Long-Term Results of Kyocera Modular Limb Salvage System after Resection of Tumors in the Distal Part of the Femur: Report from Japanese Musculoskeletal Oncology Group Study

SIMPLE SUMMARY: We aimed to elucidate the long-term outcomes of a distal femur reconstruction system in 125 patients with bone and soft tissue tumors. Implant survival rates at 10 and 15 years were 58.5% and 39.4%. Stem breakage should be considered in patients with cementless and/or smaller femoral stem sizes. Aseptic loosening should be considered in patients with a cement system after 10 years. ABSTRACT: Background: The distal femur is a common site of bone tumors. After surgical resection, prosthetic replacement is a major reconstruction method. We aimed to elucidate the long-term outcomes of the Kyocera Modular Limb Salvage (KMLS) systems after resection of tumors in the distal part of the femur. Methods: Between 1998 and 2014, 125 patients were treated at 14 institutions. There were 59 males and 66 females, with a mean age of 35 years. The mean follow-up period was 132 months. Results: There had been 65 additional surgeries, including 56 revisions and 9 amputations: 15 for aseptic loosening, 14 for stem breakage, 13 for deep infection, 13 for rotator-hinge bushing failure, 5 for local recurrence, and 5 for others. Implant survival rates at 10 and 15 years were 58.5% and 39.4%. The cumulative incidence of 15-year revision for femoral stem breakage was 31.7% in patients with cementless fixation. The 15-year cumulative incidence of revision for aseptic loosening was 19.8% in patients with cement fixation. Conclusions: KMLS systems represent a reliable system with long-term results. Stem breakage should be considered in patients with cementless and/or smaller femoral stem sizes. Aseptic loosening should be considered in patients with cement systems after 10 years.