The structural allograft composite in revision total knee arthroplasty

Options in revision total knee arthroplasty with massive bone loss include arthrodesis, custom total knee arthroplasty, amputation, and revision with structural allograft-prosthesis composites. Advantages of structural allografts include their biologic potential, versatility, relative cost-effectiveness, bone stock restoration, and potential for ligamentous reattachment. Disadvantages include the risk of disease transmission and graft nonunion, malunion, collapse, or resorption. Extensive preoperative planning is required to rule out infection and to select properly the type and size of allograft and prosthetic implant. Implant designs with diaphyseal-engaging stems and increased prosthetic constraint often are required. The host site and allograft require meticulous preparation to maximize surface contact and mechanical interlock of the allograft and host. Allograft fixation must be rigid to allow for incorporation. Ligamentous reattachment to the allograft is most successful when done by a bone block technique. Common complications include instability and graft collapse.