Nat. Rev. Rheumatol. doi:10.1038/nrrheum.2016.148 Figure 2 Correlation of radiographic and structural changes in osteoarthritis Figure 2 | Correlation of radiographic and structural changes in osteoarthritis. The radiographic features of advanced osteoarthritis (OA) include joint-space narrowing, subchondral bone sclerosis, the formation of osteophytes at the joint margins, and flattening and deformation of the subchondral cortical plate referred to as bone attrition. Synovitis, which is often present, cannot be detected with standard radiographs. The loss of joint space results from the loss of articular cartilage, which can be asymmetrical in the knee joint, affecting principally the medial or lateral side. Thickening of the subchondral cortical plate accounts for the appearance of bone sclerosis. Radiograph image courtesy of Douglas M. Mintz, Hospital for Special Surgery, Department of Radiology, New York, New York, USA. Radiograph image courtesy of Douglas M. Mintz, Hospital for Special Surgery, Department of Radiology, New York, New York, USA. Goldring, S. R. & Goldring, M. B. (2016) Changes in the osteochondral unit during osteoarthritis: structure, function and cartilage–bone crosstalk Nat. Rev. Rheumatol. doi:10.1038/nrrheum.2016.148