Figure 1. Perioperative serum glycine (open square) and serum sodium (closed circle) concentrations. Data are means +/- SD. (section)(section)P < 0.01 serum glycine compared with 0. mS normal serum glycine concentration: 229 +/- 44 micro mol/L. **P < 0.01 serum sodium compared with 0. 0 = before arthroscopy; PO = immediately after arthroscopy; 3, 6, 9, 12, 18, 24 = 3, 6, 9, 12, 18, 24 h, respectively, after arthroscopy.