General anesthesia is associated with increased postoperative morbidity and mortality in frail patients undergoing hip fracture fixation.

INTRODUCTION: Anesthetic management of hip fracture fixation has two primary modalities: general anesthesia (GA) and spinal anesthesia (SA). Choice of anesthesia often depends on institutional protocols and the individual anesthesiologist, due to a lack of consensus guidelines. Most studies have conflicting evidence and focus primarily on elderly age as a risk factor, without accounting for frailty. This study investigates whether frailty influences the relationship between anesthetic modality and postoperative outcomes.

METHODS: This retrospective study queried the ACS-NSQIP from 2015 to 2020 for patients who underwent hip fracture fixation with open reduction internal fixation with plate and screws or intramedullary implant insertion. Patients were separated based on whether they received GA or SA. Frailty was evaluated using the 5-Item Modified Frailty Index (mFI-5). Patients classified as frail or severely frail were included. Multivariable regression adjusting for age, sex, ASA classification, smoking, and the comorbidities significant on univariate regression was performed. The outcomes examined were mortality, unplanned readmission, and overall complications within 30 days postoperatively.

RESULTS: This study included 24,401 patients under GA and 6193 patients under SA. On multivariable regression analysis, GA was independently associated with increased odds of mortality, unplanned readmission, and all complications among frail patients. Severely frail patients under GA had increased odds of unplanned readmission and all complications. When looking at both frail and severely frail patients together, GA remained a significant predictor of mortality, unplanned readmission, and all complications.

DISCUSSION: After controlling for ASA classification, our study found that frail and severely frail patients undergoing GA for hip fracture fixation had significantly increased odds of mortality, unplanned readmission, and all complications. Our findings suggest that SA may be safer compared to GA in frail patients undergoing hip fracture fixation. Frail patients that undergo GA may benefit from increased postoperative monitoring to help mitigate complications.