MR imaging assessment of arthritis of the knee.

The magnetic resonance (MR) imaging presentations of arthritis of the knee are important for radiologists to recognize because these disorders are often clinically unsuspected. When they are known or clinically suspected, knowledge of imaging features allows for the confirmation and characterization of the extent of disease. This article reviews the fundamental MR imaging manifestations of rheumatologic disorders of the knee and their presentation in specific arthropathies.