Effects of Anesthetic Technique on Outcomes After Hip Fracture Surgery in Geriatric Patients: A Retrospective Observational Study

Abstract

Background: Hip fractures in older adults almost always require surgery under general or neuraxial anesthesia. While the influence of anesthetic technique on mortality has been studied extensively, its relationship with resource-related outcomes such as hospital length of stay is less well characterized, particularly in high-volume trauma settings. Objective: To determine whether anesthetic technique is associated with hospital length of stay in geriatric patients undergoing hip fracture surgery (primary objective). Secondary objectives were to compare ICU admission and length of stay, and postoperative adverse events across techniques, and to identify patient comorbidities associated with a prolonged hospital stay. Materials and methods: This single-center retrospective observational study included 265 consecutive patients aged ≥65 years undergoing acute hip fracture surgery between April 2022 and March 2023. Patients were grouped by anesthetic technique: subarachnoid block (SAB), combined spinal-epidural anesthesia (CSE), or general anesthesia (GA). Length of stay was compared across techniques using the Kruskal-Wallis test with Dunn’s post hoc comparisons; ICU admission and adverse events using Fisher’s exact test; and comorbidity-length-of-stay associations using the Mann-Whitney U test. A multivariable negative-binomial model estimated adjusted incidence-rate ratios (IRRs). Results: The median hospital length of stay was five days (interquartile range 3-7) and differed significantly by technique (SAB four days, GA six days, CSE nine days; p < 0.001), a gradient that persisted after adjustment (adjusted IRR versus SAB: CSE 2.84 (95% CI 2.51-3.22), GA 1.72 (1.44-2.05)). ICU admission (CSE 13.2%, GA 6.1%, SAB 2.6%; p = 0.006) and any postoperative adverse event (CSE 17.1%, GA 9.1%, SAB 3.8%; p = 0.002) were likewise highest after CSE. In-hospital mortality (1.5%) and 30-day readmission (1.9%) did not differ by technique. A longer stay was associated with coronary artery disease, renal disease, and a prior stroke. Conclusions: Hospital length of stay, ICU admission, and postoperative adverse events were greatest among patients receiving CSE anesthesia and least among those receiving SAB, whereas in-hospital mortality did not differ by technique. Given the observational design and the broadly similar baseline characteristics across groups, these differences most likely reflect the indications for each technique and the care pathways associated with it rather than an effect of anesthesia itself. Anesthetic techniques for geriatric hip fracture surgery can therefore be individualized to patient and operative factors, and prospective studies are needed to confirm these associations and clarify their mechanisms.