Knee bursitis is inflammation of a small fluid-filled sac (bursa) situated near your knee joint. Bursae reduce friction and cushion pressure points between your bones and the tendons, muscles and skin near your joints.
Any of the bursa in your knee can become inflamed, but knee bursitis most commonly occurs over the kneecap or on the inner side of your knee below the joint.
Knee bursitis causes pain and can limit your mobility. Treatment for knee bursitis often includes a combination of self-care practices and doctor-administered treatments to alleviate pain and inflammation.
Knee bursitis signs and symptoms vary, depending on which bursa is affected and what's causing the inflammation.
In general, the affected portion of your knee might feel warm, tender and swollen when you put pressure on it. You might also feel pain when you move or even at rest.
A sharp blow to the knee can cause symptoms to appear rapidly. But most cases of knee bursitis result from friction and irritation of the bursa that occurs in jobs that require a lot of kneeling on hard surfaces — so symptoms usually begin gradually and can worsen over time.
When to see a doctor
The bursa that lies over your kneecap can sometimes become infected. Call your doctor if you have a fever in addition to pain and swelling in your knee.
Knee bursitis can be caused by:
- Frequent and sustained pressure, such as from kneeling, especially on hard surfaces
- Overuse or strenuous activity
- A direct blow to your knee
- Bacterial infection of the bursa
- Complications from osteoarthritis, rheumatoid arthritis or gout in your knee
Knee bursitis is a common complaint, but your risk of developing this painful disorder can increase from:
- Prolonged kneeling. People who work on their knees for long periods — carpet layers, plumbers and gardeners — are at increased risk of knee bursitis.
- Participation in certain sports. Sports that result in direct blows or frequent falls on the knee — such as wrestling, football and volleyball — can increase your risk of knee bursitis. Runners can develop pain and inflammation in the pes anserine bursa, situated on the inner side of your knee below the joint.
- Obesity and osteoarthritis. Pes anserine bursitis, affecting the inner side of your knee below the joint, often occurs in obese women with osteoarthritis.
To avoid knee bursitis or prevent its recurrence:
- Wear kneepads. If you're working on your knees or participating in sports that put your knees at risk, use padding to cushion and protect your knees.
- Take breaks. If you're on your knees for a period of time, take regular breaks to stretch your legs and rest your knees.
- Avoid excessive squatting. Excessive or repetitious bending of your knees increases the force on your knee joints.
- Achieve and maintain a healthy weight. This can help take pressure off your knee joint.
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
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.
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.
Bursitis often improves over time, so treatment is usually aimed at symptom relief. However, depending on the cause of your knee bursitis and which bursa is infected, your doctor might recommend one or more treatment approaches.
If an infection has caused the knee bursitis, your doctor will prescribe a course of antibiotic treatment.
Your doctor might refer you to a physical therapist or specialist in sports medicine, who can help you improve flexibility and strengthen muscles. This therapy might alleviate pain and reduce your risk of recurring episodes of knee bursitis. Protective knee braces might help if you can't avoid kneeling, and compressive knee sleeves can help reduce swelling.
Surgical and other procedures
More-invasive treatments for knee bursitis treatment include:
- Corticosteroid injection. If the bursitis is persistent and not responding to basic treatments, your doctor might inject a corticosteroid drug into an affected bursa to reduce inflammation. The inflammation usually subsides rapidly, but you might have pain and swelling from the injection for a couple of days.
- Aspiration. Your doctor might aspirate a bursa to reduce excess fluid and treat inflammation. He or she will insert a needle into the affected bursa and draw fluid into the syringe. Aspiration might cause short-term pain and swelling, and you might need to wear a knee immobilizer for a short period after the injection to reduce the chance of recurrent swelling.
- Surgery. If you have severe chronic or recurrent bursitis and don't respond to other treatments, your doctor might recommend surgery to remove the bursa.
Lifestyle and home remedies
To ease pain and discomfort of knee bursitis:
- Rest your knee. Discontinue the activity that caused knee bursitis and avoid movements that worsen your pain.
- Take over-the-counter pain relievers. Short-term use of an anti-inflammatory drug, such as aspirin, ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve, others), can help relieve pain.
- Apply ice. Apply an ice pack to your knee for 20 minutes at a time several times a day until the pain goes away and your knee no longer feels warm to the touch.
- Apply compression. Use of a compressive wrap or knee sleeve can help reduce swelling.
- Elevate your knee. Prop your affected leg on pillows to help reduce swelling in your knee.
Preparing for an appointment
You might start by seeing your primary care provider, who might refer you to a doctor who specializes in other joint disorders (rheumatologist) or an orthopedic surgeon.
Here's information to help you get ready for your appointment.
What you can do
Make a list of:
- Your symptoms and when they began
- Key personal information, including major stresses and your and your family's medical history
- All medications, vitamins and other supplements you take, including doses
- Questions to ask your doctor
Take a family member or friend along, if possible, to help you remember the information you're given.
For knee bursitis, basic questions to ask your doctor include:
- What is the most likely cause of my symptoms?
- Are there other possible causes?
- What tests will I need?
- What treatment do you recommend?
- Will I need to limit my activities?
- Are there self-care measures I can try?
- Are there brochures or other printed material I can have? What websites do you recommend?
Don't hesitate to ask other questions.
What to expect from your doctor
Your doctor is likely to ask you questions, such as:
- Did your pain begin suddenly or gradually?
- What work or recreational activities do you do that might affect your knees?
- Does your pain occur or worsen when doing certain activities, such as kneeling or climbing stairs?
- Have you recently fallen, been in an accident or suffered a blow to your knee?
- What treatments have you tried at home?
- What effect did those treatments have?