Co-administration of hyaluronic acid with local anaesthetics shows lower cytotoxicity than local anaesthetic treatment alone in bovine articular chondrocytes

OBJECTIVE: To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro. METHODS: Chondrocytes were harvested from bovine femoral condyle cartilage and isolated using collagenase-containing media. At 24 hours after seeding 15 000 cells per well onto a 96-well plate, chondrocytes were treated with media (DMEM/F12 + ITS), PBS, 1:1 lidocaine (2%):PBS, 1:1 bupivacaine (0.5%):PBS, 1:1 lidocaine (2%):HA, 1:1 bupivacaine (0. 5%):HA, or 1:1 HA:PBS for one hour. Following treatment, groups had conditions removed and 24-hour incubation. Cell viability was assessed using PrestoBlue and confirmed visually using fluorescence microscopy. RESULTS: Media-treated groups had a mean of 1.55×10(4) cells/well (sem 783). All treated cells showed statistically significant reduced viability when compared with media alone (all p < 0.003). Cells treated with bupivacaine + HA (6.70×10(3) cells/well (sem 1.10×10(3))) survived significantly more than bupivacaine (2.44×10(3) cells/well (sem 830)) (p < 0.001). Lidocaine + HA (1.45×10(3) cells/well (sem 596)) was not significantly more cytotoxic than lidocaine (2.24×10(3) cells/well (sem 341)) (p = 0.999). There was no statistical difference between the chondrotoxicities of PBS (8.49×10(3) cells/well (sem 730) cells/well) and HA (4.75×10(3) cells/well (sem 886)) (p = 0.294). CONCLUSIONS: HA co-administration reduced anaesthetic cytotoxicity with bupivacaine but not lidocaine, suggesting different mechanisms of injury between the two. Co-administered intra-articular injections of HA with bupivacaine, but not lidocaine, may protect articular chondrocytes from local anaesthetic-associated death. Cite this article: Bone Joint Res 2013;2:270–5.