Table 3.

Unadjusted association of income with pain, activity limitation and improvement in knee function after primary total knee arthroplasty

	2 years				5 years
	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value
Pain/function:	Moderate to severe pain		Moderate to severe functional limitation		Moderate to severe pain		Moderate to severe functional limitation
≤ US$35, 000	0.68 (0.50 to 0.92)	0.01	0.82 (0.67 to 0.99)	0.04	0.86 (0.60 to 1.22)	0.39	0.92 (0.74 to 1.15)	0.47
> US$35, 000 to US$45, 000	0.80 (0.64 to 1.01)	0.06	0.99 (0.85 to 1.15)	0.90	0.90 (0.65 to 1.25)	0.55	1.00 (0.82 to 1.23)	0.99
> US$45, 000 (ref)	1.00		1.00		1.00		1.00
Improvement:	Better		Much better		Better		Much better
≤ US$35, 000	1.5 (0.9 to 2.4)	0.13	1.1 (0.7, 1.7)	0.61	1.2 (0.7 to 2.0)	0.57	1.2 (0.8 to 1.9)	0.39
> US$35, 000 to US$45, 000	1.1 (0.7 to 1.6)	0.72	1.0 (0.7 to 1.5)	0.83	1.1 (0.7 to 1.7)	0.78	1.1 (0.8, 1.7)	0.56
> US$45, 000 (ref)	1.00		1.00		1.00		1.00