Table 1.

Characteristics of subjects without knee pain (A), with right knee pain (B), and with bilateral knee pain (C). Age, BMI, and WOMAC pain scores are displayed as mean ± SD. Frequencies of gender and OA risk factors are given in absolute numbers and on percentage basis.

	A: Subjects without knee pain (n=60)	B: Subjects with right knee pain (n=30)	C: Subjects with bilateral knee pain (n=30)
male	30 (50%)	15 (50%)	15 (50%)
age [years]	50.8±3.0	50.3±2.9	51.5±2.9
BMI [kg/m²]	27.6±3.6	28.8±4.8	28.3±4.8
WOMAC pain score right knee	0.0±0.0*	6.8±2.2*	8.6±2.5*
WOMAC pain score left knee	0.0±0.0*	0.0±0.0*	6.8±3.1*
any pain, aching, or stiffness in or around either knee in the past 12 months	53 (88.3%)*	30 (100%)*	30 (100%)*
history of knee injury in either knee	32 (53.3%)	16 (53.3%)	13 (43.4%)
history of knee surgery in either knee	9 (15.0%)	6 (20.0%)	8 (26.7%)
family history of total knee replacement	10 (17.2%)*	8 (27.6%)*	0 (0%)*
Heberden‘s nodes	13 (21.7%)	4 (13.3%)	5 (16.7%)
frequent knee bending activities	45 (47.4%)	24 (25.3%)	26 (27.4%)

^*indicates statistically significant differences between the subject groups (p<0.05).