Figure 1. Visual analog scale scores expressed in millimeters in groups of intra-articular saline, neostigmine (125, 250, and 500 micro gram), morphine (2 mg), or subcutaneous neostigmine (500 micro gram) given over 48 h. Data are presented as means +/- SD of 10 patients per group. The asterisk indicates a significant difference in VAS reduction 1 h after operation of 500 micro gram intra-articular neostigmine compared with all other groups (P < 0.05), excluding subcutaneous neostigmine (P > 0.05).