Symptoms

Knee bursitis can be very painful. Other common symptoms include: 

  • Swelling 
  • Stiffness 
  • Achiness 
  • Pain with pressure (it hurts more when you press on it) 
  • Redness 
  • Puffiness 
  • Warmth 
  • Tenderness 
  • Discomfort while the knee is in use or at rest 

When to See a Doctor

The first sign of trouble with knee bursitis is pain. The bursa that is found over the kneecap can sometimes become infected. See your doctor as soon as possible if you have any of the above-mentioned symptoms. Symptoms of knee bursitis usually begin slowly and get worse as time passes. 

Causes

Knee bursitis happens when the bursa fills with extra fluid and becomes inflamed. This inflammation puts pressure on the nearby tissue and causes discomfort. 

Knee bursitis can be caused by joint overuse (at work or during recreation), by injury, like a sharp blow to the knee, or when a joint is put under pressure for a long time. 

Knee bursitis can also be caused by: 

  • Frequent stress or pressure, such as kneeling on a hard floor 
  • Bacterial infection 
  • Obesity 
  • Complications from arthritis 

You are also more likely to get bursitis at an older age, or if your occupation or hobbies involve frequent repetitive motion. 

Diagnosis & Tests, Treatments, & Prevention

Diagnosis & Tests

To diagnose bursitis, your doctor will usually perform a physical exam and may take a sample of the fluid inside the bursa to make sure it is not infected. This is called aspiration. Imaging tests may be recommended to confirm or rule out knee bursitis. 

  • X-ray uses radio waves to create pictures of your knee. It may reveal a problem with a bone or another medical condition. 
  • MRI (magnetic resonance imaging) uses magnets and radio waves to create a more detailed image of the tissues in your knee. It can show if the bursa is infected or if a problem with a tendon is the cause of your pain. 
  • Ultrasound uses sound waves to create images of the joint. It can show swelling or damage in the affected area.