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