Risk Factors and Incidence of 30-Day Readmission Following Outpatient Total Knee Arthroplasty.

BACKGROUND

Reflecting advancements in surgical techniques and postoperative care, total knee arthroplasty (TKA) is being performed increasingly as an outpatient procedure. This study aimed to report the frequency and timing of unplanned readmission after outpatient TKA with updated data, identify risk factors for readmission after outpatient TKA, and identify common causes for readmission after outpatient TKA with a much larger cohort compared to previous studies.

METHODS

This study retrospectively analyzed data from 31,347 patients who underwent outpatient TKAs between 2012 and 2021. Adverse events and unplanned readmissions were identified. Timing and reason for readmission were recorded. Statistical analysis involved multivariate logistic regression to identify patient risk factors for readmission.

RESULTS

Following surgery, 1.86% of cases reported an unplanned readmission within 30 days. Multivariate analysis demonstrated that age (odds ratio (OR): 1.042; P < 0.001), body mass index (OR: 1.023; P = 0.002), operative time (OR: 1.003; P = 0.017), congestive heart failure (OR: 3.079; P < 0.001), chronic obstructive pulmonary disease (OR: 2.577; P < 0.001), bleeding disorders (OR: 1.706; P = 0.025), hypertension (1.436; P < 0.001), and partially dependent functional status (OR: 2.486; P = 0.036) significantly increased the risk of 30-day readmission. Reasons unrelated to the surgical site contributed the most to readmission at 68.3%, while reasons related to the surgical site made up 27.3%, followed by knee-related complaints (4.4%). The most common days on which readmissions occurred were postoperative days two, four, and one.

CONCLUSIONS

Our analysis revealed a low readmission risk (1.86%) after outpatient TKA. Readmission rates were found to decrease over the observed time, despite a dramatic increase in outpatient cases. The most common reason for 30-day readmission was an organ or space surgical site infection. Identified risk factors for readmission highlight areas for targeted mitigation to enhance patient outcomes and healthcare efficiency.