Endoprosthetic reconstruction versus osteosynthesis for metastatic disease of the proximal femur: a population-based cohort study.

PURPOSE: To compare implant failure, revision surgery, and overall patient survival following endoprosthetic reconstruction versus osteosynthesis in patients undergoing surgery for metastatic bone disease of the proximal femur (MBDf).

METHODS: This population-based cohort study included all patients treated surgically for MBDf at six institutions in the Greater Copenhagen area, Denmark, between 2013 and 2019. Implant failure and revision surgery were analysed using competing risk models, with death treated as a competing event. Overall survival was estimated using Kaplan-Meier analysis.

RESULTS: A total of 281 patients were included, of whom 81 underwent osteosynthesis and 200 underwent endoprosthetic reconstruction. Implant failure was more frequent following osteosynthesis than endoprosthetic reconstruction, with cumulative incidences of 5% (CI 0.2 to 10), versus 0.5% (CI 0 to 1.5) at three months, 7% (CI 2 to 13) versus 0.5% (CI 0 to 1.5) at six months, and 7% (CI 2 to 13) versus 1% (CI 0 to 2.4) at twelve months. Revision surgery rates were comparable between the groups with cumulative incidences of 5% (95% CI 0.2-10) versus 3% (95% CI 0.6-5) at three months, 7% (95% CI 2-13) versus 4% (95% CI 1-6) at six months, and 9% (95% CI 3-15) versus 4% (95% CI 2-7) at twelve months. Overall survival was lower in patients treated with osteosynthesis compared with endoprosthetic reconstruction (p = 0.01).

CONCLUSION: Endoprosthetic reconstruction is superior in terms of risk of implant failure compared to osteosynthesis in patients treated for MBDf, but no difference was found in overall revision risk.