Examination and diagnosis
Knee edema may indicate the presence of other knee conditions, usually arthritis, infection or injury. Your doctor will make an appointment to do some of the following tests to determine the cause
Imaging tests
These tests can show what is going on inside the knee joint. These tests can help determine whether the fluid is inside the joint or in the bursa, and can help determine the cause of the fluid build-up.
1. X-rays. Your doctor will order an x-ray to rule out a fracture or dislocation and to determine if you have arthritis.
2.Ultrasound. A noninvasive imaging test, ultrasound is widely used in Europe and is increasingly preferred in the United States to evaluate joint pain and swelling. Ultrasound is less expensive than MRI. Ultrasound can be used to diagnose arthritis or tendon/ligament disease.
3. Magnetic resonance imaging (MRI). If the cause of the swelling in your knee cannot be determined based on your medical history, physical examination, and X-rays, you may need an MRI. This test can detect tendon and ligament damage that is not visible on X-rays.
Blood tests
A blood sample taken from the arm can be used to detect.
1. infection.
2. inflammatory diseases.
3. rheumatoid arthritis.
4. Lyme disease.
5, bleeding disorders.
6, Gout.
Joint aspiration (arthrocentesis)
In this test, the doctor draws fluid from the knee joint to check for the presence of
1. bleeding from an injury or bleeding disorder.
2. bacteria causing an infection.
3. crystal deposits commonly found in the joints of patients with gout or pseudogout.
Arthroscopy
An orthopedic surgeon will insert a thin tube (arthroscope) with a magnifying lens and illuminating light through a small incision in the knee joint to examine the inside of the knee joint.