Presentation
35-year-old female patient diagnosed rheumatoid arthritis on corticosteroids for several years with the recent onset of severe knee pain of few weeks duration.
Patient Data
The lateral femoral condyle is showing a geographical subcortical margined area of alternating signal
intensity lesion displays low signal in T1WI with high signal peripheral signal and a central signal void area in STIR WI.
Case Discussion
MR picture of spontaneous osteonecrosis of the knee.
Previously spontaneous osteonecrosis of the knee was considered a primary osteonecrosis with no related cause, but now the presumed etiology is being an insufficiency fracture of the subchondral bone. SONK is seen more frequently in women with osteoporosis and of older age.