Why do I feel a grinding sensation in my knee when I walk?

Understanding Knee Grinding and Discomfort: Causes and Practical Solutions

Welcome back to the NuovaHealth Q&A blog series. Today we’re answering a question from James, who has noticed a grinding sensation in his knee after becoming more active. If you’ve ever felt the same, you’re not alone. Let’s get straight into it.

Hi NuovaHealth,

I wanted to ask for your expertise on something that’s been bothering me lately. I’ve noticed a grinding sensation in my knee when I walk, and it’s starting to worry me. I haven’t experienced any major injuries, but I’ve been more active recently, trying to get in shape. Could this sudden increase in activity be the cause? I’m generally in good health, but I’m wondering if there’s anything specific I should be concerned about or any steps I can take to alleviate the discomfort. Any advice or insight would be greatly appreciated!

Thanks so much, James

Hello James, thanks for reaching out. First, let me reassure you: a grinding sensation alone — especially without pain or swelling — is very common and often harmless. And yes, a sudden increase in activity can absolutely make your knees noisier. So you’re on the right track to ask about it.

Please note: this information is for guidance purposes and is not a substitute for individual medical advice. If any of the red flags we mention below apply to you, please see a healthcare professional.

What Is That Grinding Feeling?

The medical term for that grinding, crunching, or popping sensation is crepitus. There are several different reasons why it happens — some completely normal, others relating to how the joint is structured. We’ll go through them one by one, so you can understand what’s likely going on with your own knee.

Common Causes of Knee Grinding

Let’s start with the most common reasons — the ones that are usually nothing to worry about.

1. Gas Bubbles in the Joint Fluid

Your knee joint sits inside a capsule filled with a lubricating fluid called synovial fluid. When you bend or straighten your knee, the space inside this capsule changes size. As the space expands, the pressure in the fluid drops, causing tiny gas bubbles to form. When the knee returns to its resting position, the pressure normalises and the bubbles quickly dissolve, producing a popping or grinding sound. This is the same harmless process that makes the sound when you crack your knuckles. If this is the cause, the noise is simply a shift in pressure — nothing to worry about.

2. Soft Tissue Movement

Tendons are the strong, flexible bands that connect muscle to bone. Around the knee, several tendons pass close to the bone and can glide over small bony prominences as you walk. If a tendon happens to slide over a slight bump on the thigh bone (femur) or shin bone (tibia), you may feel or hear a grind. This is simply a normal variation in how soft tissues interact with bone. In the absence of pain or swelling, it doesn’t require treatment.

3. Muscle Imbalance and Kneecap Tracking

Your kneecap (patella) sits in a groove on the front of your thigh bone and is guided by the pull of your thigh muscles. The quadriceps muscles on the front of your thigh and the hamstrings on the back help keep the kneecap centred as you move. If one of these muscle groups becomes significantly stronger or tighter than the other, it can pull the kneecap slightly to one side. This can cause the underside of the kneecap to rub against the thigh bone, producing a grinding sensation.

Muscle imbalance isn’t the only reason the kneecap might not track properly. Sometimes the groove itself is slightly different in shape, or the soft tissues around the kneecap are naturally tighter on one side. Over time, this persistent rubbing can soften and roughen the cartilage on the underside of the kneecap — a condition called chondromalacia patellae, sometimes known as runner’s knee. The good news is that muscle imbalance, at least, is often correctable with simple strengthening exercises, which we’ll cover shortly.

What this means for you: if your knee only makes noise and doesn’t hurt, it’s likely one of these common, benign causes. But if you notice the grinding is accompanied by pain, swelling, or a feeling that the knee is catching, keep reading — that takes us into other territory.

Arthritis and Related Conditions

So far we’ve looked at reasons that are usually nothing to worry about. Now let’s consider changes that happen inside the joint itself.

Osteoarthritis

Cartilage is the smooth, tough tissue that covers the ends of the bones where they meet inside a joint. In osteoarthritis, this tissue gradually becomes thinner and less even. As the cartilage wears down, the two bones begin to sit closer together, and the surfaces that were once smooth become rough and irregular. When the knee moves, those rough surfaces rub against each other, which can create a grinding or grating feeling.

Several factors can increase the risk of developing osteoarthritis. Repetitive high-impact activities, such as running or jumping, place repeated stress on the cartilage and can speed up its breakdown. Structural alignment also plays a role: for example, a wider pelvis can change the angle at which the thigh bone meets the knee, affecting how load is distributed across the joint. In women, hormonal changes can influence joint laxity and cartilage health, though the exact relationship is not yet fully understood. That said, keeping the thigh muscles strong and avoiding excessive high-impact loading can help protect the cartilage over time.

What this means for you: if your grinding comes from osteoarthritis, the focus shifts to preserving the cartilage you have and keeping the joint moving smoothly — which brings us back to the practical steps further down.

Inflammatory Arthritis

Conditions like rheumatoid arthritis and gout can also cause a grinding sensation, but they usually come with other symptoms. In rheumatoid arthritis, the lining of the joint becomes inflamed and thickened. This inflamed tissue takes up space inside the joint, and as it rubs against the bones and cartilage, it can interfere with smooth movement. In gout — a form of arthritis caused by uric acid crystals forming in the joint — those crystals are abrasive and can damage the cartilage surface over time, leading to a rough feeling when the knee moves. In both conditions, you would likely notice pain, warmth, and swelling in addition to the grinding.

