Fig. 1. Time course of visual analog pain score. Visual analog pain scores at rest (  A ) and when moving (  B ) at 1 (D1), 4 (D4), and 7 days (D7) and 1 (M1) and 3 months (M3) after surgery. Values are expressed as mean ± SEM. Block group = patients treated by combined sciatic (single-shot) and femoral (continuous for 48 h after surgery) nerve blocks; PCA group = patients treated by morphine patient-controlled analgesia. Pain was reduced in patients from the block group between D1 and D7 at rest (analysis of variance, group effect,  P = 0.005).  Post hoc analysis showed significant differences at D4 (  t test,  P = 0.01) and D7 (  t test,  P = 0.002) between the two patient groups. Pain when moving was reduced in the block group between D1 and D7 (analysis of variance, group effect,  P = 0.0005;  B ).  Post hoc analysis showed significant differences at D1 (  t test,  P = 0.003), D4 (  t test,  P = 0.002), and D7 (  t test,  P = 0.001) between patient groups. **  t test,  P < 0.01. ***  t test,  P < 0.001.