Table 1.

Correlation coefficients and Cronbach's alpha for the scales used in this study.

#	Factor	1	2	3	4	5	Cronbach's alpha
1	Total WOMAC scale	—					0.84
2	Pain severity	0.62∗∗	—				0.76
3	Joint stiffness	0.31∗∗	0.37∗∗	—			0.62
4	Physical functioning impairment	0.71∗∗	0.30∗∗	0.46∗∗	—		0.79
5	Psychological demand (SF-36)	0.28∗∗	0.21∗∗	0.01	0.22∗∗	—	0.76

^∗∗ P value: <0.001.