Abstract
Total hip arthroplasty (THA) is performed under general anesthesia (GA) or spinal anesthesia (SA). The first objective of this study was to determine which patient factors are associated with receiving SA versus GA. The second objective was to discern the effect of anesthesia type on short-term postoperative complications and readmission. The third objective was to elucidate factors that impact the effect of anesthesia type on outcome following arthroplasty.
This retrospective cohort study included 108,905 patients (median age, 66 years; IQR 60-73 years; 56.0% females) who underwent primary THA for treatment of primary osteoarthritis in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database during the period of 2013-2018. Multivariable logistic regression analysis was performed to evaluate variables associated with anesthesia type and outcomes following arthroplasty.
Anesthesia type administered during THA was significantly associated with race. Specifically, Black and Hispanic patients were less likely to receive SA compared to White patients (White: OR 1.00; Black: OR 0.73; 95% confidence interval [CI] 0.71-0.75; Hispanic: OR 0.81; CI, 0.75-0.88), while Asian patients were more likely to receive SA (OR 1.44, CI 1.31-1.59). Spinal anesthesia was associated with increased age (OR 1.01; CI 1.00-1.01). Patients with less frailty and lower comorbidity were more likely to receive SA based on the modified frailty index ([mFI-5]=0: OR 1.00; mFI-5=1: OR 0.90, CI 0.88-0.93; mFI-5=2 or greater: OR 0.86, CI 0.83-0.90) and American Society of Anesthesiologists (ASA) class (ASA=1: OR 1.00; ASA=2: OR 0.85, CI 0.79-0.91; ASA=3: OR 0.64, CI 0.59-0.69; ASA=4-5: OR 0.47; CI 0.41-0.53). With increased BMI, patients were less likely to be treated with SA (OR 0.99; CI 0.98-0.99).
Patients treated with SA had less post-operative complications than GA (OR 0.74; CI 0.67-0.81) and a lower risk of readmission than GA (OR 0.88; CI 0.82-0.95) following THA. Race, age, BMI, and ASA class were found to affect the impact of anesthesia type on post-operative complications. Stratified analysis demonstrated that the reduced risk of complications following arthroplasty noted in patients treated with SA compared to GA was more pronounced in Black, Asian, and Hispanic patients compared to White patients. Furthermore, the positive effect of SA compared to GA was stronger in patients who had reduced age, elevated BMI, and lower ASA class.
Among patients undergoing THA for management of primary osteoarthritis, factors including race, BMI, and frailty appear to have impacted the type of anesthesia received. Patients treated with SA had a significantly lower risk of readmission to hospital and adverse events within 30 days of surgery compared to those treated with GA. Furthermore, the positive effect on outcome afforded by SA was different between patients depending on race, age, BMI, and ASA class. These findings may help to guide selection of anesthesia type in subpopulations of patients undergoing primary THA.
