Diagnosis

Doctors often can make a diagnosis of knee bursitis with a medical history and physical exam. Your doctor will:

• Compare the condition of both knees, particularly if only one is painful
• Gently press on areas of your knee to detect warmth, swelling and the source of pain
• Inspect the skin over the tender area for redness or other signs of infection
• Carefully move your legs and knees to determine your knee's range of motion and whether it hurts to bend or flex it

Imaging tests

To help rule out injuries that can cause signs and symptoms similar to those of bursitis, your doctor might request one or more of the following imaging tests:

• X-ray. These can be useful in revealing a problem with a bone or arthritis.
• MRI. MRIs use radio waves and a strong magnetic field to produce detailed images of structures within your body. This technology visualizes soft tissues, such as bursae.
• Ultrasound. Using sound waves to produce images in real time, ultrasound can help your doctor better visualize swelling in the affected bursa.

Aspiration

If your doctor suspects that you have an infection or gout in the bursa, he or she might take a sample of the bursa fluid for testing by inserting a needle into the affected area and draining some of the fluid. This can also be used as treatment.