Figure 1.

74 year-old man with prior left total knee arthroplasty and patellar revision with increasing pain, now with periprosthetic osteolysis and manifestations of metallosis. Lateral (Fig. 1a) and AP (Fig. 1b) radiographs of the left knee show areas of osteolysis (arrows #1 and #2 in both projections) with associated fracturing of the tibial plateau (arrow #3, lateral view). Several metallic debris fragments are evident (arrow #4, lateral view). Amorphous increased density is present posterior to the knee on the lateral view (*). Similar findings seen at the hip have been referred to as the “cloud sign” of metallosis. A joint effusion is present. Vascular calcifications are noted.