help people tell the difference between ordinary noise and something worth checking, Dr. Khan suggested a simple at home feel test. Place your palm over your kneecap, then slowly straighten and bend the leg. If you notice roughness, vibration, or a gritty sensation, that can be the kind of crepitus he is talking about. This is not a diagnosis, but it can help you describe what you are experiencing more clearly if you decide to speak with a clinician.
The bigger red flag is when popping is not the only thing happening. Dr. Khan brought up osteoarthritis as a possible reason for knee noises when they come with discomfort or swelling. The UK National Health Service, often referred to as the NHS, describes osteoarthritis as the most common form of arthritis and notes that it can cause joint pain and stiffness. Alongside cracking or creaking during movement, people may also notice swelling, tenderness, and reduced flexibility. Symptoms vary widely, so two people can have the same condition and feel very different day to day.
If osteoarthritis is part of the picture, the advice can feel counterintuitive because many people assume rest is the safest option. Dr. Khan emphasized the importance of staying active rather than freezing up and avoiding movement. “Movement helps lubricate the joint and absorb load better,” he explained. Gentle, regular motion helps keep the muscles around the knee engaged, supports joint function, and can reduce the sense of stiffness over time. Avoiding activity completely can lead to weaker muscles and a joint that feels even less stable.
He also encouraged people not to abandon the activities they already tolerate well. “Keep walking, running, or doing the exercises you normally do. And watch for a healthy body weight because it reduces pressure on the joints.” That does not mean pushing through sharp pain or ignoring swelling, but it does mean finding a level of movement that is sustainable. For some people that might be brisk walking and strength training, while others may do better with cycling, swimming, or controlled resistance exercises. The goal is to keep the knee moving and the surrounding muscles strong without constantly aggravating symptoms.
Another point Dr. Khan made is that osteoarthritis often develops gradually through small changes in the joint over time. That slow build is one reason people may dismiss early signs, especially if the only symptom at first is noise. Experts generally advise seeing a doctor if the popping persists and is paired with pain, swelling, stiffness, or limited range of motion. Those added symptoms can signal inflammation, cartilage wear, tendon irritation, or other issues that deserve a proper assessment. Getting evaluated can also help you avoid guessing and can point you toward a plan that fits your body and activity level.
It helps to understand what the knee is dealing with biomechanically because it is asked to do a lot. The knee joint primarily connects the femur and tibia, with the patella acting like a protective pulley that improves leverage for the quadriceps. Cartilage covers the bone ends to reduce friction, while menisci act as shock absorbers. Ligaments stabilize the joint and tendons connect muscles that control movement. When any of these parts are irritated, weakened, or worn down, the joint can start to feel and sound different during everyday tasks.
Knee sounds can also be influenced by factors that are not inherently pathological. Tight muscles around the hips and thighs can change tracking of the kneecap, making sensations more noticeable. After long periods of sitting, tissues may feel stiff until they warm up, which can make pops more frequent at first movement. Strength imbalances between the quadriceps and hamstrings can also affect how the joint loads with each step. That is why many rehab plans focus on strengthening the hips and thighs, improving mobility, and gradually building tolerance rather than chasing a quick fix.
If your knee popping is painless, the most practical approach is usually observation and smart movement. Pay attention to whether the sound is new, whether it is getting more frequent, and whether it is starting to come with swelling or aching afterward. If you are adding new workouts, increase intensity gradually and give your joints time to adapt. If symptoms are appearing, consider a check in with a healthcare professional, especially if daily activities like stairs, squatting, or walking begin to feel limited. A clear evaluation can help you protect the joint while staying active, which is exactly what most knees need to stay happy.
Have you experienced knee popping, and what helped you figure out whether it was harmless or a sign to get checked, share your thoughts in the comments.
