Structural allografting in revision total knee arthroplasty.

Between 1985 and 1991, 15 patients underwent structural allografting as part of revision total knee arthroplasty. All patients had large segmental, cavitary, or combination defects of the femur and/or tibia. Seven distal femurs and 12 proximal tibias required allografting. Patients were evaluated with physical examination, radiographs, and The Hospital for Special Surgery knee rating scale. Three patients died, leaving 15 allografts for follow-up study. The average age at surgery was 63 years. The follow-up period averaged 47 months (range, 30-101 months). Average range of motion before surgery was 4 degrees to 93 degrees, and after surgery, 2 degrees to 104 degrees. Average knee score was 47 before and 86 after surgery. Preoperative alignment averaged 5 degrees varus, ranging from 25 degrees valgus to 20 degrees varus, and postoperative alignment averaged 4 degrees valgus, ranging from neutral to 6 degrees valgus. All patients, except one, had improvement of pain and stability. All of the 15 allografts healed to host-bone and 13 showed evidence of incorporation. There were no infections or fractures of the allografts. One complication directly related to the allograft occurred; that patient had a tibial component fracture over a proximal tibial allograft 3 years after surgery. Three other complications occurred. One was tibial loosening in a patient who received a distal femoral allograft, the second was a proximal tibial fracture in a patient who received a distal femoral allograft, and the third was an intraoperative patellar tendon avulsion. These results suggest that structural allografting can provide a satisfactory method of managing large bone defects in the failed total knee arthroplasty.