Long-Term Outcomes and Risk Factors for Implant Failure After Distal Femoral Megaprosthesis in Orthopaedic Oncology: A Single-Center Retrospective Study.

Background: Distal femoral replacement (DFR) is a standard reconstruction technique following malignant bone tumor resection, yet long-term outcomes and implant-related complications remain insufficiently reviewed. Methods: We retrospectively analyzed 88 patients who underwent DFR for malignant or aggressive benign tumors from 1990 to 2023. The cumulative incidences of implant revision, removal, or amputation were estimated using competing risk analysis with death as a competing event. Risk factors for major reoperation were identified through univariate and multivariate analyses. Results: Over a median follow-up of 8.0 years, 71 reoperations were performed in 41 patients (30 major and 41 minor). The cumulative incidence of implant removal or revision was 19.8% at 5 years, 36.8% at 10 years, and 52.2% at 20 years. Type 4 complications (infection) were the most common cause of failure, including late-onset infections occurring more than 10 years postoperatively. In multivariate analysis, the presence of a residual epiphyseal plate (hazard ratio: 4.17, Conclusions: DFR provides durable long-term outcomes, though the risk of revision persists beyond 10 years, primarily due to infection. Residual epiphyseal plate presence is a significant risk factor for implant failure. Complex surgical procedures were not independently associated with implant failure in the adjusted analysis.