Extraosseous manifestations of rheumatoid arthritis in the foot and ankle.

The immune mediated pathologic effects of rheumatoid arthritis on osteoarticular tissues are well delineated in the orthopaedic and medical literature. Less well explored are the extraosseous manifestations of rheumatoid arthritis. The rheumatoid disease process can affect virtually any organ system or tissue in the human body; from scleritis, arteritis, and splenomegaly to neuropathy, bursitis, and tendinopathy. The scope of this treatise is to define better for the clinician the extraosseous presentation of rheumatoid arthritis in the foot and ankle.