Use of a Hyperosmolar Saline Solution to Mitigate Proinflammatory and Degradative Responses of Articular Cartilage and Meniscus for Application to Arthroscopic Surgery

This study was designed to evaluate differences in proinflammatory and degradative mediator production and extracellular matrix degradation from osteoarthritic knee articular cartilage and meniscus explants treated with either hyperosmolar saline or isotonic saline. 6 mm-diameter full-thickness explants were created from articular cartilage and menisci recovered after patients underwent knee surgery. One explant half was treated for 3 hours with hyperosmolar saline (600 mOsm/L) and the corresponding half with isotonic saline (300 mOsm/L). Explants were subsequently cultured for 3 days in tissue culture media. On day 3, media were collected for biomarker analyses. Results were normalized to tissue wet weight and analyzed statistically. Articular cartilage was collected from 10 patients (5 male, 5 female; mean age = 66.9 years) and menisci were collected from 8 patients (2 male, 6 female; mean age = 66 years). Articular cartilage media concentrations of monocyte chemoattractant protein-1 (P = .001) and interleukin (IL)-6 (P = .049) were significantly lower in explants treated with hyperosmolar saline. Meniscus media concentrations of prostaglandin E2 (P = .008), monocyte chemoattractant protein-1 (P = .011), IL-6 (P = .029), IL-8 (P = .012), matrix metalloproteinase-2 (P = .011), and glycosaminoglycan (P = .008) were significantly lower in explants treated with hyperosmolar saline. Treatment of cartilage and meniscus explants with hyperosmolar saline effectively mitigated key proinflammatory mediator production, as well as degradative mediator production and glycosaminoglycan loss from meniscus, with no detrimental effects noted compared to isotonic saline. These results suggest that hyperosmolar saline irrigation fluid may provide a safe alternative to standard isotonic saline irrigation fluid, and could mitigate untoward effects associated with inflammatory responses after standard-of-care knee arthroscopy.