Table 6.

Baseline frequencies of semi-quantitative MRI biomarkers –hoffa- and effusion-synovitis

MRI feature	Biomarker	Overall n (%)	Controls	Cases	p-value
Hoffa-synovitis					0.004*
	0	246 (41 %)	186 (45.8 %)	60 (30.9 %)
	1	302 (50 %)	190 (46.8 %)	112 (57.7 %)
	2	47 (8 %)	26 (6.4 %)	21 (10.8 %)
	3	5 (1 %)	4 (1.0 %)	1 (0.5 %)
Effusion-synovitis					0.560
	0	233 (39 %)	156 (38.4 %)	77 (39.7 %)
	1	250 (42 %)	176 (43.3 %)	74 (38.1 %)
	2	97 (16 %)	62 (15.3 %)	35 (18.0 %)
	3	20 (3 %)	12 (3.0 %)	8 (4.1 %)

*statistically significant at p < 0.05; p values refer to differences between cases and controls across all grades