Septic arthritis (SA) is a joint infection. The joint reacts to it by filling with pus. It may also become swollen.
Bacteria is the most common cause of this infection. Viruses and fungi can also cause infection.
The infection may be started by an organism:
Joint Damage in Knee
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This problem is more common in older adults. Things that may raise the risk in adults are:
This problem is also more common in children who are male and those who are under 3 years old. Things that may raise the risk in children are:
The knee, hip, shoulder, ankle, elbow, and wrist are the most common sites in adults. Problems may be:
The knee and hip are the most common sites for SA in children. Problems may be:
You will be asked about you or your child’s symptoms and health history. A physical exam will be done. Your doctor may refer you to a specialist.
Tests may be done to look for signs of infection. This can be done with:
Images of the area may be taken. This can be done with:
The goal is to treat the infection. This is done with antibiotics.
Fluid may be removed to ease pressure in the joint. This may be done with a needle or through surgery.
There are no known guidelines to prevent this problem.
National Institute of Arthritis and Musculoskeletal and Skin Diseases
The Arthritis Society
Ross JJ. Septic Arthritis of Native Joints. Infect Dis Clin North Am. 2017 Jun;31(2):203-218.
Septic arthritis. Patient UK website. Available at:
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Accessed September 25, 2020.
Septic arthritis in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/septic-arthritis-in-adults. Accessed September 25, 2020.
Septic arthritis in children. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/septic-arthritis-in-children. Accessed September 25, 2020.
Last reviewed September 2020 by
EBSCO Medical Review Board
Warren A. Bodine, DO, CAQSM
Last Updated: 6/8/2021