Paraarticular soft-tissue changes in infections and trauma of the lower extremity in children.

Evaluation of the paraarticular soft tissues is of primary importance in diagnosing acute joint problems of the lower extremity in children. With trauma, soft-tissue changes can alert the radiologist to an underlying bony injury; while with acute infection or inflammation, they enable identification and differentiation of the early stages of septic arthritis from osteomyelitis. Some soft-tissue changes have been described; others are presented for the first time. Becaiuse the findings differ from joint to joint, each joint is discussed separately.