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.
A Bakers cyst, or popliteal cyst, is a bulging lump behind your knee. Inside the lump is a sac filled with fluid. The cyst is caused by fluid buildup in your knee joint. This can happen if you have a knee injury, such as a cartilage tear. Osteoarthritis or rheumatoid arthritis can also cause an abnormal buildup of joint fluid. Common signs and symptoms: 1  A lump or swelling in the back of your knee when you stand or walk. 2  Knee swelling that goes away when you bend your knee. 3  Knee pain. 4  Stiffness or tightness in your knee that may get worse with movement.