Swollen knee


Swollen knee occurs when fluid accumulates in or around the knee joint, causing it to enlarge. The cause of the swelling can be due to trauma, overuse injuries, or an underlying illness or condition can all cause knee to swell. To determine the reason for the swelling, a sample of the fluid may need to be tested for infection, illness, or blood from an injury. This condition may be referred as an effusion in the knee joint.
Everyday activities can put a lot of strain on the knees, which often bear the weight of the body. Treatment for the swelling can begin as soon as the underlying cause is identified and may involve removing some of the fluid to reduce discomfort and stiffness.


The following signs and symptoms of swollen knee includes:

  • Pain: The knee may be at severe pain, making it difficult for the patient to put any weight on it.
  • Swelling: When someone compares the affected knee to the other knee, the skin around the kneecap may appear visibly swollen.
  • Stiffness: Patient might not be able to bend or straighten their leg entirely if their knee joint is filled with fluid.

It is recommended to seek medical help if self-care techniques such as ice and rest do not relieve the symptoms. If one knee starts to become red and feel warmer to the touch than the other, get medical help as soon as possible that this could indicate a joint infection.


A swollen knee can be cause by a variety of issues, from traumatic injuries to illnesses.

  • Injuries: Any damage to the knee can result in excess joint fluid accumulation. The following injuries can lead to fluid accumulation in and around the knee joint:
    • Torn ligament of the anterior cruciate ligament (ACL)
    • Meniscus tear
    • Overuse
    • Fractures
  • Other diseases: The following underlying illnesses and disorders can cause fluid to accumulate in and around the knee joint:
    • Arthritis (0steoarthritis, rheumatoid arthritis, gouty arthritis)
    • Infection
    • Pseudogout
    • Bursitis
    • Cysts or tumors

Risk factors

The following factors increase the risk of a swollen knee includes:

  • Age: As the patient get older, there is a higher risk of getting a swollen knee due to arthritis.
  • Obesity: A swollen knee can result from excess weight placing additional strain on the knee joint, which also contributes to knee deterioration and tissue and joint overload.
  • Sports: The kinds of knee injuries that result in swelling are more common in those who participate in sports that require twisting the knee, like basketball or soccer.