Factors affecting nonunion of the allograft-host junction.

Nonunion of allograft-host junction after bone transplantation is not uncommon, and its treatment frequently is problematic. To improve the understanding of these nonunions, a retrospective review was performed of 163 nonunions in 945 patients who underwent allograft transplantation (17.3%) for various benign and malignant tumors at the authors' institution between 1974 and 1997. Of these 945 patients, 558 did not receive adjuvant therapy. Chemotherapy was administered to 354 patients and only 33 patients received radiation therapy alone. Seventy-one patients had radiation treatment and chemotherapy. Of the 163 patients who had nonunion develop at the allograft-host junction, there were 269 reoperations performed on the involved extremity. In 108 patients, treatment was successful resulting in union of the allograft-host junction. Forty-nine patients did not respond to multiple surgical treatment attempts. The greater the number of surgical procedures, the worse the outcome. The rate of nonunions increased to 27% for the patients who received chemotherapy as compared with 11% for the patients who did not receive chemotherapy. The order of allografts from highest rate of nonunion to lowest was as follows: alloarthrodesis, intercalary, osteoarticular, and alloprosthesis. Infection and fracture rates were higher in the patients with nonunions as compared with the patients without nonunions.