Background: In the management of a resected distal femoral or
proximal tibial condyle as the result of tumor or trauma, a unicondylar
osteoarticular allograft is currently the only reconstructive option that
avoids the sacrifice of the unaffected condyle. The purposes of this study
were to perform a survival analysis of unicondylar osteoarticular allografts
of the knee and to evaluate the complications.
Methods: We retrospectively reviewed the results of forty large
unicondylar osteoarticular allograft procedures in thirty-eight patients who
were followed for a mean of eleven years. Twenty-nine allografts were femoral
transplants and included eleven medial and eighteen lateral femoral condyles.
Eleven allografts were tibial transplants, including four medial and seven
lateral tibial condyles. The procedure was performed after a tumor resection
in thirty-six patients and to replace condylar loss after a severe open
fracture in the remaining two patients. Complications were analyzed, and
allograft survival from the date of implantation to the date of revision or
the time of the latest follow-up was determined. Functional and radiographic
results were documented according to the Musculoskeletal Tumor Society scoring
system at the time of the latest follow-up.
Results: One patient died of tumor-related causes without allograft
failure before the two-year follow-up evaluation. The global rate of allograft
survival at both five and ten years was 85%, with a mean follow-up of 148
months. In six patients, the allografts were removed at an average of
twenty-six months (range, six to forty-eight months) and these were considered
failures. All six patients underwent a second allograft procedure including
two new unicondylar and four bicondylar reconstructions. The mean radiographic
score for the thirty-three surviving allografts evaluated was 89%, with an
average functional score of 27 of a possible 30 points.
Conclusions: Unicondylar osteoarticular allografts of the knee
appear to be a reliable alternative for patients in whom reconstruction of
massive osteoarticular bone loss is limited to one condyle of the femur or the
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.