Bupivacaine chondrotoxicity.

Editor—We commend Webb and Ghosh for their editorial reviewing the growing evidence for the chondrotoxicity of intra-articular bupivacaine. We would like to add three further points for your readers’ consideration. First, neither magnesium nor bupivacaine is licensed for intra-articular use, although bupivacaine has a good safety record given by this route. Nevertheless, now patient harm has been raised as a potential concern, it should be incumbent on anaesthetists to consider alternative methods of providing analgesia after arthroscopy, until such time as research is performed to confirm or refute chondrotoxicity. Secondly, as stated in the editorial, ropivacaine 0.5% appears to be less chondrotoxic than bupivacaine 0.5%. Although not yet reported, the relative analgesic potencies of ropivacaine and bupivacaine suggest that 0.375% (or even 0.2%) intra-articular ropivacaine may provide equivalent postoperative analgesia, but with reduced chondrotoxicity. Finally, and although unlicensed, magnesium (1 g in 20 ml saline) might provide a viable alternative or dosesparing adjuvant to intra-articular bupivacaine. 4 Crucially, recent in vitro research suggests that supraphysiological doses of magnesium appear to be chondroproliferative. We would advocate the use of magnesium sulphate 1 g as the primary intra-articular analgesic for knee arthroscopy, augmented (if at all) by ropivacaine 0.2%.