Infection of a knee joint is a very serious medical condition. A septic (infected) knee is most often caused by bacteria (such as staph or strep), but in rare instances can be caused by other microorganisms. Prompt diagnosis and treatment is essential in the native knee to avoid rapid destruction of the cartilage and bone in the knee.
When diagnosed early, septic knee treatment is usually arthroscopic irrigation and debridement. However, an open debridement may be required. Despite early diagnosis and treatment, joint destruction may still occur. Late effects of joint infection (septic arthritis) may require treatment with joint replacement as long as there is no persistent infection remaining within the knee.