To determine the most stable mode of internal fixation for the pathologic femoral shaft fracture with extensive cortical destruction, 2 fixation techniques incorporating methylmethacrylate were compared. Osteotomies through standardized cortical defects were created in intact embalmed femora to simulate a standard pathologic fracture. Fixation obtained with either intramedullary Schneider rods or 28-hold ASIF plates, both using bone cement, was compared in torsion and bending. In torsion, plate-fixed femora failed at a mean load of 71.2 newton-meters compared to 26.8 newton-meters for the Schneider rod counterparts. In bending, plate-fixed bones at a mean load of 8133.9 newtons compared to 1921.4 newtons for rod-fixed femora. Fixation with double plates and methylmethacrylate was clearly more stable and allowed for immediate pain-free ambulation.