Imaging of Knee Swelling in Children

The knee joint is the largest joint in the body and comprises the tibiofemoral (medial and lateral) and the patellofemoral compartments. The knee joint is a modified hinge joint and relies on several associated muscles, tendons, and ligaments to provide strength and stability during movement and at rest. A limping child with a swollen knee is a common presentation encountered by pediatricians. Although trauma is the most common cause of pediatric knee swelling, a wide variety of pathologies can manifest as a swollen and/or painful knee joint in children, reflecting underlying abnormalities of soft tissue or osseous components of the knee.1,2 In the absence of a recent or remote history of knee trauma, other pathologic causes of knee swelling include infections and inflammatory conditions, congenital/developmental causes, vascular abnormalities, and neoplastic disorders.