Insights from imaging on the epidemiology and pathophysiology of osteoarthritis.

This article highlights recent studies, particularly those with an emphasis on MR imaging, that are providing unique insights into the relation between structures identified on imaging and symptoms and disease genesis. It is becoming increasingly apparent that the subchondral bone, periosteum, periarticular ligaments, periarticular muscle spasm, synovium, and joint capsule are all richly innervated and are the likely source of nociception in osteoarthritis. It is also apparent that local tissue alterations in the bone and meniscus and alignment of the lower extremity are important in terms of disease genesis. This article represents the literature in that much of the focus and understanding is knee centric with less focus on the hip and hand.