Purpose <p>Intertrochanteric femoral fractures are among the most frequent injuries in the elderly, and the use of cephalomedullary nails has increased in recent years. In this context, the concept of positive, neutral, or negative anteromedial cortical support proposed by Chang has been associated with mechanical stability and clinical outcomes in unstable fractures. The aim of this retrospective study was to analyze the impact of different cortical support patterns in patients over 65 years with intertrochanteric fractures treated with short cephalomedullary nails, evaluating their influence on mechanical stability and fracture union.</p> Methods <p>Patients older than 65 years with AO/OTA 31A2.2 and 31A2.3 intertrochanteric fractures treated with a short cephalomedullary nail and a minimum follow-up of six months were included. Data were collected regarding anteroposterior and lateral cortical support, tip-apex distance (TAD), calcar-referenced TAD (cal-TAD), union, complications, and mortality.</p> Results <p>A total of 158 patients were analyzed. The overall union rate was 92.4% (<i>n</i> = 146). Negative cortical support was significantly associated with nonunion in the anteroposterior view (<i>p</i> &lt; 0.000003; RR, 1.4; 95% CI, 1.1–1.8) and in the lateral view (<i>p</i> &lt; 0.000009; RR, 1.2; 95% CI, 1.0–1.4). The overall complication rate was 13.9%, and mortality was 10.1%.</p> Conclusions <p>Pertrochanteric fractures treated with short cephalomedullary nails in patients older than 65 years showed high union rates. However, negative reduction in either anteroposterior or lateral projections was significantly associated with an increased risk of nonunion.</p> Level of evidence <p>IV.</p>