Outcomes of distal femoral replacement versus internal fixation for metastatic bone diseases of the distal femur.

Background: In clinical practice, internal fixation (IF) is a commonly utilized technique for metastatic bone disease (MBD) to the distal femur. Additionally, distal femoral reconstruction (DFR) has shown to be an effective surgical technique for primary tumors and MBD in the distal femur. The existing body of research comparing these methods has not focused on MBD or pathological fractures and thus does not guide surgical approach in the case of distal femoral MBD. Methods: A multi-institutional retrospective review of musculoskeletal oncology patients treated surgically with IF (n = 29) or DFR (n = 34) for distal femoral MBD between 2005 and 2023. Overall survival, revision risk, and functional status were assessed. Results: 5-year patient overall survival was 47.9 % (CI, 29.5-77.6 %) and 46.6 % (CI, 31.5-68.8 %), for DFR and IF, respectively (p = 0.91). After competing risk analysis, the 5-year risk of implant revision for DFR was 18 % (95 % CI: 5.1-37 %) and 11 % for IF (95 % CI: 2.4-28 %) (p = 0.3). DFR had longer operative times (p = 0.002), higher blood loss (p < 0.001), and greater postoperative (p = 0.006) complications than IF. In addition, patients undergoing DFR had more distal lesions than patients who received IF (p = 0.003). Conclusion: Despite similar overall survival and revision rates, IF may be preferable for patients due to its shorter operative time and lower rates of complication than DFR. However, specific anatomic location in the distal femur must be considered prior to deciding which procedure is optimal.