A number of anaesthetics are used routinely in clinical practice. Those most commonly used are all amino amides, which are very stable in solution and metabolised by the liver.
Amino amides
Lidocaine
Lidocaine is a short-acting local anaesthetic. It has a half-life of 1.5 hours and a duration of action of 3 hours. In recent in vitro studies, it was shown that the 1% and 2% strengths produce the greatest toxicity to chondrocytes and therefore should not be used for intraarticular injection. Lidocaine can be safely used to provide intradermal and subcutaneous analgesia.
Bupivacaine
Bupivacaine is a longer-acting anaesthetic with a half-life of 3 hours and a duration of action of 6 hours. It is routinely used in intraarticular injections; however, recent in vitro studies show that chondrocyte death is increased with the 0.5% strength but not the 0.25% strength. We would therefore advocate using bupivacaine hydrochloride 0.25% routinely in practice. Even if a structure does not have a direct intraarticular extension, this strength provides enough analgesia while avoiding the risk of inadvertent joint exposure.
Mepivacaine
Mepivacaine is not used routinely in the United Kingdom.
Amine amide with S enantiomer
These are said to be less toxic, more potent and therefore longer lasting.
Ropivacaine
Much longer acting with a half-life of 6 hours and a duration of action of 12 hours. The lower strength of 0.5% is not chondrotoxic according to the literature but 0.75% is chondrotoxic.
Levobupivacaine
Levobupivacaine is not used routinely in the United Kingdom.
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