Effect of Arthroscopic Lavage on Systemic and Synovial Fluid Serum Amyloid A in Healthy Horses.

Abstract

To evaluate the effect of arthroscopic lavage on systemic serum amyloid A (SAA) and SAA, total protein, nucleated cell count, and percentage of neutrophils in synovial fluid in healthy horses. Prospective experimental study. Healthy adult horses (n = 6). Middle carpal joints were randomly assigned to 1 of 2 treatments: arthrocentesis (controls) or arthroscopic lavage, with 30 day washout period between treatments. Synovial fluid and blood samples were collected at 0, 24, 48, 72, 96, and 120 hours. Measurements included systemic and synovial fluid SAA, as well as total protein, nucleated cell count, and percentages of neutrophils in synovial fluid. Data were analyzed by median quantile regression and Wilcoxon signed-rank test and significance level set at P < .05. Systemic and synovial fluid SAA did not increase from baseline (except systemic SAA at 24 hours for both treatments) and were not significantly different between treatments. Total protein values were significantly increased after arthroscopic lavage (except at 96 hours) but not in controls at all time points. With both treatments, nucleated cell counts significantly increased from baseline values at all time points. Percentages of neutrophils were significantly increased after arthroscopic lavage at all time points, but only at 24 hours in controls. Total protein, nucleated cell count, and percentage of neutrophils in synovial fluid were significantly increased after arthroscopic lavage; however, synovial fluid SAA was not affected by this procedure. Further research is warranted to validate synovial fluid SAA as a monitoring tool during treatment of septic arthritis.