Perioperative Complications and Mortality Following 24,506 Below-Knee Amputations in the United States: A Large, Retrospective Cohort Study

INTRODUCTION: Below-knee amputation (BKA) is a critical lower-extremity intervention but remains associated with substantial morbidity and mortality. Prior studies are often limited by small cohorts, single-center designs, or narrow outcome definitions, leaving contemporary national estimates of postoperative risk incompletely characterized. METHODS: The TriNetX United States Collaborative Network was used to perform a retrospective cohort study. Outcomes included orthopedic, wound/stump, medical, and psychiatric complications, as well as mortality, assessed at 30 d, 90 d, 6 mo, 1 y, and 2 y. Descriptive statistics summarized demographics and complication rates. RESULTS: A total of 24,506 patients underwent BKA (mean age 60 ± 14.1 y; 68% male). Conversion to above-knee amputation occurred in 5.4% at 30 d and 11.3% at 2 y; revision BKA occurred in 6.1% and 11.6%, respectively. Infection was the most common wound complication, rising from 9.0% at 30 d to 22.6% at 2 y. Phantom limb pain occurred in 11% at 30 d and 20% at 2 y. Sepsis was the most frequent medical complication, affecting 23% by 2 y. New psychiatric diagnoses increased over time, with depression reaching 11.2%, anxiety 8.7%, and PTSD 1.0% at 2 y. Mortality was 3.3% at 30 d, 12.4% at 1 y, and 17.1% at 2 y. CONCLUSIONS: Patients undergoing BKA experience a substantial burden of postoperative complications and significant short-term and long-term mortality. These findings emphasize the risks associated with BKA and highlight the need for comprehensive perioperative optimization, multidisciplinary care, and long term follow up to mitigate adverse outcomes in this population.