Fig. 5. Time course of plasma interleukin (IL)-6 and soluble receptor 1 of tumor necrosis factor (sTNF-R1) levels. IL-6 (  A ) and sTNF-R1 (  B ) plasma levels before surgery (D0) and at 4 h (H4) and 1 (D1), 4 (D4), and 7 days (D7) 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; pg/ml = picograms of cytokine per milliliter of plasma. We did not observe significant differences between the groups.