Minimally Invasive Treatment of Three-Part Proximal Humerus Fractures: A Two-Center Comparative Study of Plate Fixation and Intramedullary Nailing

<b>Background/Objectives:</b> Proximal humerus fractures account for approximately 5% of all skeletal injuries, and their optimal surgical management remains debated. The optimal fixation method for three-part proximal humerus fractures remains a matter of debate. This study aimed to compare the clinical and radiological outcomes of two minimally invasive osteosynthesis techniques-plate fixation and intramedullary nailing-for the treatment of three-part proximal humerus fractures. <b>Methods:</b> Sixty-six patients aged 60-80 years were retrospectively analyzed across two centers adopting different institutional preferences. Thirty-three patients were treated with minimally invasive plate fixation and thirty-three with intramedullary nailing. The mean age was 67.8 ± 4.2 years, and the mean follow-up duration was 27.2 months. Functional and clinical outcomes were evaluated using the Barthel Index, DASH, Simple Shoulder Test (SST), and Visual Analog Scale (VAS). Operative time, hospitalization length, healing time, and postoperative complications were recorded and statistically analyzed. <b>Results:</b> Intramedullary nailing was associated with shorter operative and hospitalization times and fewer complications. Early SST and VAS improvements favored the nailing group, while long-term outcomes were comparable. <b>Conclusions:</b> Intramedullary nailing represents a reliable and less invasive alternative to plate fixation in the treatment of three-part proximal humerus fractures. It offers shorter operative and hospitalization times, fewer postoperative complications, and faster functional recovery while achieving comparable long-term outcomes. Surgeon experience and familiarity with the chosen technique remain key determinants of success.