Symptoms

• Some of the signs and symptoms of excessive fluid building up on the knee are stiffness, bruising, pain and swelling. When the knee feels stiff, too much fluid on the knee means the range of motion is impaired. If you notice bruising on your knee, putting weight on it can be unbearable and fluid builds up as a result. Pain is usually associated with osteoarthritis, but can also be attributed to an injury or overuse. Swelling or puffiness also occurs when your knee contains too much fluid.
  
  

Trauma

• Some of the traumatic injuries that can cause fluid to build up include broken or fractured bones, overuse injuries and ligament or meniscus tears.
  
  

Osteorarthritis and Other Causes

• Osteoarthritis is he most common cause of excessive fluid buildup. Osteoarthritis sets in when the joint cartilage breaks down. Other reasons for fluid to build up are infection, gout, rheumatoid arthritis, cysts, tumors or kneecap bursitis.
  
  

Osteoarthritis Treatment

• Treatment for too much fluid on the knee centers on treating the primary disease or injury. If the problem is osteoarthritis, a doctor will probably aspirate the joint fluid or inject a corticosteroid into the joint to help relieve the inflammation, according to the Mayo Clinic.
  
  

Treating Other Causes

• If gout or pseudogout is the problem, one of several treatments can be used including an intra-articular corticosteroid injection or nonsteroidal anti-inflammatory drugs. For an infection, the doctor will prescribe antibiotics or aspirate of the knee. Arthroscopic knee surgery may also be a course of action if the doctor thinks there's damage inside the knee. And in severe cases, joint replacement can be an option.