Yes, knee cartilage can swell, although it doesn't swell in the same way that other tissues with a blood supply do.
Cartilage itself doesn't have blood vessels (avascular), so it relies on the surrounding synovial fluid and bone for nutrients and waste removal. Because of this, cartilage itself doesn't swell due to inflammation in the same way that muscle or skin might. However, when cartilage is damaged, it can lead to swelling around the knee joint. This swelling is typically due to an increase in synovial fluid, a condition known as an effusion.
Here's a breakdown:
- Cartilage Damage: Damage to the cartilage, such as a tear or degeneration, irritates the knee joint. This damage is frequently seen between the ages of 15 and 30 or above the age of 50.
- Inflammatory Response: The body responds to this irritation with an inflammatory response.
- Synovial Fluid Increase: The synovium, the lining of the joint, produces more synovial fluid in an attempt to lubricate the joint and remove debris. This excess fluid leads to swelling.
- Symptoms: This swelling contributes to other symptoms such as pain, stiffness, and limited range of motion. The knee might also feel "locked" or unstable.
- Long-term effects: Long term symptoms include osteoarthritis due to lack of the shock absorber function.
Causes of Cartilage Damage:
- Injury: A sudden impact or twisting motion can damage cartilage.
- Overuse: Repetitive stress can wear down cartilage over time.
- Osteoarthritis: This degenerative joint disease causes cartilage to break down.
In summary, while cartilage itself doesn't swell in the traditional sense, damage to it triggers an inflammatory response in the knee joint that leads to an increase in synovial fluid and subsequent swelling around the knee.
