Purpose <p>Interprosthetic femur fractures (IPFFs) represent an increasingly important challenge in orthopedic trauma surgery, reflecting the rising prevalence of hip and knee arthroplasties in an aging population. This study aimed to describe patient characteristics, evaluate surgical fixation strategies, and identify prognostic factors for union, complications, and mortality.</p> Methods <p>A retrospective cohort study was conducted at a District General Hospital between August 2020 and August 2023. Fifteen consecutive patients with radiologically confirmed IPFFs treated surgically and followed for at least 12 months were included. Data collected included demographics, frailty, perioperative variables, fixation methods, radiological healing, complications, and mortality. Kaplan–Meier survival and Cox regression were applied to assess outcomes and predictors.</p> Results <p>The mean patient age was 84.6 years (80% female) with a mean frailty score of 4.27. Surgical strategies included lateral plate fixation (40%), linked nail–plate constructs (33.3%), dual plating (13.3%), and revision procedures (13.3%). Median time to surgery was 2 days, with 73.3% operated within 72&#xa0;h. Radiological union was achieved in 60% of patients at a mean of 6.1 months, while reoperation was required in 13.3% of cases. Mortality was 0% at 30 days, 6.7% at 90 days, and 26.7% at one year. Frailty score ≥ 5 was associated with delayed union (HR 0.65, 95% CI 0.40–0.95, <i>p</i> = 0.03).</p> Conclusion <p>IPFFs are associated with high morbidity, delayed union, and significant one-year mortality. Early surgery within 72&#xa0;h was achievable in this cohort, and no 30-day mortality was observed, though causality cannot be established given the study design. Frailty emerged as a key prognostic indicator, underscoring the importance of comprehensive risk assessment and individualized treatment planning. Larger studies are needed to establish optimal fixation strategies based on fracture classification and patient factors.</p>