This 27 year old man presented with a painful, stiff, swollen knee. Radiographs showed opacification of intra-articular cartilage and synovium (figure). He had sustained a gunshot wound to his knee several years earlier and a retained bullet is visible on the radiograph.  Lead arthropathy can present as a severe proliferative synovitis and progressive destructive arthritis. The earliest radiographic finding is fine punctate deposition of radio-opaque lead on articular cartilage similar to chondrocalcinosis but with increased density. Discrete lead speckling of hypertrophied synovium follows and eventually the articular cartilage and joint capsule may be completely outlined. Histopathological studies have confirmed synovial hypertrophy, diffuse chronic inflammation, and fibrosis with areas of haemosiderin deposition and calcification.1 Several interactive pathological processes may be involved, including mechanical trauma and chemical destruction.2

• Download figure
• Open in new tab
• Download powerpoint