Subchondral insufficiency fracture of the femoral head and acetabulum : a case report.

Abstract

Subchondral insufficiency fracture of the femoral head generally occurs in elderly patients, who tend to have osteopenic bone and/or to be overweight. It characteristically presents as acute pain in the hip without obvious antecedent trauma1. Some subchondral insufficiency fractures of the femoral head resolve spontaneously2,3, but several have shown progressive collapse requiring surgical intervention1. Findings on magnetic resonance imaging are characterized by a subchondral linear or serpiginous pattern of very low signal intensity on T1-weighted images with an associated bone-marrow edema pattern. This subchondral low-intensity band has been shown histologically to be a fracture line4. In a recent study, eleven subchondral insufficiency fractures of the femoral head were associated with rapid destruction of the hip joint similar to that seen in rapidly destructive arthrosis of the hip joint5. The prognosis for subchondral insufficiency fractures of the femoral head thus remains unclear. Previous investigators have examined histological specimens obtained from the femoral head1-5. We describe a case of an early-stage subchondral insufficiency fracture in which histological sections were obtained from both the femoral head and the acetabulum. We found a subchondral fracture on the acetabular side as well as in the femoral head. A sixty-four-year-old woman had a sudden onset of severe pain in the right hip when she bent to pick up something from the floor. The pain persisted, even at night, and a limp developed. There was no history of steroid therapy or alcoholism. The patient's height was 157 cm, she weighed 82 kg, and the body mass index (33.3) indicated obesity. On examination, the range of motion of the right hip was slightly limited (115° of flexion, 40° of abduction, 20° of adduction, 15° of external rotation, and 20° of internal rotation). …