Pelvic insufficiency fractures after irradiation: diagnosis, management, and rehabilitation.

Insufficiency fractures of the pelvis are commonly overlooked as causes of severe hip and low back pain. Predisposing factors include postmenopausal osteoporosis, corticosteroids, and local irradiation. Differential diagnosis includes metastatic disease to bone. We present the case of a 65-year-old woman who had a two-month history of low back pain and left groin pain. Her medical history included osteoporosis and endometrial cancer that was treated with radiation therapy to the pelvis 1 year prior to presentation. Despite bed rest, analgesics, and therapeutic modalities, her pain remained intractable and prevented ambulation. Plain radiographs showed no fracture. Computed tomography (CT) and magnetic resonance imaging showed fractures of the pelvis but were suggestive of malignancy. CT-guided bone biopsy was consistent with radiation osteonecrosis. After diagnosis and continued therapy, the patient progressed to ambulation with moderate discomfort. Failure to diagnose insufficiency fractures could lead to further pelvic irradiation, compromising already weakened bones and causing prolonged disability.