Massive bone defects are challenging problems in revision knee surgery. When defects are large and uncontained (without a cortical rim), structural allografts may be used to provide support for femoral and tibial components. This study reviewed 68 structural allografts at a mean of 5.4 years for clinical and radiographic outcomes. Indications for grafts included periprosthetic fracture in 19 knees, aseptic loosening in 29, infection in 11 and instability in 2. Seven knees had both femoral and tibial allografts. Multiple implant designs were used including 7 hinged prostheses. Thirteen knees (13/61) failed due to graft related complications including one graft nonunion, three aseptic loosenings, three periprosthetic fractures, four infections, and two for instability. The case of graft nonunion was successfully treated with revision fixation and autologous bone graft. There were three cases of graft resorption, two graded as severe and one as moderate. These results are satisfactory given the nature and complexity of the problem, however, reconstructive procedures require careful preoperative preparation and extensive experience in complex knee arthroplasty.
Level of Evidence: Therapeutic study, level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.