43-year-old woman with history of SLE presents with right knee pain. Evaluate for avascular necrosis of the distal femur and proximal tibia. MENISCI: There is slight blunting of the posterior horn of the lateral meniscus, consistent with a tear. The medial meniscus is normal in appearance. ARTICULAR CARTILAGE AND BONE: There is geographic signal abnormality in the distal femoral metaphysis, which features serpiginous signal abnormality, representing bone infarction. Additionally, there is a small region of infarct within the medial condyle of the femur, posteriorly. There are no defects of the articular cartilage of the knee. LIGAMENTS: No significant abnormality noted. EXTENSOR MECHANISM: No significant abnormality noted.ADDITIONAL
Bone infarction of the distal femur as described above. 