Collagen is a natural protein component of the skin that acts like a scaffold and the main building block for cells, tissues and organs. About a third of the protein content in your body is made up of collagen, which is found in the bones, muscles, and tissues of the organs.
1 There can be the accumulation of fluid on the knee after an accident. 2  In most cases, the fluid is blood which can be through a fracture caused to the knee. 3  The swelling of the knee often takes place within some minutes of the injury occurring. 4  Gout and pseudo-gout can also cause fluid on the knee.
Fluid on the knee from an infection could be an accumulation of pus in your joint instead of synovial fluid. Your doctor can take a sample of the fluid in your knee and have it tested to see what is causing it.ymptoms. Symptoms of fluid on the knee due to arthritis include swelling and tenderness. If your knee is inflamed, swollen, red and hot when you touch it, you probably injured your knee or have an infection.