Although elevation of the upper limb is considered valuable for the prevention and of the reduction of swelling following major surgery or severe injuries to the hand, it is not clear how much elevation, if any, is required following minor surgery such as carpal tunnel decompression. We investigated this by randomizing patients undergoing carpal tunnel decompression into two groups - one having high elevation at home and one being treated with a simple sling. Volumetric analysis of the swelling of the hand 5 days postoperatively showed no significant difference between the two groups. In the trial group, the mean increase in volume of the operated hand was 11 ml (95% CI +4 to +17) or 2.7%. In the control group, the mean swelling was 13 ml (95% CI +4 to +21) or 3.6%. The findings of this study do not support the use of routine high arm elevation following day-case surgery of the hand.