Relationship between magnitude of resection, complication, and prosthetic survival after prosthetic knee reconstructions for distal femoral tumors

Background and Objectives: Limb-sparing surgery has become the preferred su rgical treatment of malignant bone tumors. The objective of this study was to evaluate factors that influence the morbidity and outcome of prosthetic knee replacement after resection of malignant tumors of the distal femur. Methods: Eighty-two patients who had a resection of malignant tumor of the distal femur and implantation of a segmental knee prosthesis (minimum follo w-up, 2 years) were retrospectively reviewed. Results: Twenty-nine patients (35%) underwent 32 prosthetic revisions, 6 fr om perioperative wound complications, 13 from aseptic loosening, and 13 fro m other complications. The 3-, 5-, and IO-year Kaplan-Meier prosthetic surv ival rates were 82%, 71%, and 50%, respectively. On univariate analysis, pa tients who had more than 40% resection of the distal femur (P = 0.010) and those who had all their vasti muscles resected (P = 0.011) had significantl y worse prosthetic survivals than the others. On multivariate analysis, res ection of more than 40% of the distal femur was a significant negative prog nostic factor for prosthetic survival (P = 0.017). Aseptic loosening was th e primary cause of late prosthetic failure. Differences in the magnitude of resection influenced prosthetic survivorship more than prosthetic design. Conclusions: In the distal femoral endoprosthetic replacement, higher short - and long-term complications were found after extensive resections. Asepti c loosening was the primary cause of prosthetic failure. (C) 1999 Wiley-Lis s, Inc.