Doctors Note Logo

Back

Published on: 5/6/2025

What Are the Common Causes of Knee Swelling?

Knee swelling can happen for many reasons such as injuries, arthritis, or infections. Often, problems with the knee joint's soft tissues or bones lead to swelling.

answer background

Explanation

Knee swelling is common and can arise from different causes. Some common reasons include:

  • Injury: When you hurt your knee, like twisting it or falling, you might tear a ligament or the meniscus (the cushioning tissue in your knee). This can cause blood and fluid to build up inside the joint, leading to swelling.
  • Arthritis: Osteoarthritis (wear and tear of the joint) or inflammatory arthritis like rheumatoid arthritis can inflame the knee. When the joint lining gets inflamed, excess fluid forms, causing the knee to swell.
  • Infections: Sometimes, bacteria can infect the knee joint, which is called septic arthritis. This type of inflammation usually comes with pain, redness, and warmth around the knee.
  • Other causes: Conditions like gout or pseudogout, which are caused by crystals forming in the joint, can also lead to swelling. Chronic knee problems might also stem from less obvious sources, as noted in clinical studies of adults and adolescents.

Overall, the underlying cause of knee swelling is important to identify so that the right treatment can be given. If you notice swelling in your knee, it is best to visit a healthcare provider to find out why and how to manage it.

(References)

  • Tan JB, Sim YXA, How CH, Loh SYJ. Generalised knee swelling in adults. Singapore Med J. 2022 Apr;63(4):187-191. doi: 10.11622/smedj.2022054. PMID: 35698425; PMCID: PMC9251264.

  • 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.

  • Das D, Sallomi DF, Howlett DC. A case of chronic knee pain and swelling. Br J Radiol. 2011 Jan;84(997):92-5. doi: 10.1259/bjr/24552351. PMID: 21172970; PMCID: PMC3473812.

Tell your friends about us.

We would love to help them too.

smily Shiba-inu looking

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?

AI Symptom Check

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.