Pregnancy-related avascular necrosis
Pregnancy-related avascular necrosis is a common cause of femoral head avascular necrosis (AVN). Since the femoral head is deficient in blood supply, it is particularly vulnerable for AVN. The pathophysiology is thought to be due to venous stasis and increased intramedullary pressure. Radiographs usually detect the advanced stages of AVN (usually 3 or 4).
Classical features of femoral head AVN include:
- articular head irregularity/defect
- subchondral lucency (arrow)