If your knee is also swollen, warm, or painful, that’s worth a proper assessment.

Other Possible Causes

Beyond arthritis, there are a few other conditions that can create a grinding feeling. These are less common, but still worth understanding.

• Meniscal tears or degeneration: The meniscus is a wedge-shaped piece of cartilage in the knee that helps spread load evenly. If it tears or becomes worn, its surface becomes irregular. When the bones move against this uneven surface, you may feel a grind or catch.
• Bursitis or plica syndrome: A bursa is a small fluid-filled sac that reduces friction between soft tissues and bone. A plica is a fold in the joint lining. Both can become irritated or thickened from repetitive movement or direct pressure. Once inflamed, they can catch or rub against the bones and tendons around the knee, producing a grinding sensation.
• Loose bodies: Occasionally, small fragments of bone or cartilage break away from the joint surface and move around inside the knee. When one of these fragments gets between the bones during movement, it can cause grinding, clicking, or a feeling of something shifting inside the joint.

If any of these sound familiar, especially with locking or giving way, it’s worth seeing a professional.

Rare Causes — Information, Not Alarm

Very rarely, more serious conditions can affect the knee. These include benign or malignant tumours that develop in or near the joint, or a condition called synovial chondromatosis, where small nodules of cartilage form within the joint lining. Such conditions are exceptional, and they almost always produce additional symptoms — persistent pain, noticeable swelling, weakness, or a marked change in how well the knee moves. If you only have a grinding sensation without any of those signs, these conditions are not a likely explanation. We mention them here simply for completeness.

When Should You See a Doctor?

Grinding on its own doesn’t usually mean something is wrong. But you should have the knee checked if you notice any of the following alongside the grinding:

• Sharp pain when you walk or put weight on the knee
• Noticeable swelling that doesn’t settle after a few days
• The knee locks — it gets stuck in one position and you have to gently wiggle it free
• The knee gives way — it suddenly feels unstable and you feel as if it might buckle
• You cannot bear weight on the affected leg at all
• Heat and redness around the joint, which could indicate inflammation or infection
• Morning stiffness that lasts longer than 30 minutes after you get up
• The kneecap looks or feels as if it is moving out of place during movement

If any of these apply, a GP or physiotherapist can carry out a proper assessment and identify the underlying cause.

Practical Steps to Ease the Discomfort

There is a lot you can do on your own to reduce knee grinding, especially if it’s linked to a recent change in activity. Here are some approaches that work.

1. Modify your activities: Exercises like swimming and cycling let your knee move through its natural range of motion without the repeated impact of running or jumping. This means you can stay active while reducing the compressive force on the joint surfaces.
2. Strengthen the muscles around your knee: Strong quadriceps help keep your kneecap centred in its groove, which reduces uneven pressure underneath. Simple exercises such as wall sits, straight-leg raises, or step-ups can be very effective, provided they are comfortable for you.
3. Increase your activity gradually: If you have recently become more active, sudden spikes in mileage, intensity, or frequency are a common trigger for noisy knees. Building up week by week gives your joints time to adapt.
4. Pay attention to your weight: For those who are carrying extra weight, even a modest reduction can noticeably reduce the load through the knees. This is about supporting your joints in the long term, not about any fixed ideal.
5. Use hot and cold therapy: Applying an ice pack after exercise can help settle any inflammation or swelling. Using a warm compress before activity helps relax the muscles around the knee and improves blood flow, which can make movement feel smoother.
6. Consider professional guidance: A physiotherapist can assess how your knee moves, identify any muscle imbalances or tracking problems, and give you a personalised strengthening plan. This is one of the most effective ways to address grinding that doesn’t resolve on its own.

Can a Knee Support Help?

Many people find that a well-fitted knee support or brace reduces discomfort and gives them more confidence to stay active. Here’s how they work mechanically.

Stability: A brace provides gentle external support around the knee, helping to keep the joint aligned during movement. This is especially useful if your grinding stems from mild instability or a tendency for the kneecap to drift to one side.

Compression: The snug fit improves blood flow and can help reduce swelling after activity. Many users also find it gives them a clearer sense of where their knee is in space — something that is technically called joint awareness — which helps them move more fluidly.

Heat retention: Some braces are designed to retain body heat around the joint. This warmth helps the muscles and tendons relax, which can reduce stiffness and make the knee feel less tight when you walk.

A knee support on its own is unlikely to resolve the issue completely, but it can be a useful part of a wider approach while you work on strengthening, adjusting activity, and addressing any underlying causes.

A Note on Our Knee Supports

At NuovaHealth, we offer a range of knee supports designed for everyday wear, with breathable material and adjustable straps so you can choose the level of compression that feels right for you. Whether you need a lightweight sleeve for walking or a more structured brace for sport, you’ll find an option that fits your lifestyle. If you think a knee support could help you, take a look at our selection below.

To bring it all together: if your knee grinds but doesn’t hurt, it’s usually just part of how your body works. Keep an eye out for the warning signs we’ve covered — if any appear, get it checked. And if you’re simply looking for ways to keep your knees happy, the practical steps above are a solid place to start. Look after your knees, and please get in touch again if you have any further questions.