Efectividad de la aloprótesis para tumores óseos malignos de rodilla. Comparación entre la localización en fémur distal y tibia proximal

Resumen

Background: Malignant tumors located in the knee are infrequent, but they have high aggressiveness and severe prognosis. Medical advances, such as chemotherapy and radiotherapy, together with modern surgical techniques, have saved the limb and increased survival, although it is still relatively short. Allograft-prosthetic composite is one option for joint reconstruction after bone resection, which combines the advantages of the allograft and the prosthesis, theoretically. Previous studies reported good functional results of the allograft-prosthetic composite but also an unacceptable rate of mechanical and septic failures associated, among others, with the use of allografts sterilized with gamma radiation. For tumors of the distal femur, the fresh allograft has given good results in the osseous union of the host-allograft junction, however, the use of allograft-prosthetic composite for tumors of the distal femur has been scarcely published. The objective of the present study was to assess the effectiveness of allograft-prosthetic composite in malignant bone tumors of the distal femur and to compare the mechanical and clinical results with those of the proximal tibia. Methods: Forty-five patients, 24 patients with tumor affectation of the distal femur and 21 patients with tumor affectation of the proximal tibia were operated with allograft-prosthetic composite (frozen allograft sterilized without gamma radiation) and retrospectively evaluated with a mean of 12, 5 years in the femoral group and 11.2 years in the tibial group. Results: No patient had an extension deficit. The mean flexion of the knee was 96.4º in the femoral group and 94º in the tibial group. The mean of the MSTS (Musculoskeletal Tumor Society) scale was 23.2 in the femoral group and 24.7 in the tibial group. The allograft integration did not present mechanical complications in the groups. The survival of the allograft-prosthetic composite at 10 years was 94.1% in the femoral group and 83.3% in the tibial group. Conclusions: Treatment for malignant tumors of the distal femur with allograft-prosthetic composite has shown effectiveness at least similar to the proximal tibia localization.