Arthroscopic irrigation of the bovine stifle joint increases cartilage surface friction and decreases superficial zone lubricin

The purpose of this study was to determine the effects of arthroscopic irrigation on cartilage superficial zone lubricin and surface friction. Arthroscopic partial meniscectomy is one of the most commonly performed orthopedic surgeries in the United States, but rates of osteoarthritis progression following this procedure are high. The effect of arthroscopic irrigation on articular surface lubrication has not been previously considered as a contributing factor in outcomes after arthroscopy. Fourteen bovine stifle joints were randomized to receive arthroscopic irrigation (n=7) or no treatment (n=7). Full-thickness osteochondral explants from these joints underwent friction testing to measure static and dynamic coefficients of friction. Following mechanical testing, samples were fixed and stained for lubricin. Percent integrated density, a measure of the amount of lubricin in the superficial zone (0-100µm depth), was determined. Static and dynamic coefficients of friction were found to be significantly greater in arthroscopy specimens compared to controls (p=0.02 and p<0.001, respectively). Percent integrated density of lubricin in the superficial zone was significantly lower in arthroscopy specimens compared to controls (p<0.001).