The article "Baker's Cyst" was published in the New England Journal of Medicine, Volume 394, Number 5, Page 497, on January 29, 2026. Baker's cyst is associated with knee joint diseases such as rheumatoid arthritis in the elderly. When knee joints are affected, synovial fluid can leak from the joint into the popliteal bursa and form a Baker's cyst. Rupture of the cyst leads to the emptying of the contents between the calf muscles, which causes painful swelling. This swelling can be confused with phlebothrombosis. In the diagnosis of venous diseases of the lower limbs, Baker's cyst is considered as another pathology in the vicinity of vascular structures during duplex ultrasound examination.