Inflammatory cytokine response following acute tibial plateau fracture

Background: The objective of the present study was to evaluate human synovial fluid for inflammatory cytokine concentrations following acute tibial plateau fracture. Our hypothesis was that there would be an elevated inflammatory response following intra-articular fracture, and that the inflammatory response would be greater after high-energy compared with low-energy injuries. Methods: Between December 2011 and June 2013, we prospectively enrolled forty-five patients with an acute tibial plateau fracture. Synovial fluid aspirations were performed on the injured and uninjured knees. Twenty patients who required an external fixator followed by delayed fixation underwent aspiration at both surgical procedures. The concentrations of interferon-gamma (IFN-γ), interleukin-1 beta (IL-1β), interleukin-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-12(p70), IL-13, IL-17A, tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β) were quantified with use of multiplex assays. Results: The forty-five patients had an average age of forty-two years (range, twenty to sixty years). There were twenty-four low-energy and twenty-one high-energy tibial plateau injuries. There was a significant difference between injured and uninjured knees (p < 0.001) with regard to concentrations of IL-1β, IL-6, IL-8, IL-10, IL-1RA, and MCP-1. There was not a detectable difference in synovial fluid cytokine concentrations between high and low-energy injuries. The concentrations of IL-10 (p < 0.001), IL-1RA (p = 0.002), IL-6 (p < 0.001), IL-8 (p < 0.001), and MCP-1 (p = 0.002) were significantly greater in the injured knee than in the uninjured knee at the second aspiration, at a mean of 9.5 days (range, three to twenty-one days) after the initial injury. Conclusions: There was a significant local inflammatory response following acute tibial plateau fracture. There was not a detectable difference in inflammatory cytokine concentration between high and low-energy injuries. Synovial fluid concentrations of IL-10, IL-8, IL-6, IL-1RA, and MCP-1 remained elevated at the second aspiration. Clinical Relevance: The articular surface is exposed to acute and sustained concentrations of multiple inflammatory cytokines following intra-articular fracture. Inflammatory cytokines have been associated with the development of primary and inflammatory arthritis, and this research indicates that these factors could also play a role in the development of posttraumatic osteoarthritis.