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Click 74 year-old man with metallosis and metal-induced synovitis following total knee arthroplasty. Noncontrast CT of the left lower extremity dated 3/31/2006 (KVP 120; mA 80; ww/wl 2000/400; axial plane; slice thickness: 2.5 mm; GE Lightspeed 16 CT scanner). The patient is status post left total knee arthroplasty with femoral, tibial, and patellar components in place. There are multiple lytic foci within the distal femur and to a greater degree in the proximal tibia. Small metallic fragments are demonstrated within the proximal tibia lucencies (seen posteriorly). The tibial plateau cortex is also disrupted consistent with a fracture. There is a moderate sized joint effusion and a remote avulsion fracture of the lateral femoral condyle. Atherosclerosis is incidentally noted.

Click 74 year-old man with metallosis and metallosis and Metal-Induced Synovitis Following Total Knee Arthroplasty. Noncontrast CT of the left lower extremity dated 5/19/2008 (KVP 120; mA 310; ww/wl 2000/400; axial plane; slice thickness: 2.5 mm; GE Lightspeed 16 CT scanner). The patient is status post left total knee arthroplasty, with significant streak artifact from the hardware that limits evaluation of the surrounding soft tissues and bones. There are dense, predominately intra-articular calcifications, and fairly coarse calcification of the joint capsule itself surrounding a moderate to large effusion. A rim of hyperdense material is seen outlining the suprapatellar joint cavity (for example, on images 87-120), correlating with the ``metal-line sign`` described on the radiographs. Additionally, just medial to the patella within the joint, there is a metallic fragment that measures approximately 0.4 cm in size (seen on image 120). This is felt to correspond with the displaced marker for the patellar polyethylene liner. Atherosclerosis is incidentally noted.