Higher aggrecan 1-F21 epitope concentration in synovial fluid early after anterior cruciate ligament injury is associated with worse knee cartilage quality assessed by gadolinium enhanced magnetic resonance imaging 20 years later

Table 2 Concentration of biomarkers, expressed as median values (25th and 75th percentiles), in acute and chronic samples

Biomarkers	Acute samples		Chronic samples		¹P-values
	Concentration	N	Concentration	N
sGAG, μg/ml	181.8 (116.8, 323,8)	16	58.1 (42.8, 75,1)	21	< 0.001
1-F21 agcan, μg/ml	679.0 (413.4, 873.6)	16	117.0 (85.6, 168.3)	14	< 0.001
ARGS agcan, nM	11.5 (6.8, 21.1)	18	1.5 (1.1, 2.1)	22	< 0.001
COMP, μg/ml	180.0 (146.5, 214.5)	13	57.0 (52.3, 73.0)	12	< 0.001
MMP-3, nM	37.5 (21.4, 56.8)	18	5.2 (1.5, 8.5)	17	< 0.001
TIMP-1, nM	52.5 (43.1, 67.8)	18	7.3 (5.7, 9.3)	17	< 0.001
sGAG/COMP	1.08 (0.7, 1.6)	11	0.9 (0.8, 1.1)	12	0.295
1-F21 agcan/COMP	4.9 (1.7, 5.7)	11	1.5 (1.2, 2.5)	9	0.038
ARGS agcan/COMP	0.07 (0.04, 0.10)	12	0.02 (0.02, 0.03)	12	0.002
MMP-3/TIMP-1	0.7 (0.4, 1.1)	18	0.6 (0.3, 1.0)	17	0.642

¹⁾ Statistical analyses using Mann Whitney.
sGAG Sulfated glycosaminoglycans, 1-F21 agcan 1-F21 epitope of aggrecan, ARGS agcan ARGS neoepitope of aggrecan, COMP Cartilage oligomeric matrix protein, MMP-3 Matrix metalloproteinase 3, TIMP-1 Tissue inhibitor of metalloproteinase 1.

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