Effect of levobupivacaine on articular chondrocytes An in- vitro investigation

BACKGROUND Intra- articular injection of local anaesthetics is a technique commonly used to enhance postoperative analgesia following arthroscopic surgery. However, the potential for cartilage damage due to toxicity of intra-articular local anaesthetics is a concern. Most studies indicate that the toxic effect is drug and time dependent. OBJECTIVES The objective of this study is to compare the in-vitro chondrotoxic effect of levobupivacaine on human cartilage with saline and bupivacaine. DESIGN An experimental study. SETTING University hospital. PARTICIPANTS Adult patients undergoing knee surgery. INTERVENTIONS Human articular cartilage was harvested and removed from five patients during knee replacement surgery. Chondrocytes were cultured and divided into three groups exposed to bupivacaine 0.5%, levobupivacaine 0.5% or physiological saline for 15, 30 or 60 min. MAIN OUTCOME MEASURES Viability of human cartilage cells after contact with the different study drugs at different durations of exposure using two techniques: live/ dead cell viability flow cytometry analysis and trypan blue exclusion assay. RESULTS At 1 h of exposure, chondrocyte mortality in cartilage explants was significantly greater after treatment with levobupivacaine or bupivacaine than with saline (25.9% +/- 14.1, 20.7% +/- 10.4 and 9.6% +/- 5.4, respectively). No differences between groups were found when exposure to the experimental drug was limited to 15 or 30 min. CONCLUSION In-vitro 0.5% levobupivacaine is more chondrotoxic than saline in human articular cartilage after 1 h of exposure. Bupivacaine seems to be less chondrotoxic than levobupivacaine. With shorter exposures, no clear chondrotoxic effect was shown