What Are the Visual Signs of a Swollen Knee?

Reviewed by Garrett Kneese, MD, MPH

Family Medicine

A swollen knee can look puffy and bigger than usual with a bulging outline. It may also have a stretched, shiny appearance around the joint. You should see a doctor immediately if you have this symptom as it may be due to an infection in the knee.

Explanation

When a knee is swollen, doctors often see that the knee looks puffed up and bigger compared to a normal knee. This puffiness happens because extra fluid builds up inside the joint. You might notice that the area around the kneecap or the upper part of your knee looks fuller and more rounded. Sometimes the skin over the swollen part can appear stretched and shiny because it is being pushed out from the extra liquid. In some cases, the swollen knee may also show uneven contours, meaning one part of the knee looks more bulged than another. It is important to remember that people might feel that their knee is swollen even if it does not look very swollen to others. This difference between what you feel and what is seen is something that has been noticed in research. Look for a knee that appears larger than the other, with a noticeable bulge especially in the soft tissue areas, to identify visual signs of swelling.

(References)

Tanaka S, Nishigami T, Ohishi K, Nishikawa K, Wand BM, Stanton TR, Yamashita H, Mibu A, Tokunaga M, Yoshimoto T, Ushida T. "But it feels swollen!": the frequency and clinical characteristics of people with knee osteoarthritis who report subjective knee swelling in the absence of objective swelling. Pain Rep. 2021 Nov 8;6(4):e971. doi: 10.1097/PR9.0000000000000971. PMID: 34765853; PMCID: PMC8577815.
Mistovich RJ, O'Toole PO, Chauvin NA, Wilkins BJ, Ganley TJ. Left knee pain and bilateral knee swelling in an adolescent. Clin Orthop Relat Res. 2014 Nov;472(11):3591-8. doi: 10.1007/s11999-014-3883-4. Epub 2014 Aug 28. PMID: 25163688; PMCID: PMC4182385.
Elsawy NA, Ibrahiem AH, Younis GA, Meheissen MA, Abdel-Fattah YH. Clinical examination, ultrasound assessment and aspiration of knee effusion in primary knee osteoarthritis patients. J Orthop Surg Res. 2023 Jun 10;18(1):422. doi: 10.1186/s13018-023-03891-6. PMID: 37301888; PMCID: PMC10257372.

Tell your friends about us.

We would love to help them too.

For First Time Users

What is Ubie’s Doctor’s Note?

We provide a database of explanations from real doctors on a range of medical topics. Get started by exploring our library of questions and topics you want to learn more about.

Learn more about symptoms

Knee pain

Not sure about the cause of your current symptoms?

Try our AI-based symptom checker

With an easy 3-min questionnaire, you can get a free AI-powered report on possible causes

Tips to try:

Provide specific, detailed info about all symptoms you have.
Give accurate information about yourself including current conditions.
Answer all follow-up questions

Purpose and positioning of servicesUbie Doctor’s Note is a service for informational purposes. The provision of information by physicians, medical professionals, etc. is not a medical treatment. If medical treatment is required, please consult your doctor or medical institution. We strive to provide reliable and accurate information, but we do not guarantee the completeness of the content. If you find any errors in the information, please contact us.