Fig. 2.

Effect of femoral perineural ropivacaine infusion on the time to reach three important discharge criteria (adequate analgesia, independence from intravenous opioids, and the ability to ambulate at least 30 m) after tricompartment total knee arthroplasty. Data presented are Kaplan-Meier estimates of the cumulative percentages of patients meeting all three discharge criteria at each time point and subsequent time points. Data are for patients randomly assigned to the ropivacaine group (perineural ropivacaine from surgery through postoperative day 4) or the placebo group (perineural ropivacaine from surgery through 06:00 postoperative day 1 followed by perineural normal saline through postoperative day 4).