Factors associated with prolonged length of hospital stay in primary total knee arthroplasty following enhanced recovery after surgery protocol：a single‑center retrospective study

Background Decreasing the length of stay (LOS) is an ideal way to appropriately allocate medical and health resources. This study aims to analyze the risk factors of prolonged LOS after total knee arthroplasty (TKA) following enhanced recovery after surgery (ERAS) protocol. Methods 220 patients who underwent primary TKA in strict accordance with ERAS protocol from January 2018 to December 2021 were included in the retrospective study. Prolonged LOS was defined as more than 5 days. The factors with a P value less than 0.1 in the univariate analysis were further analyzed in a multivariate model. A binary Logistic regression was performed to screen the independent risk factors for a prolonged LOS. Results Binary Logistic regression multivariate analysis showed patients' age (OR = 3.320, 95%CI 1.209–9.115, P = 0.020), complications of ischemic heart disease (OR = 4.917, 95%CI 1.046–23.114, P = 0.044), operation time (OR = 1.966, 95%CI 1.006–3.840, P = 0.048) and surgical day of the week (OR = 0.268, 95%CI 0.092–0.786, P = 0.016) were independent risk factors for prolonged LOS. Further stratified analysis showed that patients older than 70 years had 3.32 times the risk of prolonged LOS compared with patients younger than 60 years. Patients with more than 90 minutes of surgery had 1.966 times the risk of prolonged LOS compared with patients with less than 90 minutes of surgery. Having surgery on Monday is significantly associated with the highest odds of prolonged LOS. Conclusions Patients older than 70 years, operation time of more than 90 minutes, with ischemic heart disease, and having surgery on Monday are independent risk factors for prolonged LOS after TKA following ERAS protocol. Early identification and optimization of these factors can help shorten LOS and further maximize the use of medical resources.