Effects of Adding Epinephrine to Arthroscopic Irrigation Fluid on Cultured Chondrocyte Survival In Vitro

PurposeThis study evaluates the effect of low doses of epinephrine contained in common arthroscopic irrigation solutions on viability of in vitro human articular chondrocytes during short-term exposure.MethodsIsolated cultured human chondrocytes were treated with culture medium, normal saline solution, 1:300,000 epinephrine solution (equivalent to 10 mL of 1:1,000 epinephrine added to a 3-L saline solution bag), or 1:3,000,000 epinephrine solution (equivalent to 1 mL of 1:1,000 epinephrine added to a 3-L saline solution bag) for 1 hour (N = 84). Twenty-four hours after treatment, chondrocyte viability was measured. Statistical analysis was performed with an analysis of variance with Bonferroni post-test.ResultsChondrocyte viability was significantly better when exposed to normal saline solution alone versus high-dose 1:300,000 epinephrine (87.9% ± 5.4% v 74.6% ± 9.4%, P < .05). Exposure to low-dose 1:3,000,000 epinephrine had significantly better survival versus high-dose 1:300,000 epinephrine (85.0% ± 8.3% v 74.6% ± 9.4%, P < .05). There was no difference in viability after exposure to low-dose 1:3,000,000 epinephrine versus normal saline solution (85.0% ± 8.3% v 87.9% ± 5.4%, P > .05).ConclusionsIn vitro, normal saline solution and low-dose 1:3,000,000 epinephrine are significantly less toxic than high-dose 1:300,000 epinephrine to cultured human articular chondrocytes.Clinical RelevanceThis in vitro study suggests that arthroscopic irrigation fluid containing 1:3,000,000 epinephrine is less chondrotoxic than solutions containing 1:300,000 epinephrine. Surgeons may wish to use the least amount of epinephrine required for adequate visual clarity during surgery. This study does not establish a contraindication to the use of higher doses of epinephrine.