Abstract
BACKGROUND: Pathological subtrochanteric fractures pose challenges due to the high biomechanical demands of this region and the systemic complexity of metastatic disease. At present, the optimal fixation method remains controversial, particularly between intramedullary nailing (IMN) and dynamic hip screw (DHS) fixation. This study compared the mechanical, oncological, and functional outcomes of these two treatment strategies. METHODS: This retrospective study reviewed patients treated for metastatic subtrochanteric fractures at a single tertiary referral center between 2002 and 2018. Demographic, surgical, and tumor-related characteristics were assessed. Primary outcomes included implant breakage, mechanical failure, local tumor progression, distal canal seeding, and revision surgery. Functional outcomes were evaluated using the Musculoskeletal Tumor Society (MSTS) scoring system, and survival was analyzed using the Kaplan-Meier method. RESULTS: Ninety patients met the inclusion criteria, including 48 treated with IMN and 42 treated with DHS fixation. DHS fixation was associated with a higher rate of implant breakage (16.7% vs 2.1%; p = 0.023), but lower rates of local tumor progression (4.8% vs 22.9%; p = 0.017) and distal canal seeding (0% vs 18.8%; p = 0.003). Revision surgery (21.4% vs 14.6%; p = 0.422), perioperative complications, MSTS functional scores, and median survival (20.3 vs 20.1 months; p = 0.938) were comparable between groups. CONCLUSION: Although IMN remains essential for many pathological subtrochanteric fractures, its association with higher rates of local progression and distal canal seeding underscores the importance of careful patient selection. In appropriately selected patients, particularly those with extensive bone loss, narrow medullary canals, or elevated hemodynamic or thromboembolic risk, DHS fixation may provide a less invasive and oncologically favorable alternative with comparable functional and survival outcomes.