Proportion ARGS of aggrecan in the study groups. The molar proportion of aggrecan fragments in synovial fluid (SF; measured by Alcian blue precipitation) detected as ARGS neoepitope fragments (measured by ARGS ELISA) in the study groups healthy knee reference (REF), acute inflammatory arthritis (AA), acute knee injury (AI), chronic knee injury (CI), and knee osteoarthritis (OA). The boxes define the 25th and 75th percentiles with a line at the median, error bars defining the 10th and 90th percentiles and circles represents individual outliers. After Bonferroni correction, P values below 0.013 are considered significant to retain the 0.05 overall significance level. Conversion from microgram sulfated glycosaminoglycan (sGAG)/ml to pmol aggrecan/ml was made assuming an average aggrecan molecular weight of 1.5 × 106 g/mol and that 75% of this weight was sGAG.