Both cemented and noncemented techniques have been used for total hip arthroplasty (THA). Each technique has advantages and disadvantages. Among the disadvantages of cemented THA are several perioperative complications, such as intraoperative cardiac or respiratory failure and hypotension, called "cement implantation syndrome," and extrusion of cement beyond the confines of the medullary canal. Cement extrusion can be the result of overreaming of the femoral canal and cortical perforation. This is a worrisome finding, as the risk of subsequent femoral fracture at the site of perforation is increased. Extruded cement, however, does not always indicate a problem. Extruded cement located within the femoral venous system, intravenous methylmethacrylate, for example, is not associated with long-term complications. While uncommon, it is important to differentiate this finding from the more serious cortical perforation. We report four examples of intravenous methylmethacrylate following THA and describe the imaging features that allow differentiation of this entity from the more significant finding of cortical perforation.