Insufficiency subchondral fracture of the femoral head.

The authors recently encountered a 65-year-old osteoporotic woman who had had intractable pain in the hip joint that was diagnosed clinically as osteonecrosis. She was treated by total hip replacement. Histopathologically, the most striking finding was the presence of a subchondral fracture with associated callus formation and granulation tissue along both sides of the fracture line. There was no evidence of antecedent osteonecrosis. This case was diagnosed histopathologically as insufficiency subchondral fracture of the femoral head. This is the first case report to substantiate the presence of insufficiency subchondral fracture of the femoral head by both gross and microscopic examination. Because the treatment and management of insufficiency subchondral fracture are entirely different from osteonecrosis, it is important to differentiate between these two conditions.