Reasons and Risk Factors for Emergency Department Visits After Primary Total Knee Arthroplasty: An Analysis of 1.3 Million Patients

Background: Well-powered studies investigating the relationship of emergency department (ED) visits and total knee arthroplasty (TKA) are limited. Therefore, the specific aims of this study were to: 1) compare patient demographics of patients who did and did not have an ED visit; and for the visits, identified: 2) leading reasons; and 3) risk factors for ED visits (prearthroplasty/postarthroplasty).

Methods: Patients undergoing primary TKA who had an ED visit within 90 days after their index procedure were identified from a nationwide database. The query yielded 1,364,655 patients who did (n = 5689) and did not have (n = 1,358,966) an ED visit. Baseline demographics such as age, sex, and comorbidity prevalence between the two cohorts; reasons for ED visits; and prearthroplasty and postarthroplasty risk factors were analyzed. Odds ratios (ORs) of ED visits were assessed using multivariate binomial logistic regression analyses. A P-value less than 0.001 was considered statistically significant.

Results: Patients who did and did not have ED visits differed with respect to age (P < .0001) and mean Elixhauser Comorbidity Index scores (9 vs 6, P < .0001). Musculoskeletal etiologies were the most common reason for ED visits. Hypertension was the greatest contributor to ED visits prearthroplasty and postarthroplasty. Comorbid conditions associated with ED visits postarthroplasty included peripheral vascular disease (OR: 1.61, P < .0001), coagulopathy (OR: 1.58, P < .0001), and rheumatoid arthritis (OR: 1.56, P < .0001).

Conclusion: By identifying demographic patterns of patients, reasons, and risk factors, the information found from this study can help identify targets for quality improvement to potentially reduce the incidence of ED visits after primary TKA.

Keywords: costs; database; emergency department; risk factors; total knee arthroplasty.