Fig. 3. Relationship between the mean (± SD) total patient-controlled analgesia (PCA) morphine use (mg) during the 72-h study period (black bars ) and the average (median) verbal pain score (diamonds ) on an 11-point verbal rating scale (VAS), where 0 = no pain to 10 = worst pain imaginable. The correlation coefficients were −0.168, 0.638, and 0.392 in the control, bupivacaine-0.25% and bupivacaine-0.5% groups, respectively.