**2.2 Adrenaline**

The inclusion of adrenaline in LIA cocktail is safe, but it is not well understood whether including it improves outcomes. Adrenaline works as vasoconstrictive agent which prolongs the local anaesthetic effect [21]. However, there is a concern in the recent literature for the usage of adrenaline and its impacts on vasoconstriction and skin necrosis [21, 22].

Van Der Zwaard et al. studied 502 TKA and unicondylar knee replacements, and compared one group of LIA with ropivacaine only with the other group of ropivacaine and epinephrine [23]. They found there was no difference in pain scores between the two groups. The authors of this chapter found the usage of adrenaline in a staged injection technique has benefits. Adrenaline prolongs the effect of local anaesthetic and decrease bleeding which mitigates swelling and haematoma formation, subsequently facilities early mobilisation. We recommend proximal infiltration deep to the deep fascia rather than injecting the skin and subcutaneous in TKR to avoid skin necrosis.
