5-Factor Modified Frailty Index predicts 30-day complications after amputation for open lower-extremity fracture: an American College of Surgeons Trauma Quality Improvement Program database study.

PURPOSE: Open lower-extremity fractures are high-energy injuries, with severe cases necessitating amputation. While frailty predicts adverse surgical outcomes, its role in postoperative risk among patients undergoing amputation for open lower-extremity fractures has not been defined. This study aimed to determine whether frailty, measured by the 5-Item Modified Frailty Index (mFI-5), predicts 30-day postoperative complications following surgical amputation for open lower-extremity fractures. METHODS: This retrospective cohort study utilized the American College of Surgeons Trauma Quality Improvement Program database (2017-2021). Adults (≥ 18 years) with open lower-extremity fractures undergoing surgical amputation were identified using ICD-10 codes. Frailty was assessed using the mFI-5 (score range 0-5). The primary outcome was surgical site infection; secondary outcomes included cardiopulmonary complications, thromboembolic events, pressure ulcer development, and ICU admission. Multivariable logistic regression adjusted for age, sex, Injury Severity Score (ISS), insurance status, Gustilo-Anderson fracture type, smoking status, and vascular injury determined the association between mFI-5 and 30-day complications. RESULTS: Among 1122 patients (mean age 46.7 years, 78.5% male), the mean mFI-5 score was 0.46 (SD 0.81) and mean ISS was 18.55 (SD 10.95). After adjustment, each one-point increase in mFI-5 was independently associated with significantly increased odds of surgical site infection (OR 1.36), cerebrovascular accident (OR 2.93), reintubation (OR 2.17), ICU admission (OR 1.56), and pressure ulcer development (OR 1.68). CONCLUSION: The mFI-5 independently predicts major 30-day postoperative complications following amputation for open lower-extremity fractures, including cerebrovascular, respiratory, and wound-related complications. Routine mFI-5 screening may enhance preoperative risk stratification, inform perioperative optimization, and facilitate shared decision-making in this vulnerable population.