要約

• Common accumulation of synovial fluid that is usually the result of a knee joint abnormality, such as arthritis or a cartilage tear.
• May present with swelling or pain behind the knee, but most cases are asymptomatic.
• May rupture, leading to severe pain and calf swelling.
• Usually only conservative treatment is required.
• Large symptomatic cysts that do not resolve may require drainage.