What could be the reason for getting a strange sound in your knee joints similar to cracking of knuckles when you get up?

Crepitus is the medical term for the sound/sensation of cracking, popping, or grinding in the joints. It's a common occurrence that usually doesn't indicate a serious underlying medical problem, particularly if it isn't accompanied by pain, swelling, or loss of function.

When you get up, the sound is likely due to the movement of tendons and ligaments over the bony surfaces of your knee joint. This can create a popping or cracking sound as the tissues move against each other.

Other possible causes of knee joint sounds:

- Gas bubbles: When the pressure in your knee joint changes, for example when you stand up, it can cause gas bubbles in the synovial fluid (the lubricating fluid in the joint) to burst, creating a popping sound.

- Ligament snapping: The ligaments in your knee can sometimes snap or flick over the bony prominences of the joint as you move, producing a clicking sound.

- Meniscus movement: The menisci are C-shaped pieces of cartilage that act as shock absorbers in your knee. They can sometimes move slightly as you move your joint, creating a clicking sound.

- Osteoarthritis: In some cases, knee joint sounds can be a symptom of osteoarthritis (OA), a degenerative condition that causes the breakdown of the cartilage in the joint. OA can cause the bones in the joint to rub against each other, creating a grating or grinding sound.

If the sound in your knee joint is accompanied by any of the following, it's important to see a healthcare provider for evaluation:

- Pain

- Swelling

- Stiffness

- Loss of function

- Difficulty walking

- Redness or warmth around the joint