One-Day vs Two-Day Epidural Analgesia for Total Knee Arthroplasty (TKA): A Retrospective Cohort Study

INTRODUCTION Over 500,000 total knee arthroplasties (TKAs) are performed annually in the US, yet postoperative pain management varies widely. In patients managed with epidural analgesia, the epidural catheter is generally removed on the second postoperative day. We compared in-hospital outcomes associated with removing the epidural catheter on postoperative day 1 (POD1-group) vs on postoperative day 2 (POD2-group) among patients undergoing TKA. METHODS We identified 89 patients who had TKA performed by a single surgeon from January through July 2007, and who were managed with epidural analgesia. This study took advantage of a change of policy from removing the epidural on the second postoperative day prior to March 2007 (n = 34) to removing the epidural on the first postoperative day thereafter (n = 55). Data were obtained by medical record review and analyzed with bivariate and multivariate techniques. Outcomes included knee range of motion (ROM), pain (0-10 scale), distance walked, narcotic usage, and length of stay. RESULTS The mean patient age was 68 +/- 10 years. We did not identify clinically important differences in preoperative characteristics across groups. Patients in the POD1- group had a shorter length of stay (median of 3 vs 4 days in the POD2-group, p<0.001). The POD1-group also walked a greater distance on the second postoperative day (mean of 38 feet vs 9 feet in the POD2-group, p < 0.002). We did not observe a difference between the two groups with respect to change in passive ROM, pain on the second postoperative day, or narcotic usage. The POD1-group had more restricted continuous passive motion settings on the second postoperative day than the POD2-group (50 degrees vs 65 degrees , p = 0.031), and the POD1-group had somewhat worse passive range of motion at discharge (e.g. passive flexion 82o vs 76o in the POD2- group, p = 0.078). CONCLUSION The balance between a shorter hospital stay and earlier walking achievement with the POD1-strategy-- vs better ROM at the time of discharge with the POD2-strategy-- should be considered when planning TKA pain management. These results should be confirmed with longer term studies and randomized designs. EVIDENCE LEVEL III: Retrospective comparative study.