When you bend down by the sofa to pick up that stray TV remote, what happens?
If you’re like many people, the answer may involve a soft clicking or cracking noise as your knees head south towards the carpet pile.
Doctors have a name for this. We call it crepitus, or sometimes crepitation. But what’s actually causing the noise? And should you ever be concerned about it?
What is that clicking sound?
The name crepitus is actually descriptive: it comes from the Latin word “crepare”, meaning rattle or creak. But the sound can vary from person to person. Some people get a soft popping or creaking noise. For others, it’s a rattle or grating sound. For still others, it’s a quite audible crack.
The noise is usually caused by tiny air bubbles accumulating in the synovial fluid, the thick liquid that helps our bones glide smoothly together within joints. As you bend or flex your knee, the bubbles come under pressure and suddenly burst (we have a medical name for this too: “cavitation”!). Result: a snap, crackle or popping noise from the joint.
Should you be concerned about it?
Most of the time, crepitus is harmless. In fact, it’s probably fair to say most of us experience it in some form. It’s certainly a very common area of questions here at Chris Bailey Orthopaedics. So, on one level, you could say crepitus is a normal part of having joints and bones. A likely follow-up question from us would be: are you experiencing any pain (or swelling) as well? If the answer is no, then it’s unlikely to be a cause for concern. If the answer is yes, we may want to investigate further.
So what else might be causing it?
As mentioned, crepitus isn’t a condition in itself; it’s simply a description. But it can be an indicator – in other words, a symptom – of something pathological inside the joint. Here are some possibilities:
Meniscus tear – if you damage one of the shock-absorbing pads of cartilage in your knee
Loose bodies – when fragments of cartilage break off and float freely or become trapped in the joint
Baker’s Cyst – if a cyst at the back of the knee puts pressure on the surrounding bones and tissues
Maltracking – if the bones in your joint don’t align properly, putting more pressure on one side
Could arthritis be involved?
It’s possible. Osteoarthritis is where the joint bones lose their protective layer of cartilage, usually through wear and tear, though sometimes after an injury. Without cartilage, the bone endings can grind against each other. As the surfaces become less smooth, they can cause audible crackling and popping sounds. But arthritis only becomes a real problem when the symptoms go beyond crepitus – if you’re getting things like swelling, inflammation, mobility issues, and of course pain.
Should I do anything about it?
The key thing to remember is that crepitus happens to most people. And in most cases, it doesn’t mean a serious knee problem. Nor will it inevitably get worse over time. Painless crepitus is rarely a reason to stop doing sport or other activities that keep you fit and healthy; even the occasional young athlete has very noisy knees! That said, it’s always good to be alert to other symptoms. If you have pain, swelling or a loss of normal motion in your joint alongside the crepitus, you may need to get your knee properly checked out. There are lots of things we can do to diagnose and treat issues in your knee, and some of the solutions may be as simple as physiotherapy and specific exercises. Whatever happens, we’ll help you find a way to manage it.