30-year-old male patient with severe left knee pain. Concern for avascular necrosis in a sickle cell patient. MENISCI: The medial and lateral menisci are intact.ARTICULAR CARTILAGE AND BONE: The articular cartilage of all three compartments is intactLow marrow signal within the distal femoral and proximal tibial metadiaphyses is consistent with red marrow replacement. There is medullary high T1 and T2 signal within the distal femoral diaphysis, which extends proximally outside the field of view, which is consistent with infarcted bone. LIGAMENTS: The cruciate and collateral ligaments are intact. EXTENSOR MECHANISM: The extensor mechanism is intact.ADDITIONAL
1. Findings consistent with bone infarction within the femoral diaphysis. 2. Diffuse red marrow replacement consistent with sickle cell anemia.3. Intact structures within the knee. 