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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 tibia. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: “Unicondylar Osteoarticular Allografts of the Knee” (2007;89:2137-42).

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 tibia. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: “Unicondylar Osteoarticular Allografts of the Knee” (2007;89:2137-42).

The surgical risk and complication rates for an open excision of a benign osteochondroma have been reported as high as 13%. The advent of minimally invasive techniques allows a surgical resection with a smaller incision and a potential for less postoperative morbidity. We presumed endoscopic resection of symptomatic osteochondroma of the distal femur would decrease postoperative morbidity of open surgery and improve functional outcome. We performed endoscopic resection of a symptomatic osteochondroma in seven patients among 24 who had surgical excision. Preoperative studies include radiographs and computed tomography scans. At a mean followup of 33 months, patients were functionally evaluated according to the Lysholm score and the International Knee Documentation Committee scale. Four exostoses were located at the anterolateral femoral cortex, one at the trochlea, and two at the anteromedial cortex. Histologic diagnosis of an osteochondroma was confirmed in all cases. The average Lysholm score improved 22 points from a mean of 74 preoperatively to 96 postoperatively, and according to the International Knee Documentation Committee scale, all patients showed a normal knee. In 7 of 24 patients with a symptomatic osteochondroma of the distal femur close to the knee, we performed endoscopic resection with low morbidity and prompt functional recovery.

Reconstruction of extensor mechanism after proximal tibia tumor resection is a major concern, especially in young and physically active patients. We evaluated patellar tendon host- donor reattachments in 42 consecutive proximal tibia allo- graft reconstructions after bone tumor resection to determine if patellar tendon length and integrity was maintained, and if active knee extension and adequate function was achieved. Patellar tendon length was radiographically measured in all patients by the Insall-Salvati index while magnetic resonance was available in 19 patients to evaluate imaging integrity. Eight patients were not available for functional assessment, leaving 34 patients for clinical evaluation with the Musculoskeletal Tumor Society scoring system. According to the Insall-Salvati index evaluation, the reconstructed patellar tendon remained stable with no elongation between preoperative and postoperative measurements (1.15 versus 1.13). Postoperative magnetic resonance images showed a continuous patellar host-donor tendon in all. Active knee extension was restored in all functionally evaluated patients with an average functional score of 26.6 points. Twenty-four patients had no extensor lag, while ten had an average residual extensor lag of 6.5°. Our findings suggest patellar tendon reconstruction with allogeneic tissue from the proximal tibia allograft sutured to the recipient's remnant patellar tendon can restore and stabilize active knee extension. Level of Evidence: Therapeutic study, level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Intercalary femur and tibia segmental allografts were implanted in 59 consecutive patients after segmental resection-52 for malignant and seven for benign aggressive bone tumors. The patients were followed up for an average of 5 years. Allograft survival was determined with the Kaplan-Meier method. Infection, fracture, and nonunion rates were determined. The overall 5-year survivorship for the 59 intercalary allografts was 79%, and we found no significant differences between allograft survival in patients receiving or not receiving adjuvant chemotherapy. Infection and fracture rates were 5% and 7% respectively. From 118 host-donor junctions, 11 did not initially heal (9%). The nonunion rate (10 of 69 osteotomies) for diaphyseal junctions was higher than the rate (one of 49 osteotomies) for metaphyseal junctions. Although some patients required reoperations because of allograft complications, it seems that the use of intercalary allograft clearly has a place in the reconstruction of a segmental defect created by the resection of a tumor in the diaphyseal and /or metaphyseal portion of the femur or tibia.