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Which joints are most often affected by septic arthritis?

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Septic arthritis is an acute inflammation of one or more joints caused by an infection. While the condition can affect multiple joints, it most frequently involves a single large joint, with the knee being the most common site.12

The infection typically occurs when microorganisms, most commonly Staphylococcus aureus, enter the joint space via the circulatory system, though it can also result from penetrating trauma or surgery. Because the resulting pus can erode articular cartilages, which have little capacity for regeneration, prompt medical treatment is essential to prevent permanent joint damage.21