Fig. 5. Effects of posterior lumbar plexus perineural ropivacaine infusion on intravenous morphine consumption after hip arthroplasty. Kaplan-Meier estimates include the cumulative percentages of morphine-free patients at each time point and subsequent time points. Other data are expressed as median (  horizontal bar ) with 25th–75th (  box ) and 10th–90th (  whiskers ) percentiles 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). Because each comparison dilutes all other  P values, we restricted our analysis to 11 comparisons among secondary endpoints.  P values are presented where statistical comparisons were applied. PACU = postanesthesia care unit.