Factors Affecting Nonunion of the Allograft-Host Junction :

Over the past 24 years, the authors have implanted >870 massive frozen cadaveric allografts mostly for the treatment of defects created by the resection of a bone tumor. Most of the grafts were obtained from the authors' institutional bone bank. The results show that only stage and type of graft affected outcome predictably. Specifically, grafts for a Stage 2 or Stage 3 tumor had a poorer outcome than those for Stages 0 and 1. The results for allograft arthrodeses were considerably poorer than osteoarticular, intercalary, and allograft plus prosthesis. The other major factors in results were complications--recurrence, infection, fracture, and nonunion--with the former 2 having a profound negative effect on outcome. After the first year of susceptibility to infection (10%) and the third year of increased risk of fracture (19%), the grafts become stable, and approximately 75% are retained by patients and are considered to be successful for >20 years after implantation. Osteoarthritis becomes a problem at approximately 6 years for osteoarticular grafts, and so far, 16% of the patients with distal femoral, proximal tibial, or proximal femoral grafts have required total joint replacements. Although the current results are adequate, they are imperfect, and research should be directed at improving the results.

Since 1971, the Orthopaedic Service at the Massachusetts General Hospital has treated 106 patients with malignant or aggressive bone tumors by wide resection and replacement with frozen cadaveric allograft. Sixty-one of these patients have been followed for over two years (mean, 4.5 years), allowing a comprehensive end-results analysis. In 45 patients, mostly with giant-cell tumors of chondrosarcomas, the resection involved the articular end of a long bone and the replacement not only included bone, but glycerolized (to prevent freezing injury) and articular cartilage. Ten of the segments were intercalary (bone alone) and six involved a combination of bone and metallic joint prosthesis. Patients were graded as excellent, good, fair, or failure, depending principally on functional capacity. End-results analysis in this group showed that five of the 61 patients had either a local recurrence (2) and/or distant metastases (3); in five additional patients the limb was amputated or the implant removed, primarily because of infection (total failure rate, 16.5%). Forty-five (73.8%) had successful transplants (graded excellent or good) and were able to live essentially normal lives. Six of the patients (10%) required a brace or cane but three of these patients were able to return to preoperative work activities. Although the operations were arduous and difficult, and despite a high infection rate (13%) and occasional pathologic fractures (10%), the results compare favorably with other techniques used to restore the skeleton following massive segmental resection. In long-term follow-up, the data suggest that if no complication ensue in the first two years, the results are generally quite good and the grafts show no evidence of progressive deterioration with time.