Predicting Surgical Factors for Unplanned Overnight Admission in Ambulatory Arthroscopic Surgery of the Knee: A Prospective Cohort in 184 patients

Abstract

Background: Unplanned overnight admission (UOA) is an important indicator for quality of care with ambulatory knee arthroscopic surgery (AKAS). However, few studies have explored the factors related to the UOA and how to predict UOA after AKAS. This study aimed to evaluate the effectiveness of a standardized perioperative protocol for the AKAS with UOA and identify whether a correlation exists between the perioperative surgical factors and UOA in the patients undergoing AKAS. Methods: A prospective cohort study was conducted, between October 2017 and March 2021, in 184 patients. All patients operated on standard AKAS protocol. The UOA was defined as overnight hospitalization of a patient undergoing AKAS. Demographic and perioperative data were recorded, and the procedure was categorized based on the surgical invasiveness based on less invasive (n = 65) and more complex surgery (n = 119). The clinical risk factors for UOA were identified and analyzed with multivariate logistic regression analysis. Results: The incidence of UOA in the more complex group (17 cases, 14.3%) was significantly higher than in the less invasive group (3 cases, 4.6%) (p = 0.049), with the incidence of readmission as 0%. The perioperative factors significantly associated with UOA were age, more complex surgery, and tourniquet time (p < 0.10 all). However, the multivariate regression analysis revealed that tourniquet time was the only significant predictor for UOA (odds ratio = 1.045, 95% confidence interval = 1.022 to 1.067, p = 0.0001). The optimal cut-off points of tourniquet time for predicting UOA with the highest Youden index in the less invasive and more complex groups were 56 minutes and 107 minutes, respectively. Conclusion: The UOA after AKAS is more common in more complex surgery compared to less invasive surgery. Many factors—such as patient factors, surgical invasiveness, and tourniquet time—were also significantly associated with the unplanned admission. However, the results from this study showed that, under strict perioperative management protocol, tourniquet time is the only independent predictor for UOA.