The adjuvant dexamethasone has increasingly become a subject of interest regarding a protracted effect, which has been shown in several studies. However, the precise mechanism of action remains speculative, and the results are contradictory regarding the discussion whether the effect is systemic or local. The effect may stem from decreased nociceptive C-fibre activity via a direct action on glucocorticoid receptors and inhibitory potassium channels. Another suggestion is a vasoconstrictive effect, which reduces the systemic uptake of local anaesthetics or a systemic anti-inflammatory effect.