Use of structural allograft in revision total knee arthroplasty in knees with severe tibial bone loss.

BACKGROUND: Tibial bone loss is frequently encountered at the time of revision total knee arthroplasty, and the outcome of the revision often depends on the management of this bone deficiency. We examined the clinical and radiographic outcomes of a series of revision total knee arthroplasties in which a structural allograft had been used to reconstruct a tibial bone defect encountered at the time of the revision procedure.

METHODS: From January 1985 through September 1999, one surgeon performed revision arthroplasty in forty-nine knees (forty-seven patients) with a severe tibial bone defect. The reasons for the revisions included polyethylene wear and osteolysis in twenty-four knees, aseptic loosening in seventeen knees, infection in five knees, and failure for another reason for three knees. Structural allograft was used alone in thirty-five knees and in conjunction with a tibial augment in fourteen knees. The mean age of the patients at the time of the revision arthroplasty with the allograft was sixty-seven years. The patients were assessed clinically with use of the Knee Society score and radiographically.

RESULTS: The status of the implant was known for forty-six of the forty-nine knees in this study. It was unknown for one patient (one knee) who was lost to follow-up and for two patients (two knees) who died less than five years postoperatively. Four revision procedures in four patients failed and required a reoperation. Two of the failures were due to infection. At a mean of ninety-seven months postoperatively, the mean Knee Society clinical score was 84 points for the knees that had not had a reoperation due to failure. The mean arc of motion improved from 87 degrees preoperatively to 103 degrees at the most recent follow-up evaluation. Histological evaluation of specimens retrieved at two autopsies demonstrated graft union to host bone.

CONCLUSIONS: A structural allograft provides a stable and durable reconstruction of a tibial bone deficiency. At a mean of ninety-five months postoperatively, we found no instance of graft collapse or aseptic loosening associated with the structural allograft. We recommend the use of a structural allograft for the management of severe tibial bone deficiency at the time of revision total knee arthroplasty.