Table 5.

Performance characteristics of physical examination tests for detecting effusion-synovitis on MRI in

	Bulge sign*Present (total) = 107 (17.8%)		Patellar tap sign* Present (total) = 28 (4.7%)
	Effusion-synovitis ≥ 1 (n=367)	Effusion-synovitis ≥ 2** (n=117)	Effusion-synovitis ≥ 1 (n=367)	Effusion-synovitis ≥ 2 (n=117)
Test positive, n (%)	81 (22.1)	44 (37.6)	16 (4.4)	9 (7.7)
Test negative, n (%)	286 (77.9)	73 (62.4)	351 (95.6)	108 (92.3)
Sensitivity (%)	22.0	37.6	4.3	7.6
Specificity (%)	88.8	86.9	94.8	96.0
Positive predictive value (%)	75.7	41.1	57.1	32.1
Negative predictive value (%)	41.9	85.1	38.6	81.2
Accuracy (%)	48.0	77.3	39.5	78.8

^*Assessed on the index knee.

^**Compared with individuals with scores 0 and 1.