Long-term followup of uncemented tumor endoprostheses for the lower extremity

Between 1982 and 1989, 100 primary lower limb reconstructions were done using the Kotz Modular Femur Tibia Reconstruction System after resection of a malignant tumor. In 32 patients a proximal femur prosthesis was implanted, in 40 patients a distal femur prosthesis was implanted, in 19 patients a proximal tibia component was implanted, in four patients a total femur prosthesis was implanted, and in five patients a total knee prosthesis was implanted. The Kaplan-Meier estimate of the overall survival rate of the prostheses was 85% after 3 years, 79% after 5 years, and 71% after 10 years. The most common reason for implant failure was aseptic loosening in 27% of patients (11 patients; range, 10-121 months) after the initial operation. The other reasons for revision surgery were implant fracture (n 5 4) and infection (n 5 4). Early repair of prostheses-related minor complications, such as worn polyethylene bushings, resulted in a statistically significant reduction of implant failure. After a median followup of 127.5 months after the initial surgery, 51 patients had died and eight patients were lost to followup. Forty-one patients were evaluated clinically and radiologically using the Musculoskeletal Tumor Society score and the radiologic implant evaluation system of the International Symposium on Limb Salvage; these 41 patients had a mean of 80% (range, 40%-100%) of the normal functional capability.