Insufficiency fracture of the acetabular medial wall.

Acetabular insufficiency fractures are much less common than acetabular fractures associated with trauma. They most commonly occur in postmenopausal women with a history of rheumatoid arthritis or pelvic irradiation. We present the case of a 93-year-old man with an atraumatic pelvic insufficiency fracture of the fossa acetabuli. The patient had 2 predisposing risk factors: osteoporosis and lower-extremity reconstructive surgery.