Fracture of the femoral shaft occurring after total hip or total knee replacement is a rare but serious complication [1-29,31-37,39-49,52-54]. If the prosthesis is loose, the logical treatment is a revision operation with insertion of a femoral component with a longer stem to stabilize the fracture. If the stem is firmly fixed, the best method of treatment is more difficult to determine. The options available include closed treatment (traction or application of a spica cast or a cast-brace), exchange of the stem for a longer one that stabilizes the fracture, supracondylar nailing for a fracture proximal to a total knee prosthesis, and open reduction and internal fixation of the fracture. Closed treatment of a fracture of the femoral shaft is associated with many problems [3,5,11,14,15,20,25,29,31,35,48], including medical complications secondary to prolonged bed rest, potential loss of motion of the hip or knee, and non-union or malunion. Malunion is particularly troubling when it is associated with a total hip or knee prosthesis. Malalignment of the femur can accelerate loosening of the implant. Also, revision of a femoral component in the presence of a deformed femur is much more difficult. Exchange of a component that is well fixed (with either cement or bone ingrowth) for a component with a longer stem to stabilize the fracture not only is arduous but also can severely damage the surrounding bone. Anatomical alignment, union of the fracture, and a short recovery time are more likely if the stem is left intact and the fracture is treated with open reduction and internal fixation. The patient is positioned on his or her side on a conventional operating table. The fracture is exposed, reduced, and temporarily stabilized with cerclage wires or cables (Figure 1(A and B)). An ipsilateral allograft femur, split into two equal pieces at the linea aspera, is used to provide biological bone plates (Figure 2). A tibia, split into two equal pieces, can be used instead, but it will not fit the host femur as well. Our experience is with fresh-frozen allografts: however, it is possible that freeze-dried allografts would also work. It is important that the femur or tibia be split into two equal parts. Use of three smaller struts from one bone have not consistently proved to be rigid enough to provide fixation [8]. The inside surfaces of the grafts should be contoured to match the outside dimensions of the recipient femur (Figure 3). The two grafts are placed medial and lateral to the linea aspera, without disrupting it, in an effort to preserve its blood supply to the host bone (Figure 4). The struts should extend at least ten centimeters proximal and distal to the fracture to allow fixation on each side of the fracture with at least four wires. Fixation of the grafts to the femur can be achieved with number-16 cerclage wires or with 2.0-millimeter cables placed at two-to-four-centimeter intervals. Our current preference is to use hose clamps (from a hardware store), after they are sterilized, to compress the struts to the host bone initially and then to use double number-16 stainless-steel wires that are tightened and twisted with a Harris wire-tightener (Johnson and Johnson, Raynham, Massachusetts); the hose clamps are removed once the wires are secure (<a href='javascript:void(0);' class='custom-xref xref-F5-20' onclick = 'document.getElementsByClassName('F5-20')[0].scrollIntoView();window.