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