Table 3.

Multiple linear regression analysis to determine factors for improving knee-joint range of motion.

	Model 1		Model 2		Model 3		Model 4
	Coefficient β	P	Coefficient β	P	Coefficient β	P	Coefficient β	P
Reduction of tIA-tophi	0.769	0.013	0.783	0.013	0.781	0.017	0.839	0.019
Age at initial visit			−0.126	0.557	−0.124	0.588	−0.109	0.644
Subcutaneous tophi duration					−0.013	0.971	0.027	0.942
Extra-articular knee tophi							−2.334	0.622

Dependent variable: improvement of knee-joint range of motion; Independent variables: Model 1, reduction of total intra-articular tophi size (tIA-tophi); Model 2, reduction of tIA-tophi and age at initial visit; Model 3, reduction of IA-tophi, age at initial visit, and subcutaneous tophi duration; Model 4, reduction of IA-tophi, age at initial visit, subcutaneous tophi duration, and presence of extra-articular knee tophi.