Fig. 4. Effects of posterior lumbar plexus perineural ropivacaine infusion on postoperative pain after hip arthroplasty. Pain severity indicated using a numeric rating scale of 0–10, with 0 equal to no pain and 10 being the worst imaginable pain. 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. For this reason, no statistical comparisons were applied to the data of this figure. PACU = postanesthesia care unit.