Diagnosis

Your doctor is likely to start with a detailed history and physical examination. After that you likely will need tests to determine the underlying problem that is causing your swollen knee.

Imaging tests

Imaging tests can help show where the problem is located. Options include:

  • X-ray. An X-ray can rule out broken or dislocated bones, and determine if you have arthritis.
  • Ultrasound. This test can check for arthritis or disorders affecting the tendons or ligaments.
  • MRI. This test can detect tendon, ligament and soft tissue injuries that aren't visible on X-rays.

Joint aspiration (arthrocentesis)

Your doctor withdraws fluid from inside your knee to check for the presence of:

  • Blood, which may stem from injuries or bleeding disorders
  • Bacteria, which may be causing an infection
  • Crystals common to gout or pseudogout

Treatment

Treatment varies, depending on the cause of the swollen knee, its severity and your medical history. Treatment generally involves pain medication and procedures to remove fluid from the knee joint.

Medications

Your doctor might prescribe oral pain medication, if over-the-counter pain relievers aren't enough. To ease inflammation, your doctor might suggest an oral corticosteroid, such as prednisone. Other types of steroids can be injected directly into your knee joint.

Surgical and other procedures

Treating the underlying cause of a swollen knee might require:

  • Arthrocentesis. Removing fluid from the knee can help relieve pressure on the joint. After aspirating joint fluid, your doctor might inject a corticosteroid into the joint to treat inflammation.
  • Arthroscopy. A lighted tube (arthroscope) is inserted through a small incision into your knee joint. Tools attached to the arthroscope can remove loose tissue or repair damage in your knee.
  • Joint replacement. If bearing weight on your knee joint becomes intolerable, you might need knee replacement surgery.

Your doctor might also recommend physical therapy to improve your knee's function and strength.

Lifestyle and home remedies

Taking care of yourself when you have a swollen knee includes:

  • Rest. Avoid weight-bearing activities as much as possible.
  • Ice and elevation. To control pain and swelling, apply ice to your knee for 15 to 20 minutes every two to four hours. When you ice your knee, raise your knee higher than the level of your heart, using pillows for comfort.
  • Pain relievers. Over-the-counter medicines such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) can help reduce your knee pain.

Preparing for your appointment

You are likely to be referred to a doctor specializing in musculoskeletal and joint problems.

What you can do

  • Write down your symptoms, and when they began.
  • Write down your key medical information, including other conditions.
  • Write down key personal information, including any major changes or stressors in your life.
  • Make a list of all your medications, vitamins or supplements.
  • Find out if anyone in your family has had an autoimmune disease.
  • Ask a relative or friend to accompany you, to help you remember what the doctor says.
  • Write down questions to ask your doctor.

Questions to ask your doctor

  • What's the most likely cause of my symptoms?
  • What kinds of tests do I need?
  • What treatments are available?
  • I have other health conditions. How can I best manage them together?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask other questions.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may leave time to go over points you want to discuss in depth. You may be asked:

  • Have you injured your knee recently? If so, describe the injury in detail.
  • Does your knee "lock" or feel unstable?
  • Has your knee felt warm or looked red? Do you have a fever?
  • Do you play recreational sports? If so, what sports?
  • Do you have any type of arthritis?
  • Do you have a family history of autoimmune disease?
April 21, 2018
References
  1. Beutler A, et al. Physical examination of the knee. http://www.uptodate.com/home. Accessed March 11, 2015.
  2. Anderson BC. General evaluation of the adult with knee pain. http://www.uptodate.com/home. Accessed March 11, 2015.
  3. Firestein GS, et al. Hip and knee pain. In: Kelley’s Textbook of Rheumatology. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. https://www.clinicalkey.com. Accessed March 11, 2015.
  4. Knee problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Knee_Problems/default.asp. Accessed March 11, 2015.
  5. Anderson BC. Meniscal injury of the knee. http://www.uptodate.com/home. Accessed March 11, 2015.
  6. Roberts WN. Joint aspiration or injection in adults: Technique and indications. http://www.uptodate.com/home. Accessed March 11, 2015.
  7. Bope ET, et al. Rheumatology and the musculoskeletal system. In: Conn’s Current Therapy. Philadelphia, Pa.: Saunders Elsevier; 2014. https://www.clinicalkey.com. Accessed March 11, 2015.
  8. DeLee JC, et al. Knee arthritis. In: DeLee & Drez’s Orthopaedic Sports Medicine: Principles and Practice. 4th ed. Philadelphia, Pa.: Saunders Elsevier; 2015. http://www.clinicalkey.com. Accessed March 11, 2015.
  9. Laskowski ER (expert opinion). Mayo Clinic, Rochester, Minn. March 13, 2015.