SELECTED CASE A 61-year-old woman with a 4-year history of breast cancer and known metastatic bone disease presented with bilateral hip pain for 3 months. Roentgenograms of the left hip revealed a destructive lesion involving the inter-trochanteric region of the left proximal femur. The left femoral lesion measured approximately 2 by 3 cm and involved 60% of the cortex. Right hip roentgenograms demonstrated an acetabular lesion of unknown extent. Bone scan revealed no other lesions. The patient subsequently underwent irradiation of both hips with excellent pain relief on the left but continued symptoms on the right. Orthopedic consultation was requested to evaluate the patient's risk for pathological fracture on the left. Computed tomography (CT) of the pelvis demonstrated a pathological fracture of the right acetabulum. Since the patient was free of pain on the left hip, a cemented total-hip arthroplasty was performed on the right hip. The patient did well