SymptomsBy Mayo Clinic staff
Signs and symptoms of water on the knee typically include:
- Swelling. The flesh around your kneecap may puff up noticeably. This swelling is most apparent when you compare the affected knee to the normal one.
- Stiffness. When your knee joint contains excess fluid, you may not be able to bend or straighten your leg completely.
- Pain. Depending on the cause of the fluid buildup, the knee may be very painful — to the point that it's impossible to bear weight on it.
When to see a doctor
Seek prompt medical attention if:
- Self-care measures or prescribed medications don't relieve the pain and swelling
- One knee becomes red and feels warm to the touch as compared to your other knee
- LeBlond RF, et al. DeGowin's Diagnostic Examination. 9th ed. New York, N.Y.: The McGraw-Hill Companies; 2009. http://www.accessmedicine.com/content.aspx?aID=3656578. Accessed March 31, 2012.
- Marx JA, et al. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa.: Mosby Elsevier; 2010. http://www.mdconsult.com/books/about.do?about=true&eid=4-u1.0-B978-0-323-05472-0..X0001-1--TOP&isbn=978-0-323-05472-0&uniqId=230100505-57. Accessed March 31, 2012.
- Mathison DJ, et al. Approach to knee effusions. Pediatric Emergency Care. 2009;25:773.
- Knee problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Knee_Problems/knee_problems_ff.asp. Accessed March 31, 2012.
- Meininger AK, et al. Evaluation of the injured runner. Clinics in Sports Medicine. 2012;31:203.
- Bettencourt RB, et al. Arthrocentesis and therapeutic joint injection: An overview for the primary care physician. Primary Care. 2010;37:691.
- Chang-Miller A (expert opinion). Mayo Clinic, Scottsdale/Phoenix, Ariz. June 14, 2012.